Re:case of units
If you want to stop mu being translated back to m don't insert it from the symbols font. Most normal windows fonts have it as a character. Put the num lock on the keyboard on, hold down the alt key and type on the number pad 0181 other useful codes are degrees 0176 plus or minus 0177 half 0189 quarter 0188 squared 0178 cubed 0179 Millifarad sized capacitors are now common and I have seen one instance of one marked mF. With the new double layer supercaps multifarad rated capacitors are also available and someone is marketing a 28kF capacitor or if you prefer 0.028MF Nick Rouse - Original Message - From: Wan Juang Foo f...@np.edu.sg Dear all, The capital W is probably a font translation error that was not spotted. I had much heart ache over this whenever I print something in a different computer. I have had much experience with entire documents that have the greek lower case m (micro=u=greek mu) being substituted for a plain lower case m etc... It is very frustrating. This bring to mind a similar and more widely use practice in marking electrolytic capacitors e.g. 10mfd instead of 10uF. It is oblivious to the experienced engineer, mfd is read as micro Farad knowing that the milli Farad component is probably the size of a chair! I wonder if this will catch any technical types by surprise. :-) Tim Foo --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: IEC 60601-2-24 / Magnetic Field
I'm no medical Guru either but I know the sort of field levels involved. They range from about .5 to 3 teslas. This is not much higher than the fields in the gaps of electrical motors and generators (up to 1.8T in normal silicon iron and up to 2.1 T in cobalt iron used in aerospace machines) The difference is the length of the effective magnetic dipole. The field in an MRI machine is almost constant across the whole bore of the machine and for whole body machines this gives a dipole length of a metre or more. You are still in the near field up to a couple of dipole lengths before the field strength starts drooping as the inverse cube of the distance. Thus it is quite possible to have fields up 1T a metre or more from the machine this corresponds to an H field of 790 kA/m and this is sufficient to lift large ferromagnetic objects. The dipole length in a normal electrical machine is about the size of the air gap, about 1mm or less. Thus there are very strong magnetic fields only out to a few centimetres. I don't know if this is the reasoning behind the field values in IEC 60601-2-24 but if it is the levels do not seem unreasonable. Nick Rouse . - Original Message - From: Chris Maxwell chris.maxw...@nettest.com To: am...@westin-emission.no; emc-p...@majordomo.ieee.org Sent: Tuesday, April 30, 2002 4:22 PM Subject: RE: IEC 60601-2-24 / Magnetic Field Hi Amund, I read your email (below). I'm no medical device expert; but I'm wondering if the magnetic strength limit was set so high due to MRI (Magnetic Resnonance Imaging) devices. My understanding is that MRI devices produce HUGE magnetic field levels. According to a recent newspaper story that I read, these fields are strong enough to draw a metal oxygen tank across the room to the MRI machine. Is there any chance that the device in question could be used around an MRI? It would be a real bummer if someone's infusion pump suddenly changed its run rate due to a nearby magnetic field. Could that be what the standard is safeguarding against? Any medical device gurus care to comment? Chris Maxwell | Design Engineer - Optical Division email chris.maxw...@nettest.com | dir +1 315 266 5128 | fax +1 315 797 --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: U.S. Safety Regulations
George I fail to follow your argument, The fact that you have not been challenged or taken to law by any member state does not mean that it is not the laws of the member states that have legal juristriction. You have not been taken to the European courts of justice either. you say:- For ITE, the EU requires compliance to the Low Voltage and EMC Directives No, the EU requires that member states put in place national laws requiring compliance in that country of the requirements of the Low Voltage and EMC Directives. This is somewhat different. Had you transgressed and been prosecuted you would have been prosecuted under the national law of the country. If for instance you had been taken to court in the UK in relation to EMC problems you would not be accused of contravening directive 89/336/EEC, you would be accused of contravening the UK Electromagnetic Compatibility Regulations 1992 (SI 19992/2372) In Germany the same action will have you in conflict with Gesetz über die elektromagnetische Verträglichkeit von Geräten, (EMVG) In Belgium you will run foul of Royal decree of May 18th 1994 concerning electromagnetic compatibility; and in Greece Ministerial Decision number 94649/8682/ 93/25-8-94 And in each case it is you the manufacturer dealer or user that will be taken to court. It is not the country that will be prosecuted and it is not a matter of allowing entry. Crossing borders as such is not an offence either for an individual or a member state. The offence is placing on the market or taking into service non-compliant equipment at any point in the EU. The fact that you have not had any trouble with any of these national laws is good news, long may it remain so. However this does not change the fact that these are the laws under which manufacturers, dealers and users operate in the various countries and you should beware of the subtle differences between them. Nick Rouse - Original Message - From: geor...@lexmark.com To: Nick Rouse nickjro...@cs.com Cc: emc emc-p...@majordomo.ieee.org Sent: Monday, March 25, 2002 5:16 PM Subject: Re: U.S. Safety Regulations Nick, To some degree, I beg to differ with your explanation, particularly with the following: It is these national regulations that have direct force of law on manufacturers, traders and users of equipment in that member state. It is not a matter of crossing boundaries into the EU or between member states, and not a matter of it being just wise to meet the various requirements. Wherever you are in the EU you will be breaking a local national law if you do not. For ITE, the EU requires compliance to the Low Voltage and EMC Directives. They have further listed harmonized standards which are deemed sufficent to comply. Under the present process, a manufacturer can obtain a CB Report of create a Technical Construction File to meet the LVD, and take EMC data at an authorized test site to meet the EMC Directive. At that point the manufacturer can apply the CE marking, and file a EU Declaration of Conformity within the EU. Since this process was adopted by the EU, we have not had a single EU member state ask to see either our DoC or our background test data/reports. So, there are no national regulations, but only the EU regulations, which were designed to do away with the many diveregent national regulations. Again, the EU law applies to member states, over which the EU has some power. There is no law pertaining to mfrs, but the Directives as to what the member states are to do to ensure safe products. If a mfr manages to place a product on the market that does not meet the LV or EMC Directives, it is the member state which allowed entry of the product that is held accountable. Of course, a mfr found doing this would have to remove the product from the market and would have a hard time doing future business in the EU. George Alspaugh Nick Rouse nickjrouse%cs@interlock.lexmark.com on 03/22/2002 04:44:05 PM To: emc emc-pstc%majordomo.ieee@interlock.lexmark.com, George_Alspaugh/Lex/Lexmark.LEXMARK@sweeper.lex.lexmark.com cc:(bcc: George Alspaugh/Lex/Lexmark) Subject: Re: U.S. Safety Regulations Thanks George for your outline of the basic way US safety works. Perhaps I may expand a bit on how EU directives works. First the EU directives are, as you say, not in themselves directly law in any of the member states. What they do is to direct each of the member states to pass into their national laws regulations emboding the requirements of the directive and most importantly to repeal any other legislation that lays any requirement in the aera covered on anyone placing relavant products on the market or taking them into service. The member states are bound to do this under the terms of the treaty of Rome and other European treaties. Any member state not properly transposing a directive into national Law is in principle liable to be taken
Re: U.S. Safety Regulations
Thanks George for your outline of the basic way US safety works. Perhaps I may expand a bit on how EU directives works. First the EU directives are, as you say, not in themselves directly law in any of the member states. What they do is to direct each of the member states to pass into their national laws regulations emboding the requirements of the directive and most importantly to repeal any other legislation that lays any requirement in the aera covered on anyone placing relavant products on the market or taking them into service. The member states are bound to do this under the terms of the treaty of Rome and other European treaties. Any member state not properly transposing a directive into national Law is in principle liable to be taken by the Commission to the European Courts. The wording of the directives, heavy on permissive clauses and requirements on governments to allow goods to be moved, sold and put into service, surprises some people but it must be remembered that the wellspring of most of this legislation is the idea of a single European Market. The member states are not allowed to have local regulations that may act as an indirect trade barrier favoring local suppliers over those of other member states. By a having just a unified set of European technical requirements it is hoped to create a level playing field for all paticipants in the European market. The directives are usually implimented by some form of secondary legislation. Here in the UK we use things call statutary instruments. The Single European Market Act of 1987 was passed through the full legislative process but gives thereafter ministers of the crown the right to draft statutary instruments to impliment directives into UK law. They are placed in the libaries of both houses of parliment and it is in principle open to the members of parliament to pass a resolution anulling these instruments. In practice this never happens and after 7 days they automatically become statute law. It is these national regulations that have direct force of law on manufacturers, traders and users of equipment in that memmber state. It is not a matter of crossing boundaries into the EU or between member states, and not a matter of it being just wise to meet the various requirements. Wherever you are in the EU you will be breaking a local national law if you do not . The various national implimentations should all be the same but just to remind everyone that we still are 15 independant countries, there are small quirks in the the various implimentations that the Commission has not thought serious enough to stamp on. One such if the UK modified application of the EMC directive to educational establishments. In addition the member states may apply to the Commission for the right to have extra local laws to meet special local requirements An example of this is the UK 1994 Plugs and Sockets etc.(Safety) regulations that require the fitting of UK style fused plugs to equipment solt to comsumers. Nick Rouse - Original Message - From: geor...@lexmark.com To: emc-p...@ieee.org Sent: Thursday, March 21, 2002 9:57 PM Subject: U.S. Safety Regulations There seems to be some confusion regarding U.S. product safety regulations. It is not as complicated as some have made it appear. I will try to simplify this topic. First, the European Directives may be EU law, but they are only directed to member states, not manufacturers, over which they have no legal authority. Read the text of some Directives. The EU Directives outline to member states what standards products must meet to enter the EU via any country border. Hence, manu- facturers who wish to market in the EU would be wise to adhere to the LVD and other applicable Directives. The U.S. OSHA regulations are virtually the same in this respect. These regs describe what employers must do to ensure a safe workplace. The employer is barred under OSHA rules from allowing employees to use specified products that do not meet OSHA require- ments. Hence, manufacturers who wish to market in the U.S. to businesses would be wise to adhere to OSHA requirements. Now, it is somewhat true that electrical products for the U.S. can either be NRTL approved for total U.S. distribution, or be approved by every local city/county electrical safety authority. BTW, this is an option that does not exist within the EU that I know of. Now, which method do you think is easier and less costly? Duh! I assure you it is the NRTL route, even if you desire to enter only one local market. There have been several opinions offered as to why any U.S. (or other) safety regs exist. My personal opinion is that manufacturers should apply the following concepts, in the order given: - provide products that will not cause injury or property damage - provide products that meet the standards - provide products that exceed the standards if appropriate
Re: Teslars???
To be pedantic, you are mixing units of two different quantities there Mike. Tesla and gauss are units of magnetic flux density, the B field Ampere/metre and oersted are units of magnetic field strength, the H field. Only in a vacuum does 1A/m generate a flux density of exactly 0.4 pi µT In air its pretty close but in ferromagnetic materials it can be thousands of times bigger. The field strengths mentioned in the original question are not all that outrageous. Most transformers, motors and generators with electrical steel laminations operate at peak flux densities of 1.4T to 1.7T within the core. At a boundary between two materials of different permeabilities the tangential component of H and the normal component of B are the same either side of the boundary. The amplitude relative permeability of electrical steels near their maximum working flux density is only about 300 to 800. So with the flux flowing along the core at a flux density of say 1.5T and an amplitude relative permeability of 500, you get a flux density close to the core surface of 3mT. While you are in the near field (distances small with respect to the size of the magnetic circuit) this will not drop very fast. in the far field it drops according to the inverse cube dipole law. Things are even worse at the corners. The flux does not turn smart right angles just because the core does and so the flux is not parallel to the core. This increases the flux density close outside the core. Worse yet are the effects of gaps. Laminations in transformers are commonly made in two parts that fit together to form the complete lamination. C T shape or E and I shape. This is done so that the winding can be put on the bobbin first and then the core built up. Where the two parts of the lamination meet up there is always a small gap the size of which depends on the quality of the laminations and the care with which the core is assembled. Good practice is to alternate the orientation of the laminations so that the gaps do not align but in some cheap devices the laminations are stacked up with the gaps aligned.These devices also tend to be those using poorly cut laminations. Gaps of half a millimetre are not unknown.they also tend to push the flux density up closer to the limit increasing the external flux even more because of the lower amplitude relative permeability Gaps in rotating machines can be even bigger . Since the flux crosses the gap almost normally the flux in the gap is the same as in the core 1.4T -1.7T At the edge of the core this flux bulges out into a fringing field. Fortunately this enters the far field dipole law at distances large compared to the gap length and width. Even so fields of tens of mT can be found within a few centimetres of the gap. So take a large poorly built transformer or solenoid and push the core hard up against the equipment housing and you could well exceed 0.7 mT nearby. Several metres from a train is a bit less likely but not impossible These figures should be borne in mind the next time you read about the dangers of the magnetic field from overhead power lines. I have several times seen building site welders sitting on their transformers with their testicles dangling over the gap and I haven't seen welders dropping like flies. Nick Rouse - Original Message - , From: Mike Cantwell mike.cantw...@flextronics.com To: emc-pstc (E-mail) emc-p...@majordomo.ieee.org Sent: Friday, February 08, 2002 2:53 PM Subject: RE: Teslars??? I think the units you're looking to compare to would be Amps/meter. The conversion from Tesla to A/m is: 1 A/m = 1.26 uT = 0.0126 Gauss Therefore, a field of .7 mT converts to 555 A/m !!! (it is also equivalent to 10 Gauss) Assuming that your customer is referring to power frequency magnetic fields, this would be substantial, to say the least. I would recommend that you question your customer a little further as to how they determined this field strength requirement. It seems high by a factor of about 1000. Good luck, Mike -Original Message- From: marti...@appliedbiosystems.com [mailto:marti...@appliedbiosystems.com] Sent: Thursday, February 07, 2002 4:22 PM To: emc-p...@majordomo.ieee.org Subject: Teslars??? We have a customer that is concerned about how our product, laboratory equipment, will respond to electromagnetic disturbances from a high speed train that runs close to their lab. The customer states that the disturbance will be around 0.7-1.2 m Teslar. Can someone please explain what the unit Teslar is and how that unit relates, or if it relates, to the immunity tests of EN 61000-4-3 Radiated immunity, or any other immunity test. Has anyone ever had a similar concern from a customer dealing with this type of disturbance? Your responses are appreciated. Regards Joe Martin EMC/Product Safety Engineer Applied Biosystems marti...@appliedbiosystems.com
Re: broadband RE from AC induction motors
Corona discharge can occur when air is electrically stressed near its break down limit and this will generate broadband RF energy. If you have small bubbles of air in a insulator with a fairly high dielectric constant in an electrical field it produces an effect known as dielectric focusing and produces a electric field strength in the air in the bubble many times that given by the voltage across the insulator divided by the thickness of the insulator. If this field strength is strong enough to cause any ionised air molecules that are around (and there always a few from the effects of cosmic rays if nothing else) to be accelerated to sufficient velocity before they bump into other molecules for them to ionise them then this can lead to a cascade. Eventually at high enough fields this can lead to full blown arcing but before that there is a region before that where only the statistically rare long free paths will give enough energy to produce many generations and the cascades the result is eventually peter out. The result is a bubble of highly ionised gas that emits RF energy as the electrical current that movement of the ions varies randomly. . Increasing the frequency of the AC supply makes things worse. A shorter time between cycles leaves less time for the ions to be neutralised after the field strength dies before the next peak comes leaving a greater seed population of ions to start the next cycle. This is one of the reasons it is common when impregnating transformers and other electrical equipment to do so in a vacuum Although this effect can take some time to produce complete failure it will very likely do so in the end Nick Rouse - Original Message - From: Ken Javor ken.ja...@emccompliance.com To: emc-p...@majordomo.ieee.org Sent: Friday, January 25, 2002 6:08 PM Subject: broadband RE from AC induction motors Do any forum members have knowledge of a mechanism by which ac induction motors (two are fan motors, one a compressor motor) can generate broadband RE from 30 - 600 MHz? This is outside my experience. Are there perhaps degradation modes that result in arcing? The motors run off three phase 400 cycle power, 115 Volts rms phase to neutral. The control system is bang-bang, just mechanical relays making connections/disconnections based on temperature and pressure inputs. The rep rate of the BB noise is variable but around 10 milliseconds. Thank you. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: 60950 - Insulation between mains and secondary with capacitors
Yes, I see a problem , Lightning spikes and the full peak mains voltage when the mains is switched on at its voltage peak will pass straight through your capacitors causing a safety hazard and may destroy the insulation of the transformer if it is not rated for this voltage. Nick Rouse - Original Message - From: Pierre SELVA To: Forum Safety-emc Sent: Friday, January 11, 2002 5:18 PM Subject: TR: 60950 - Insulation between mains and secondary with capacitors Hi forum members, I would like to know your meaning on the following : The concerned product is in the 60950 scope (EN, UL or IEC). I would like to make the insulation between the mains and the secondary without transformer, but only with capacitors (X rated). In fact, I need to use only the high frequency signals transmitted on the mains. In this case, the capacitors are considered as short circuit, and the 50 (or 60) Hz is cutted by caps. The circuit is as follow : C T1 ---| |-+ +- Mains + + Secondary part ---| |-+ +-- C C are X rated capacitors T1 is only a signal transformer (not use for galvanic insulation) My questions are : - Is this insulation correct according to reinforced insulation requirements ? - May I use only one caps for C, or 2 serial caps (in case of first default) ? - Do you see other critical points regarding 950 requirements ? Thanks a lot for your contribution, Best regards, Pierre eLABs (emc, safety and radio labs) Pierre SELVA 18 Rue Marceau Leyssieux 38400 SAINT MARTIN D'HERES - FRANCE Phone : 33 (0)6 76 63 02 58 Fax : 33 (0)6 61 37 87 48 e-mail : e.l...@wanadoo.fr ps.el...@laposte.net ==
Re: radar
I don't know if the technique is used in America but the speed cameras in the UK are triggered by radar but produce evidence by taking two pictures illuminated by two strobe pulses timed about 150ms apart. Stripes are painted across the road spaced so that between flashes a vehicle will traverse one stripe pitch for every 10mph.If the pictures show you have traversed more than 7 stripe pitches (on motorways)you will receive copies of these photos together with a summons to appear in court. Nick Rouse Jim Freeman wrote: Hi All, I apologize for being off subject but I was driving to work and noticed aCalifornia Highway Patrol officer on the opposite of the freeway an about 500 yards away. What brought him to my attention was what appeared to be a strobe light that was flashing. I have been thinking about and I was wondering if the new radar has some ways of taking pictures or if the strobe light really is the radar source. Any help would be appreciated. Thanks Jim Freeman Hi All, I apologize for being off subject but I was driving to work and noticed aCalifornia Highway Patrol officer on the opposite of the freeway an about 500 yards away. What brought him to my attention was what appeared to be a strobe light that was flashing. I have been thinking about and I was wondering if the new radar has some ways of taking pictures or if the strobe light really is the radar source. Any help would be appreciated. Thanks Jim Freeman
Re: Lasting of the CE marking
I am not sure but from what you say you seem to have missed the point that in most directives, certainly the EMC and LVD it is the individual item that must meet the current standards at the time that item is placed on the market in the EEA or taken into service there for the first time. It is irrelevant when the design was first marketed. If you have tested the design and haven't changed it and the standards you tested the design to are still current. you may carry on marketing copies of that design. When a standard is withdrawn, from that date you may not sell such items until you can show the design meets the new standards Nick Rouse - Original Message - From: Kim Boll Jensen kimb...@post7.tele.dk To: EMC-PSTC emc-p...@majordomo.ieee.org Sent: Thursday, January 03, 2002 8:54 PM Subject: Lasting of the CE marking Hi all I was just seeking through EMC LVD RTTE and MD directives for evidence of my interpretation but I couldn't find it, so can some of you help me. As I recall there are the following rules: For EMC directive you will always have to produce according to the latest harmonized standards (after dow date) For all other directives you just use the harmonized standards which was acceptable at the time of entry to the market (then you can produce the same product for decades without retesting to new harmonized standards) Please help me finding the clauses in the directives which supports this statement. But what about RTTE when new standards are harmonized where no standards was before ? Best regards, Kim Boll Jensen Bolls Raadgivning --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Fw: skinny power cords.
- Original Message - From: Nick Rouse 100626.3...@compuserve.com To: WELLMAN,RON (A-PaloAlto,ex1) ron_well...@agilent.com Sent: Friday, October 26, 2001 9:52 PM Subject: Re: skinny power cords. Earlier on in the thread it was not about arcing across the pins of a plug but about the dangers or having a power cord rated lower than the protection in the supply. Damage to the cord such as squashing it under the legs of furniture or repeated flexing or overloads in simple unfused equipment like table lights can cause overheating in the cord that will not trip out the circuit protection. Fused plugs do allow thin power cords to be used safely from supplies that have a high rated current, In the UK power outlets are on a ring protected by a 30A or 50A fuse or breaker. Nick Rouse Original Message - From: WELLMAN,RON (A-PaloAlto,ex1) ron_well...@agilent.com To: emc-p...@majordomo.ieee.org Sent: Friday, October 26, 2001 3:05 PM Subject: RE: skinny power cords. Hello all, Earlier on in this thread it was eluded that this problem was leading to the need of fused power plugs, similar to what is done in the UK. However, based on the analyses of several people, I do not see how a fused plug would of prevented the failure that Robert experienced. Regards, +=+ |Ronald R. Wellman|Voice : 408-345-8229 | |Agilent Technologies |FAX : 408-553-2412 | |5301 Stevens Creek Blvd.,|E-Mail: ron_well...@agilent.com| |Mailstop 54L-BB |WWW : http://www.agilent.com | |Santa Clara, California 95052 USA| | +=+ | Common sense is the collection of prejudices acquired by age | | eighteen. - Albert Einstein | +=+ --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: skinny power cords.
Robert Macy wrote Anyway, a little damn fuse in the plug would not have helped in this circumstance, complete waste of time, much like the main breaker was. No the fuse in UK plugs would not have helped in this case but the 34mm of creepage distance between the pins that you get in most plugs built to of the latest version of BS1363 would most certainly have done so Nick Rouse --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: skinny power cords.
Hello Gary, Sounds like your making a case for the wider adoption of the UK system with fused plugs rated to protect the power cord Nick Rouse - Original Message - From: Gary McInturff gary.mcintu...@worldwidepackets.com To: EMC-PSTC (E-mail) emc-p...@ieee.org Sent: Wednesday, October 24, 2001 5:06 PM Subject: skinny power cords. Fuses and breakers etc, are provided to protect the wiring downstream from these devices. A 15 amp breaker is allowed to have 14 AWG wire attached and run all though my house, and terminates in a 15 amp rated receptacle - parallel blade with ground pin. Why then can I plug in a computer that has only a 6 or 10 amp rated power cord? Surely, its not because the computer has supplemental fusing at 2 amps or whatever. That 2 amp fuse can't protect the wiring between it and the 15 amp breaker in my garage from prolonged operation at 15 amps. The breaker is completely happy running at that value so the wire just sits there and cooks! One would think that any cord rated less than 15 amps, would have to be terminated in a plug that doesn't mate with the wall outlet, much like a 15 amp connector plugged into a 20 amp outlet. Gary --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Power Plugs
Certainly not in the U.K. for equipment that may be sold to consumers. It is illegal to sell such equipment without a plug to BS1363 already fitted and with the correctly rated fuse in the plug. Here and in the rest of Europe the cord must have IEC colour coding. Regards Nick Rouse - Original Message - From: wo...@sensormatic.com To: emc-p...@majordomo.ieee.org Sent: Tuesday, October 02, 2001 7:05 PM Subject: Power Plugs In the EU is it legal to ship a product with an attached power cord with pig tail leads and have the appropriate power plug attached by the installer according to the installation instructions? Richard Woods --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Component ESD Immunity Testing
A reminder to anyone who carries out ESD tests on IC's Don't forget to throw away the tested sample. It is easy for IC's to survive ESD tests and appear to be normal but to have serious internal damage that will severely compromise the reliability of the unit Regards Nick Rouse - Original Message - From: Ravinder Ajmani ajm...@us.ibm.com To: EMC-PSTC emc-p...@ieee.org Sent: Monday, October 01, 2001 7:44 PM Subject: Re: Component ESD Immunity Testing I have been asked on several occasions to test some particular IC on the card, whenever there have been instances of IC failures during product manufacturing/testing. Most ICs are built to withstand an ESD event of 2 kV, and I have found this to be true in my tests. If IC happens to be OK then I try to improve the card design to reduce/eliminate the product failures. Regards, Ravinder PCB Development and Design Department IBM Corporation Email: ajm...@us.ibm.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Does anyone have any information on Rendar in England?
Rendar were taken over a couple of years back by Schurter. The traded for a while as Rendar - Schurter but have now dropped the Rendar part of the name and are just Schurter UK Ltd. They are still operating from the same factory in Bognor and still making the same products such as IEC320 plugs and sockets Their address is :- Schurter Ltd. Durban Rd. Bognor Regis West Sussex PO92 9RX U.K. Their Web Site is www.schurter.co.uk phone number form abroad +44 1243 810810 Schurter have a US subsidiary Schurter Inc. PO Box 750158 Petaluma CA 94975-158 Phone 707 778 6311 - Original Message - From: mkel...@es.com To: emc-p...@majordomo.ieee.org Sent: Thursday, August 02, 2001 4:12 PM Subject: Does anyone have any information on Rendar in England? I'm looking for contact information for a company named Rendar in England or for their rep or distributor in the U.S. Thanks in Advance, Max Kelson Evans Sutherland --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall, --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall,
Re: In-line Fuses
The UK Company Bulgin make a series of in-line fusesholders that are rated at 10A 250V when used in equipment but only 50V when directly accessible to touch. They come in sizes for fuses 5 x 20mm, 0.25 x 1 in and 0.25 x 1.25 in and in unsealed and IP66 sealed verions. See their web site:- www.bulgin.co.uk/Products/Fuseholders/In-Line_Fuseholders.html They claim to have a US distributer but I could not get that bit of their web site to work. In the UK they are distributed by the UK branch of Arrow, perhaps it is the same in the US. I have not used them so I do not know how good they are . Nick Rouse - Original Message - From: brian_ku...@leco.com Subject: In-line Fuses We have an application where an In-Line Fuse would be an easy fit to a problem. The fuse and holder would be added to an existing internal cable harness in a piece of Lab Equipment (EN61010-1 for safety). The wire that needs the fuse has 120 Volts ACrms and we need to limit the current to 5 amps. The 120 volts derives from the secondary of an isolation/step down transformer who's primary is attached to the 230Vrms mains. While looking for a fuse holder I'm finding that I can't find one that is rated for use over 32 volts. Does anyone know of a manufacturer who makes an In-Line Fuse Holder that meets the safety requirements and is rated for 120Vrms? Thank you for your help. Brian Kunde LECO Corp. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall,
Re: Products Electrical Ratings De-rated for Eurpoean Branch Circuits
Peter Tarver wrote in reply to my comment The rating of a UL rated fuse is more or less the current at which it blows. The rating of a fuse to IEC 127 (used throughout Europe) is more or less the working current of the fuse and the circuit it protects This may or may not be true. Last I looked, UL Listed miniature fuses (typically 1 X 1-1/4in cartridge size) and branch circuit protection fuses are required to carry 110% of their rated current for a minimum specified time and 100% continuously; Listed microfuses are required to carry 100% of current continuously. For a UL Recognized fuse (including 5 X 20mm cartridge sizes, of which you most likely refer), this is not necessarily the case, though it may be. Thus, the rating of a fuse ... is more or less the working current of the fuse is as true for a UL Listed fuse as it is for an IEC 127 fuse. For Recognized Component fuses, any deviation from the base requirements for Listing is rationale to allow only Recognition. These base requirements include, but are not limited to: physical dimensions, current carrying capacity, calibration or time-to-open characteristics, time delay characteristics for time delay rated fuses, etc. There is a substantial difference in the rating of UL and IEC127 fuses. UL listed fuses such as 1 x 1¼ in fuses are required to blow at 135% of rating in one hour. IEC127 fuses such as 5 x 20mm are required not to blow in one hour at 150% of rating. The difference in must blow and must not blow means that the actual current the fuses blow at is very much wider than the 135% to 150% ratio. The first must blow current mentioned in IEC127 is at 210% of rating. With fuses only sure to hold at 110% percent of rating you would not use a load with a nominal load of 100% of the circuit rating as small deviations upward of nominal may take out the fuse. That is why it is common to derate branch circuits in the US. This is not needed with IEC127 fuses. It is quite reasonable to have the nominal load equal to the rating of the protection. My characterisation of the two rating systems being blowing current and working current may be fairly crude but it is not that far from true I do not have the figures for circuit breakers to hand but I believe there is a similar disparity in European and US ratings. The current carrying rating of European wiring regulations obviously reflect these differences. If fact these differences might have something to do with the differences in the rating of IEC320 C13 C14 connectors in the US and Europe discussed in this forum recently, 15A in the US 10A in Europe. Peter further wrote One is left with the question: are fuses used throughout Europe as an integral part of mains circuit protection? By this I include the power supply cord as an extension of the mains, whether or not it is included by definition or is absolutely correct in everyone's perspective. There is certainly a move towards circuit breakers and away from fuses but fuse protection is still being used in new domestic premises and some industrial ones also and there is a huge installed base of fuse protected wiring. The latest issue of the UK wiring regulations have tried to push the move to circuit breakers by allowing smaller wire to be used in circuit breaker protected circuits of the same rating as fuse protected circuits to reflect the closer ratio of must break to must hold currents of circuit breakers. The UK ring main system is unusual if not unique. Because the ring main will be protected by a 30A or 50A fuse or breaker and the plugs and sockets on the ring rated at 13A (despite their vast size) and the power cord possibly rated considerably less than this, the fuses in BS1363 plugs used in the UK are an essential part of electrical safety in the UK. One is left with the question: are fuses used throughout Europe as an integral part of mains circuit protection? By this I include the power supply cord as an extension of the mains, whether or not it is included by definition or is absolutely correct in everyone's perspective. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall,
Re: Products Electrical Ratings De-rated for Eurpoean Branch Circuits
Hello Glenn, Two things complicate this question. One is specific to the U.K. In the UK all domestic and very many commercial and light industrial use a ring main for all socket outlets and therefore we do not have spurs with ratings. UK plugs have fuses in them because the protection on the ring main is much higher than the rating of the plugs. The second applies to all of Europe and conncerns fuses and other circuit protection. The rating of a UL rated fuse is more or less the current at which it blows. The rating of a fuse to IEC 127 (used throughout Europe) is more or less the working current of the fuse and the circuit it protects. Thus circuits are used right up to the full rating of fuse protecting them Nick Rouse - Original Message - From: Lesmeister, Glenn glenn.lesmeis...@compaq.com Subject: Products Electrical Ratings De-rated for Eurpoean Branch Circuits Does anyone know if it is common practice or otherwise required to de-rate products in Europe to 80% (or some other %) of the rating of the branch circuit as is done in the US? Some product standards (such as 61000-3-2) apply to products rated up to 16A, so it would appear that products can be rated up to the branch rating. If this is the case, would it be acceptable to exceed the rating by 110% (as allowed by 60950) and still be usable on that branch circuit? Regards, Glenn Lesmeister --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall,
Re: CE marking for Small quantities of a gas appliance
Hello Nick, Has the scope of the directive changed since 1990? because if not, then the scope would seem to be a fair bit wider than you suggest Article 1 1. This directive shall apply to : -appliances burning gaseous fuels used for cooking, heating, hot water production, refrigeration, lighting or washing and having, where applicable, a normal water temperature not exceeding 105°C, hereinafter referred to as 'appliances'. Forced draught burners and heating bodies to be equipped with such burners will also be considered as appliances. - safety devices, controlling devices or regulating devices and sub-assemblies , other than forced draught burners and heating bodies to be equipped with such burners separately marketed for trade use and designed to be incorporated into an appliance burning gaseous fuel or assembled to constitute such an appliance, hereinafter referred to 'fittings'. 2. Appliances specifically designed for industrial processes carried out on industrial premises are excluded from the scope defined in paragraph 1. 3. For the purposes of this Directive, gaseous fuel means any fuel which is in a gaseous state at a temperature of 15°C under a pressure of 1 bar. Although the Directive gives in article 8 two means of certification of conformity, 1) type approval followed by a choice of four methods to show conformity to type for series production. 2) EC verification by unit for one-offs and small numbers. the problem as far as Dan is concerned is that both means require the services of a notified body and cannot be self certified. If the directive is applicable there would not seem to be any cheap legal way of getting a few appliances into Europe. I stress again this is not an area I have any experience in and the directive may have been modified but if the directive stands its wording is fairly unambiguous. Regards Nick Rouse Original Message - From: Nick Williams nick.willi...@conformance.co.uk To: Dan Teninty dteni...@dtec-associates.com Cc: Emc-Pstc@Majordomo. Ieee. Org emc-p...@majordomo.ieee.org Sent: Sunday, April 01, 2001 8:22 PM Subject: Re: CE marking for Small quantities of a gas appliance The Gas Appliances Directive contains two different routes which are alternatives to the full type approval route. These are the 'verification' routes and they are intended for exactly the situation you describe. There are some brief details at http://www.conformance.co.uk/CE_MARKING/ce_gas.html Before you get into this, however, decide whether or not the product is actually a gas appliance within the meaning of the directive. Basically, if it not used for room heating (and rooms included industrial spaces such as warehouses and aircraft hangars) or for cooking in a domestic or commercial kitchen, it is outside the scope of the directive. If this is the case it will almost certainly be within the scope of the Machinery Directive and you simply treat the gas aspects as any other hazard (unless you have a plenum which contains an un-ignited gas-air mixture, in which case the ATEX directive may apply). The Machinery Directive may apply to it even if it is within the scope of the GAD, as may the LVD and EMC directives. However, unless the GAD (or ATEX) applies, the equipment will only require self certification. Incidentally, you should note that the GAD test houses tend to be picky about the EMC immunity performance of the control system and simple compliance with the EMC directive standards may not be enough to satisfy them. We have done exactly this sort of work in the past, and I'd be happy to give you some more advice if you'd care to contact me privately with some more details of the equipment. Regards Nick. At 12:20 -0800 30/3/2001, Dan Teninty wrote: One of our clients wants to ship a small (less than 10)quantity of an industrial gas appliance into the EU. Since the quantity is limited and a full blown approvals submittal would be cost prohibitive, is there a provision to get third party review of a product on site and is it even required? This is a factory built product that is delivered on a truck, hooked up to gas and electric supplies. We can assist the client in identifying the applicable standards, reviewing the product for compliance and issuing a DofC. This would be sufficient for some products to affix a CE sticker, but I'm not sure in this case. Would appreciate any input from the group. Regards, Daniel E. Teninty, P.E. Managing Partner DTEC Associates LLC Streamlining the Compliance Process 5406 S. Glendora Drive Spokane, WA 99223 (509) 443-0215 (509) 443-0181 fax --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line
Re: 230 Vac or 240 Vac?
George You are right that the UK still generates electricity to give single phase supplies centred at 240V. This is despite changing its nominal to 230V to harmonise with the EU. It is allowed a variation of +10% and -6%. of the nominal 230V (216 - 253) but unlike true 230V countries it is habitually at the top end of that range. I have frequently seen voltages at the socket of 245V to 247V As well the effect you mention of high voltage at times of low usage there is also the effect of neutral offset caused by unbalanced phase loads. UK supplies to domestic and commercial premises use a balanced three phase and neutral cable and connect premises to one of the phases and neutral. In a housing estate every third house is connected each phase.A large load on one phase will cause a voltage drop down the neutral. Neutral to earth voltages of 10 to 15 volts are not uncommon. Because this voltage is at 120° to the other phases a half its value will be added to the phase to neutral voltages of the other phases. It would not surprise me if occasionally the voltage exceeded 254V Another thing to remember about countries with a high supply voltage is that the voltage spikes are correspondingly higher as those generated on the high voltage transmission lines are transformed down by a lower ratio Nick Rouse - Original Message - From: geor...@lexmark.com To: gelf...@memotec.com Cc: emc-p...@majordomo.ieee.org Sent: Friday, February 02, 2001 7:30 PM Subject: Re: 230 Vac or 240 Vac? David, Here is my understanding based on an earlier discussion on this forum and some of our business experiences. The agreement amongst many high volt countries was on a 220-240V range. This implies a 230V nominal. The 240V countires agreed, but never changed their nominals, as this would have involved serious changes to their power generation equipment. Their reasoning was that a product rated at 220-240V is required under IEC 60950 and like standards to be tested up to 6% over rated voltage, i.e. a max of 254V. They assumed they could deliver power to the end users within this range without changing their nominals. I'm beginning to doubt this assumption as we have had numerous reports of our direct plug-in external power supplies running hot in two geographies only, viz. the U.K. and Australia/New Zealand. Since we have specified and tested up to 254V without problems, it is my belief that the end users may be seeing over 254V on low periods of the day. High usage periods result in more IR drop along the transmission paths, and reduce the end voltage. This is just my opinion based on my experiences. George Alspaugh Lexmark International Inc. gelfand%memotec@interlock.lexmark.com on 02/02/2001 10:56:22 AM Please respond to gelfand%memotec@interlock.lexmark.com To: emc-pstc%majordomo.ieee@interlock.lexmark.com cc:(bcc: George Alspaugh/Lex/Lexmark) Subject: 230 Vac or 240 Vac? Group, I seem to remember that Australia was changing their nominal voltage from 240 to 230 V. Is this true? Are there other countries that have nominal voltages of 240 V? I want to determine the maximum voltage for leakage current tests. Best regards, David. David Gelfand Regulatory Approvals Memotec Communications Inc. Montreal Canada --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Beta Shipments
No. Paul, there are none. There are no exceptions in the EMC directive or the low voltage directive for beta testing and no way of getting around the regulations by any label of non-conformance. In the EMC directive any relevant apparatus placed on the market or taken into service must meet the regulations and have a CE mark and Declaration of Conformity. The guidelines issued by the commission show that both terms have a wide interpretation. An apparatus covered by the EMC directive is put into service when it is first used [in the EEA territory] Placing on the market is first making available, against payment or free of charge, ... for the purpose of distribution and/or use in the EEA Making available means ... transfer of ownership or physical hand-over ... to the final customer or user in a commercial transaction ... (sale, loan hire, leasing, gift or any other type of commercial legal instrument) The Commission's guidelines state that placing the product on the market does not concern the display of the product at trade fairs and exhibitions It may not be in full conformity with the provision of the EMC directive, but this fact must be clearly advertised next to the apparatus being exhibited Note this exception concerns only placing on the market not taking into service and does not even mention switching it on and has no mention of going to a customer's site An anomaly here is the UK implementation of the directive. Since the directives by themselves do not have direct force of law anywhere they need to be implemented into national law in each Community State. In countries like France and Germany the EMC directive is transcribed almost verbatim into the national law In the UK a fairly liberal interpretation of the directive is used. In the UK 1992 Electromagnetic Compatibility Regulations SI 1992 No. 2372 the term supply is used instead of place on the market. The question of trade fairs and exhibitions, not mentioned in the directive and therefore not in the French and German laws is written directly into the UK law. supply is defined as first making available of relevant apparatus for a consumer in the Community including, without limiting the generality of the foregoing, offering to supply, agreeing to supply, exposing for supply and possessing for supply such apparatus ... provided however that relevant apparatus shall not be regarded as having been supplied by reason only of its having been displayed at a trade fair or exhibition ... This is not too different from the directive as elaborated by the Commission but the point at which the UK law strays significantly from the Directive and the Commission guidelines is in the question of taking into service. In clause 6 of the UK regulations it says ... relevant apparatus shall not be regarded as having been taken into service by reason only of its having been operated by or on behalf of the manufacturer at a trade fair or exhibition or by a supplier for demonstration purposes This last phrase would seem to clear the way in the UK for a sales rep to take a non-compliant demonstration model around to customers sites and demonstrating how it works. However I would say that any beta test in the form of a trial to see how it performs under field conditions would exceed the most generous interpretation of UK law irrespective of whether a company representative is present and would be way outside the law in most of the rest of the Community where first use implies taking into service. The Low Voltage directive is even tougher. There is no trade fairs and exhibitions clause. If the equipment is switched on by the customer or your sales rep it must be electrically safe and be CE marked for the Low voltage directive Regards Nick Rouse - Original Message - From: O'Shaughnessy, Paul paul_oshaughne...@affymetrix.com To: 'Lou Guerin' lgue...@littlefeet-inc.com; EMC-PSTC emc-p...@majordomo.ieee.org Sent: Wednesday, January 17, 2001 10:40 PM Subject: RE: Beta Shipments Can anyone direct me to the EC rules which govern beta site installations? For example, what if a contract is signed with the beta site, specifying that the unit is not yet evaluated, and specifying terms of beta testing and timeframe. Would that qualify as under the control of the manufacturer? Having your own people run the thing, even at a remote site, rather defeats the intention of a beta test, and it's a bit hard to believe that this is how it's really done. Thanks, Paul O'Shaughnessy Affymetrix, Inc. Lou Guerin wrote: For Europe you have less leeway, you can show the product at a trade show with a PROMINENT label declaring that the product has not been evaluated for compliance to the appropriate LVD and EMC directives. The directives prohibit the placing on the market or putting into service any product that does not conform to the directives. This only allows you to demonstrate the product at the customer's site if it is always under
Re: How does RF travel through outer space?
in other areas that would effect the propagation of light such as the variation over cosmic time of the principal 'constants' or free space being slightly dispersive (like a prism) but these are highly speculative and have, as far as I am aware, no experimental backing. Heterodox thinkers of very widely varying credibility have challenged most established theories at one time or another. Who knows one of them may be the prophet of the scientific future but the odds are against them. If 11 dimensional super string theory lives up to its promise and becomes the master explanation of all physics the description of light will look very different but it must reduce to something close to the present formulation in most experimentally accessible regions if it is to agree with all past experiments. The inverse square law only applies to distances that are large with respect to size of the source. It does not imply any loss of energy, only the spreading out of that same amount of energy over a larger volume. Imagine the energy in a spherical shell 1cm thick at a radius of say 10m from a small antenna or light bulb and then imagine that this energy propagates out radially in all directions so that some 90ns later it occupies a spherical shell still 1cm thick but 40m radius. Since the radius has increased by a factor of 4 the surface area of the shell will have increased by a factor of 16 (A = 4 .pi .r²) Since the thickness is the same the volume over which this energy is spread out has increased 16 fold. If no energy has been lost and all of it uniformly spread out the energy per unit volume must have been reduced by a factor of 16 giving the inverse square law relationship. Note that this is not a peculiarity of electromagnetic radiation but applies to any spherical spreading out of energy such as sound from a suspended loudspeaker an heat conducting through a solid from a point source. Conversely in does not apply even to electromagnetic radiation from a source that is large with respect to the measurement distance. The field from a long wire radiator will fall as 1/r for distances short with respect to the wire length and does not fall at all from a flat plate radiator at distances short with respect to the plate dimensions.(assuming all points on the radiator in phase or distances small with respect to the wavelength) Followers of this forum will know that close to the irregular shaped equipment they have to deal with, the radiation pattern can change in the most complicated way. I know this does not count as anything like simple but simple sounding questions often have complicated answers as Benoit Mandelbrot found when he asked 'how long is the coast of Britain?' I hope you can distil some simple if simplified answers that will satisfy your class. Nick Rouse - Original Message - From: brian_kunde brian_ku...@leco.com To: emc-pstc emc-p...@majordomo.ieee.org Sent: Thursday, November 30, 2000 8:50 PM Subject: How does RF travel through outer space? Hello, I'm sorry if this is too simple of question... How does RF travel through outer space?. I will be teaching a class in which this question will come up. I want to be prepared with all the basic science behind this principal. I need an explaination that is simple and easy to understand. People seem to have no problem understanding how waves can travel through mass such as a body of water but can not understand how it can travel where there is no mass. I also understand that there is a lot of debate over how Light travels through space (photons and all). Also, I understand that RF signals degrade at a rate of 1/distance(squared). What force is causing this attenuation? Try to keep it simple for my audience it not all that technical. Appreciate the help. Please forgive any improper punctuation or word misuse. Brian --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: safe voltage limits for cattle ( cows horses etc)
Chris Maxwell wrote There is no such thing as the Bovine/Equine Equipotential Directive. No, there isn't, but the Low Voltage Directive (73/23/EEC) in its principle protection requirements in Article 2 says:- The member states shall take all appropriate measures to ensure that electrical equipment may be placed on the market only if, having been constructed in accordance with good engineering practice in safety matters in force in the community, it does not endanger the safety of persons, domestic animals or property when properly installed and maintained and used in applications for which it is made. I do not know of any harmonised standards relevant to this directive that refer to domestic animals but on the other hand I do not remember in any of the standards that specify hazardous voltages that they specifically state that these levels are only for the protection of humans. Nick Rouse --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: EN 61000-3-2/A14
Fred, The dow is the date at which conflicting standards must be withdrawn. For an ammendment it means the part of the old standard that conflicts with the ammendment. From the doa until the dow you may use either the old unamended standard or the new ammended version. After the cross over period you may use only the new amended version. Nick Rouse - Original Message - From: Friedemann Adt a...@viewsonic.com To: h...@jyske-emc.com; emc-p...@majordomo.ieee.org Sent: Friday, October 06, 2000 6:56 PM Subject: Re: EN 61000-3-2/A14 I tried to refresh my memory about quoted abbreviations but even using the Official Journal's search engine I got not beyond 'DOW Jones Industrial'. Thus I like to appeal to any merciful soul out there to straighten me out.. dow: is the date at which the standard is enforced and therefore the date at which product being brought onto the market has to comply ? Thank you Fred Adt compliance reliability manager a...@viewsonic.com phone (909) 444-8958 Helge Knudsen h...@jyske-emc.com 10/06/00 02:50AM Hello group EN 61000-3-2/A14 was ratificated 2000-10-03 with the following dates: dor: 2000-10-03 doa: 2000-12-01 dop: 2001-01-01 dow: 2004-01-01 It is expected that the amendment will be announced in Official Journal before 2001-01-01. Best regards Helge Knudsen Jyske EMC Denmark --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Fw: Overcurrent Protection: One or Both Sides?
From: Nick Rouse 100626.3...@compuserve.com To: wo...@sensormatic.com Sent: Saturday, October 07, 2000 7:44 PM Subject: Re: Overcurrent Protection: One or Both Sides? Hello Richard No, there is only one fuse in the standard BS1363 mains plug . It is in the live side and the plug is not reversible. The neutral of UK low voltage distribution systems is earthed at the local distribution transformer (and sometimes at additional points). In all but remote rural areas the three phases are distributed along the road together with the neutral and one phase and the neutral fed to each house so that every third house is on the same phase. The purpose of the fuse is to not to protect the house wireing or the appliance but to protect the mains cord between the plug and the appliance. This is required because nearly all houses are wired on the ring main system. All sockets on the same floor are connected to a ring of heavy cable. This ring is protected by a fuse or circuit breaker with a rating appropriate to the heavy cable. The lower rated mains cord therefore needs separate protection. This system has the advantage that low powered appliances can be fitted with cheaper and less clumbsy power cords and be safe plugged into and socket. Damaged or overloaded mains cords are a common source of hazards and not always well dealt with in other systems Fuseing the neutral is stongly frowned on in UK safety circles. For UK use, you can afford it use two pole circuit breaker, else fuse only the live side. Nick Rouse - Original Message - From: wo...@sensormatic.com To: emc-p...@majordomo.ieee.org Sent: Friday, October 06, 2000 8:59 PM Subject: RE: Overcurrent Protection: One or Both Sides? You are correct that fuse protection in the British cord is for fault protection of the building wiring. I could be wrong, but I thought that there were two fuses in the plug. Perhaps others can comment on this. Fusing of the neutral is a messy issue. If you use only one fuse, it cannot be in the neutral. If you use a fuse in the line and a fuse in the neutral, the warnings you indicated must be present. Richard Woods -- From: jradom...@clare.com [SMTP:jradom...@clare.com] Sent: Friday, October 06, 2000 3:15 PM To: emc-p...@majordomo.ieee.org Cc: wo...@sensormatic.com Subject: RE: Overcurrent Protection: One or Both Sides? Richard, To prevent unexpected hazards to service persons, that fuse may not be place in an identified neutral line. It is permitted to place a fuse in an identified neutral line provided that the live side is fused + special information/marking is given Having said that, the UK and some other parts of the world have a power mains setup that allows for heavy earth fault currents from either pole. So they use dual fused power cords. Could you give an example of dual fused power cord? The British AC plug is equipped with just one fuse connected to the L side. But as I understand this system is used to protect their unique building wiring, not the equipment. John Radomski Compliance Engineer Clare Corp. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Date of withdrawal
I don't know any French but if it is the French implimentation of the Machinery directive it would not cotain any EN numbers. The Machinery directive is a New Approach directive and they never specify particular standards. It specifies routes to compliance that refer to harmonised standards. Standards adopted by CEN for the Machinery Directive and the title of which have been published in the OJ become Harmonised standards. The dates of application and dates of withdrawal (of conflicting standards) that are published with these standards determine which constitute the current harmonised standards. By this means the directive can be kept technically up to date uniformly across the EU without having to ament the law in each state of the EU. Remember that it is each item of equpment that must meet the requirements on the day it is placed on the market or taken into service in the EEA. The fact that the design meet the requirements when first sold does not necessarily mean you can sell it in Europe now. The Frech implimentation of the Machinery Directive (if that is what it is) is included in your documentation is there because that is the thing that has force of French Law. All the other standards only become legal requirements of French Law by virtue of requirement in that implimentation to meet harmonised standards. - Original Message - From: Veit, Andy andy.v...@mts.com To: emc-p...@majordomo.ieee.org Sent: Monday, October 02, 2000 6:17 PM Subject: Date of withdrawal Hello- I am reviewing CE documentation for a product of ours that, until recently, was manufactured in France. I have been able to find the effective dates and dates of withdrawal for all standards listed in the support documentation I have, but I ran across something that has me totally stumped. I have a 1997 document from Bureau Veritas that documents conformance to Decree 92-767, specifically to Article R 233.83 of the Code du Travail. Decree 92-767 appears to be French legislation for the adoption of the Machinery Directive. It does not specify any reference EN documents. Can anyone tell me what Decree 92-767 was? And more importantly, if I can use it as a supporting document for EN 60204-1? My hunch is that I can't, but obviously I need some facts. EN 60204-1:1992 has a date of withdrawal of July 1, 2001 anyway. Thanks in advance- -Andy Andrew Veit Systems Design Engineer MTS Systems Corp Cary, NC --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Getting Started
Hello Tin, This is a difficult point but I think on strictly legal terms of the UK implementation of the EMC directive my old friend and colleague Chris Dupres is right, although I would strongly caution against trying it unless you are very sure your equipment does not cause interference. It must be remembered that the EMC directive itself does not carry the weight of law anywhere. However all signatories to the Treaty of Rome and the European Economic Area Agreement are bound by those documents to pass into the domestic law of their states the same or equivalent legislation. Some countries like France have done this by passing verbatim into law the National language version of the directive and issuing additional regulation on matters not covered by the directive such as how it will be policed and what the penalties are for breaking the law The UK however passed a single item of legislation to cover all aspects in the form of Statutory Instrument 1992 No 2372 The Electromagnetic Compatibility Regulations. In these the EMC directive is rewritten and a number of wrinkles are added that are not in the EMC directive. It is open to the Commission or any other aggrieved state to take the UK to the European Court of Justice on the grounds that we have not fully implemented the directive, as bound by treaty, but they have not done so and UK law stands. Examples of such wrinkles are the exclusion of electromagnetically benign equipment in clause 17. In could be argued that Chris' example of a convection heater does not even need a CE mark let alone testing. In Clause 8 Educational equipment only has meet the protection requirements outside the bounds of the educational establishment. In Clause 13 large fixed excluded installations do not have to show conformance for the whole installation if the parts conform and the installation is put together according to the instructions for EMC conformance for each part. As to whether the standards route requires testing the relevant clause is 37 The conformity assessment requirements are complied with pursuant to the standards route to compliance if the manufacturer has applied an applicable EMC standard which makes, or all applicable EMC standards which make, complete provision in respect of the apparatus What it does not say is it must be tested to and pass all EMC standards that have been adopted for EMC by CENELEC and had their titles published in the OJ. It has been argued that a manufacturer may claim that a certain standard is not necessary to make complete provision for the equipment. (for instance ESD test for equipment that only ever operates completely immersed in water) The word applied is also open to interpretation. Close reading of some of the standards give levels to be met and means to measure these levels but do not explicitly say to meet this standard thou shalt carry out these tests. Although these arguments are very tenuous there is some backing from the DTI, the department with responsibilities for EMC. Although the guidelines give no hint of this interpretation they did issue an earlier document titled Minimising the cost of compliance with the EMC directive or something very similar. Unfortunately I cannot lay my hands on it at the moment but it did strongly imply that the manufacturer could decide which standards made complete provision for the equipment. This document caused quite a stir at the time but has not to my knowledge been officially retracted. There is a political background to this. Margaret Thatcher after having initially been enthusiastic about the EU as a wider stage on which to display her glory, turned against the EU when the other leaders did not bow down to worship her as the second coming of Churchill and had the blind impertinence to disagree with her. In a huff she gave orders to minimise all EU influence on the UK and this document was one of the results. (yes I know my political prejudices are showing but it is satisfying to let off a little spleen now and than) Having said all this and agreed with Chris that this is the UK law I strongly recommend you confine these ideas to arguments over a pint of beer after work and if you want to use the harmonised standards route, use all of them and test to them and if you want to skip or modify one of the standards produce a TCF and get a competent body to sign and take responsibility. If your equipment does actually cause interference and you are taken to court the only thing to stand between you and a hefty penalty (and remember the signatory of the DOC bears personal liability) is an argument of due diligence If your equipment fails because of an aspect that there is a specified test for and you deliberately decided not to test for you have a very difficult case to make. If you think you could make such a case I suggest your talents would be much more profitably employed in the law than in being a compliance engineer. Nick Rouse - Original Message - From: tinb
Re: Getting Started
- Original Message - From: Nick Rouse 100626.3...@compuserve.com To: FRIES fr...@amcomm.com Sent: Saturday, September 30, 2000 9:49 PM Subject: Re: Getting Started - Original Message - From: FRIES fr...@amcomm.com To: emc-p...@ieee.org Sent: Friday, September 29, 2000 3:35 PM Subject: Getting Started Dear Group, I'm just getting started in the world of EMI and would like to ask a few questions. I'm not sure if I should be going the TCF route or the Standards Route. The company that I work for manufactures products which have many variants. 1) Is it EC law that a manufacturer must perform EMI testing before applying the CE mark? Very strictly speaking No but in practice yes in almost all practical cases. If you could show by theoretical grounds that a piece of equipment neither caused or was susceptible to interference or had results from very nearly identical equipment that met the standards by a wide margin and could persuade a competent body of this fact and get him to sign the TCF that gave these augments you could legally apply a CE mark on the basis of that TCF. In practice however, interference being such sneaky unpredictable stuff, you would only have a chance of so convincing a competent body in very exceptional cases since he would bear legal liability for results of signing of the TCF if he had not shown competence and diligence. Such people tend to be a cautious breed. 2) If a manufacturer follows the Standards Route, does EC law require each variant to be tested? Yes if there is any possibility that the variants may have different EMC characteristics. This is one of the great advantages of the TCF route. In you can persuade the competent body that a particular variant is the worst case or that tests on a subset of the variants cover the EMC properties of all variants you can greatly reduce the burden of testing. 3) If, when testing, the limit is exceeded, can the CE mark still be applied? If you are using the harmonised standards route clearly no. The application of the CE mark has the legal effect of being a statement by the manufacturer that the equipment meets the requirements of all European directives that require such marking and are applicable to that product. To place equipment on the market, or to take it into service in the European Economic Area with an invalid CE mark is a serious offence. If you take the TCF route the answer is again theoretically you might be able to, but in practice it is most unlikely. The competent body only has to sign that the equipment meets the fundamental protection requirements of clause 4 of the directive and these are expressed in simple qualitative terms. The competent body is theoretically not bound by any standards, tests or measurements and can accept any evidence he judges valid and can ignore any evidence if he is convinced that the protection requirements are met. In practice however they most unlikely to sign a TCF if the equipment fails one of the standards unless there are very exceptional circumstances (like for instance if the equipment by its nature can only be used in locations remote from any other equipment.) 4) Are the services of a Competent Body required in order to put together a TCF or can the manufacturer do that on his own? No. You are in theory free to do all the work yourself and take it along for him to sign on the dotted line. However, since the main reason for using the TCF route is that you don't want to use the straight harmonised standards, it is likely that the TCF will contain some arguments as to why the fundamental protection requirements can be meet by some means other than straightforward application of the harmonised standards. It will be down to his judgement as to whether these arguments are valid. It is a bit risky to present these arguments to him cold. It is a much better idea to contact your chosen competent body before you start any testing and get an idea of what he will accept and what format he will want the TCF in. He may well have some pre-written paragraphs available for a fee that will allow you to boilerplate together a TCF that works out cheaper than doing it all yourself. Hope this Helps Nick Rouse Thanks in advance, Joseph C. Fries --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society
Re: Test voltage for products to the U.K.
Hello Raymond I do not have access to the memo but I can certainly assure you that it is the case. I have just measured the voltage as I sit here and it is 242V. The nominal change was all to do with harmonisation within the European union. The old supply regulations allowed the public supply to be 240V + 6% -10%. Because the committee that dealt with implementing the harmonisation was packed with representatives of the electricity generation industry and had few representative of manufacturers of voltage sensitive equipment such light bulbs, the path for harmonisation was that which suited the electricity suppliers. They simply declared that the supply voltage was 230V with a tolerance of +10% and -6% . If you work out the sums you will find that the new allowable range is almost identical with the old. When the appointed change over day came, numbers changed on paper but that was all. Not one generator setting was changed and not one transformer tap was changed. I have a friend in charge electrical supply in our local region and he tells me that they have no intention of changing in the near future. Even new supply equipment is designed to deliver 240V. To made this situation worse, some other European countries went the other way and declared a supply that was and remains 220V to be nominally 230V. We now have light bulbs for sale in Europe that are marked 230V but designed to work with 240V and light bulbs marked 230V but designed to work with 220V and nothing to tell them apart. Get them the wrong way around and in one case you get a brilliant light that dies in about 100 hours and in the other a light that lasts almost for ever but is ridiculously dim and inefficient. Vive! European Unity Nick Rouse - Original Message - From: raymond...@dixonsasia.com.hk To: emc-p...@ieee.org Sent: Tuesday, August 01, 2000 10:52 AM Subject: Test voltage for products to the U.K. A few years ago, BEAMA or other similar body has issued a memo to public laboratories about testing voltage for products selling in the U.K. The memo says the U.K. mains is still 240Vac although the rated voltage is agreed to be 230Vac and the products have to be taken care the safety at 240Vac. Can anyone tell me where I can find a copy of this memo and if there is any updated version to replace this one. Thanks and regards, Raymond Li Dixons Asia Ltd. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: 8591EM monitor output
Mark
You forget the most important difference from which PAL takes its
name. The alternating phase of the colour subcarrier each line. To overcome
the colour errors that reflections cause in the NTSC system, the PAL system
puts a 180° phase shift in one of the two chrominance modulating components
each line. In the receiver a one line period delay line, originally an
acoustic
glass delay line but now done digitally, is used to average the colour
signal
over two lines. This means that phase shifts caused by reflections and which
last for more than 128µs cancel out. This reduces vertical colour resolution
but since horizontal colour resolution has been filtered down to reduce the
chrominance bandwidth this is not a very peceivable degradation and well
worth it for the colour stability. This better system was the result of
being
late into colour television system after North America had found the
problems, It's the second mouse that gets the cheese! A result of this
system
needing a very accurate line delay (to within small fractions of a
subcarrier
period) is that both the vertical and horizontal synch locks are very tight
on
monitors and recievers built for PAL colour and even if you go in at
baseband video via the SCART socket found on most sets, they will not
lock up the NTSC derived baseband video as monitors used to do in
monochrome days. I used to work designing telvision equipment such as
standards converters and it is no small problem.
Nick Rouse
- Original Message -
From: CARTER
To: 'Tony J. O'Hara' ; Bailey, Jeff jbai...@mysst.com
Cc: 'emc-pstc'
Sent: Tuesday, July 25, 2000 10:47 PM
Subject: RE: 8591EM monitor output
The differences between PAL NTSC go way beyond modulating RF. Even at
baseband, the monitors will be different one may not work with the
other's
signal. The Frame rate, or vertical interval is different - NTSC based on
North American AC at 60 Hz, as opposed to European 50 Hz, and the
Horizontal
sync is different, as a result of being harmonically related to the
vertical
sync. There is an issue (probably not with the signals in question) with
the
color sub-carrier frequency offset from the video carrier, and the fact
that
(because of the aforementioned) the video (baseband) bandwidth for PAL is
much wider than NTSC. A monitor may work with the other format if it is a
little forgiving (has some slop built into the sync'ing circuits). Give it
a
shot with whatever is on hand, then go shopping if need be.
IMHO
_\\|//_
(' O-O ')
ooO-(_)-Ooo
Mark Carter
AM Communications, Inc.
car...@amcomm.com mailto:car...@amcomm.com
Voice: 215-538-8710
Fax: 215-538-8779
-Original Message-
From: Tony J. O'Hara [mailto:tonyoh...@compuserve.com]
Sent: Tuesday, July 25, 2000 12:24 PM
To: Bailey, Jeff
Cc: 'emc-pstc'; 'brian.mcauli...@tellabs.com'
Subject: RE: 8591EM monitor output
A modulator for PAL is different than NTSC! PAL receivers use different
frequencies and I also think there are other differences!) . However, I
would assume that if you're in a locality that has PAL receivers then you
should be able to easily get a PAL modulator.
Remember also, that most new (last 5 years or so) receivers (at least US
NTSC ones) have a base-band video input (making them also a monitor!),
then
you wouldn't need a RF modulator!
Tony
Colorado
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Australian Compliance
Austalia will not accept CE marking although most of the Austailian AS 3100 and AS3300 series standards are based technically on IEC standards in a similar way to many of the EN series used in CE marking. On a wide range of domestic equipment there is mandatory testing, assessment and certification under the Approval of Electrical Appliances Scheme. They are also bringing in a framework for EMC regulation and emissions standards for ITE will be the first stage. Again the standards, although local are based on international ones Nick Rouse
CE marking for replacement parts
for computer systems, micro- processor cards, central processing unit cards, electronic mail cards, telecommunication cards, etc. * control cards, cards for regulating industrial processes, etc. * modular numeric control equipment for: - machine tools - lift controls * PC disk readers; * electricity supply units, where they take the form of autonomous equipment * battery chargers * electronic temperature controls * DIY kits (DIY kits must be designed to ensure compliance with the protection requirements when the parts of the kit are assembled in accordance with the manufacturer's instructions) Components performing a direct function and placed on the market for distribution and/or taking into service are considered apparatus within the meaning of the meaning of the EMC directive. The EMC Directive applies to them. I therefore conclude that by the Commissions interpretation your items will not need to be CE marked themselves if they were supplied and installed by your service organisation but would if they were sold to the general public via a retail outlet. The in-between arrangement of the items being purchased from you or your agent by your customer for fitting themselves seems a grey area. The EMC directive does not mention repairs or spare parts explicitly and neither do the new guidelines. The UK implementation of the Directive does however. Regulation 14 of Statutory Instrument 1992 No. 2732 states that: (1) Subject to paragraph (2) these Regulations do not apply to spare parts. (2) Nothing in this regulation shall be taken in to affect the application of these Regulations to apparatus into which a spare part has been incorporated (3) In this regulation 'spare part' means a component or combination of components for use in replacing parts of electrical apparatus. The UK Regulations also, in regulation 16 specifically exclude second hand apparatus provided it has not been subject to further manufacture. however the definition of manufacture in regulation 3 (2) specifically excludes repair Thus from a UK point of view in your cases 1 and 2 both the replacement components (as spare parts) and the repaired systems (as repaired second hand equipment) are excluded from the regulations. Your case 3 is a bit of a problem if the customer buys and fits the options themselves. Had your service organisation fitted the upgrades then the systems would have counted as re-manufactured second hand equipment and you could have relied on the DOC covering that variant or the same DOC if it referred to a TCF covering all variants. In the UK implementation the regulation that excludes components is 7 (2) which states (2) For the purposes of these regulations, electrical apparatus:- (a) consists of a product with an intrinsic function intended for the end user; and (b) is supplied or intended for supply or taken into service or intended to be taken into service as a single commercial unit which is- (i) an electrical appliance (ii) an electronic appliance; or (iii) a system The 'single commercial unit' phrase would seem on the surface to exclude plug in units form the scope of the UK regulations and thus allow the upgrades by customer to be under the same conditions as is fitted by your service organisation. The UK Department of Trade and Industry intend to issue an updated version of their own guidelines in the next couple of months in response to the Commission guidelines and it will be interesting to see whether they fall in line with the Commission in this matter. Nick Rouse
EMC Standards
In asking whether the 4 year transition period apply to products already deemed compliant I presume our RCIC guest means product designs. The EMC directive does not have any grandfathering of old designs. The directive refers to individual items of equipment. That item must meet current requirements on the date that it is first supplied irrespective of whether it is the first of a new design or the latest item from a long standing production run. It may be sold second hand thereafter without having to meet newer requirements. However some of the harmonised standards have been issued with 'certification clauses' which do refer to new items made to old designs that were certified to previous standards or versions of standards and give a later date by which such items must comply with the new standard or version. The Commission has come down very firmly against any form of certification clause and insists that harmonised standards, like the directive must apply only to individual items and not refer to to previously produced items. This is the basis of the Commissions refusal to publish ammendment A12 to EN61000-3-2 in the OJ discussed at some length in another thread. In a recent agreement between CENELEC, who draw up the standards, and the Commission the so called 'Memorandum 6' was revised in a way which would abolish certification clauses and apply a uniform transition period of 4 years by setting the appropriate date of withdrawal of conflicting standards (dow). Strictly speaking this only applies to new versions of old standards and does not apply to new product or product family standards that take equipment out of the scope of the generics of to cases where, as in EN61000-3-2 the scope of the standard has been widened to take in equipment outside the scope of the old version. There was some expectation that this principal would apply more broadly but if EN55103-2 -3 are eventually published with a dow of 1 Mar 1997 and listed in the OJ obviously this is not so. Nick Rouse
Re: Radioactive Materials in TTE
Two relatively common uses of radioactive materials in electronics are tritium powered luminous bars 'Betalights' and some very fast gas discharge tube type surge arrestors. The common slower telephone grade ones have no radioactive materials. Nick Rouse
Re: Industrial Plugs and Sockets
I believe the reference is to the ICE 309 series of plugs and sockets. IEC 309 is equivalent to CEE 17 and is listed in the OJ with relevance to the low voltage directive Nick Rouse
Re: EMC/Plug-in radio cards
There is nothing in the EMC directive itself that recognizes ITE as a separate catorgory, this catorgory only appears in the harmonised standards. The directive is the basic document and it calls for all radiocommunications equipment (except amateur radio) to have EC type examination. Certainly the UK Radiocommunications Agency, and I suspect other national bodies, interpet this to include almost everything that emits electromagnetic energy anywhere within a very wide spectrum as an essential part of its function. Plug in radio cards that include a transmit function certainly fall within this definion. Nick Rouse
RE: EMC Standards
Drafts are being circulated at various stages of the process for: revisions to EN 50082-1, the residential, commercial and light industrial immunity standard; revisions to EN 50082-2, the industrial immunity standard, IEC 1326-1 EMC requirements for electrical equipment for measurement, control and laboratory use: general requirements, IEC 1326-10 particular requirement for equipment in close proximity or direct contact with an indusrtrial process, IEC 1326-20 particular requirements for equipment used in laboratories or test and measurement areas with a restricted electromagnetic environment. IEC 1326-30 particular requirements for portable test and measurement equipment that is powered by battery or from the measured circuit. (these latter 4 will become EN61326-1, -10, -20 -30 when adopted by CENELEC for European purposes) EN55105 Immunity requirements for telecomunications terminal equipment EN55106 (possibly to be named EN50024 Immunity requirements for information technology equipment (non-TTE) EN12016 EMC product family standard for lifts, escalators and passenger conveyors - emmissions awaiting listing in the OJ are EMC immuity standards for: EN510130 components for fire, intruder and social alarm systems , EN61131-2 Programmable controllers, Electrical requirements and tests (this includes EMC immunity) These and possibly other product or family specific EMC standards that I have missed as well as directives that have their own EMC requirements outside the EMC directive will call up various immunity tests from the IEC1000-4 series or its European equivalent. EN61000-4 series or ENV series pre-standard where draft or revisions are not ready. or judged not suitable. All the above are likely to published or listed some time this year or early next. Following the adoption of a revised Memorandum 6 by CENELEC a uniform 4 year transition will be applied in any updated standard. This does not apply explicitly to new product or family specific standards where these replace the generic standards for those products but it is understood that there is a good chance of this 4 year transition being applied in these cases If the drafts are confirmed the basic standards for immunity tests that that will be called up are:- EN50081-1:- ENV50140 (in lieu of EN61000-4-3) radiated RF ENV50141 (in lieu of EN61000-4-6) conducted RF EN50204 radiated RF from digital radio-telephones EN61000-4-2 electrostatic discharge EN61000-4-4 electrical fast transients EN61000-4-5 surges EN61000-4-8 power frequency magnetic fields EN61000-4-11 voltage dips and interruptions EN50082-2:- as EN50082-1 EN55105:- ENV50140 ENV50141 ENV50142 (in lieu of EN1000-4-5) EN61000-4-2 EN61000-4-4 EN61000-4-11 EN55106 (EN55024):- ENV50140 ENV50141 ENV50142 EN61000-4-2 EN61000-4-4 EN61000-4-8 EN61000-4-11 EN61326-1:- ENV50140 ENV50141 EN61000-4-2 EN61000-4-4 EN61000-4-5 EN61326-20:- as EN61326 -1(but different limits) EN61326-30 ENV50140 EN61000-4-2 Nick Rouse
Re: European Power cords
The UK measure that relates to power cords is the Plugs and Sockets (safety) Regulations 1994, Statutory Instrument 1994 No. 1768. I have not read this measure but I understand that it requires that mains powered electrical equipment being supplied in the UK and likely to be sold in the UK to domestic consumers must be supplied by the 'first supplier' i.e. manufacturer or importer, with a mains lead with a properly fitted plug. This plug must be either a UK style fused 250V 13A plug to BS 1363A with a correctly rated fuse or a plug to a type approved for use in a EEA member state in which case an approved conversion adaptor to BS1363A again fited with a correctly rated fuse must be supplied. This requirement came into force on 1 Feb 1994. It was not brought in under the Low Voltage Directive (implimented in the UK by Statutory Instrument 1994 No. 3260) but as secondary legislation under the Consummer Protection Act. Such national measures that may be thought to be in conflict with European directives must be submitted to the Commission under Directive 83/139/EEC, as amended, who may order a delay before implimentation to allow for any objection to be raised and dealt with. There were objections from the Commission and others to this measure but they were finally resolved and the measure approved by the Commission. I spoke to Nick Winter who is responsible for the unit at the UK Department of Trade and Industry (DTI) that deals with electrical safety legislation. He told me that in trying to steer the Plugs and Sockets Regulations through the 83/139/EEC mechanism his unit had done a survey of other EEA members states to look for requirements for national style plugs. They found nearly all had some such requirement. Most had, in implimenting the LVD, taken the requirement in Annex 1 1(c) of the directive that 'the electrical equipment, together with its component parts should be made in such a way as to ensure that it can be safely and properly assembled and connected' and implimented it for their state to require that mains connections be made with national style mains plugs and sockets. My conclusion is that it is fine for the distributor in the UK (who as importer becomes first supplier) to substitute UK power cords for US ones for units for sale in the UK. There is a good chance that it would be fine to substitute other other power chords for other destinations but you would have to examine the national laws in each state to be sure. All this demonstrates that Europe is very far from a single market. Vic Boersma says that 'the issue here is not UK Statutes, but EU Directives, which are legally binding laws of the European Union that become mandatory by their transposition into national laws of the Member States.' This misses the point that the directives are not in themselves legally binding on individuals or companies. Member states are treaty bound to 'approximate' national laws to the directives but these approximations, which are legally binding on indivduals in that state, are in many cases just that, approximate. Member states can, via the 83/139/EEC mechanism introduce national measures in derogation of the principal of the free movement of goods and several hundred such measures have been notified under this mechanism. The Commission can bring member states to court for incorrect implimentation of the directives and in one case an individual successfully challenged a member state's implimentation of a directive in the European Court but such litigation is not for the faint hearted. Vic was however much nearer the truth than me in one other matter. In a recent post he used the definition of rated voltage in IEC950 to deduce that the LVD did not apply to equipment that was powered by a voltage below the limit but generated voltages within the limits. I'm still not sure of using IEC950 but the conclusion he came to agreed with the interpretation of phrase 'designed for use with a voltage rating of ...' given by Nick Winter at the DTI. They regard the directive as applying only to equipment powered by voltages within the stated limits Nick Rouse
RE: AC Powerline harmonics
Richard Nute suggests there is a power limit to the effectiveness of a inductor in meeting the harmonic limits. If you are prepared to use multiple inductors and capacitors in a low pass filter configuration between the rectifier and the linear regulator there is no theoretical limit to how much you can suppress harmonics. The limit is the practicality of the use of such filters. You tend to need values of several henries capable of taking the DC current which may be 10's of amps without saturating. Such inductors are large. Nick Rouse
Re: AC powerline harmonics
No, the current into a so-called linear power supply is anything but sinusoidal. It consists of sharp current peaks whenever the voltage waveform exceeds the voltage on the resevoir capacitor by more than the rectifier diode drops. The more you try to increase the efficiency by reducing the transformer winding resistance, decreasing the rectifier diode drops, increasing the size of the resevoir capacitor and decreasing its effective series resistance, the shorter and sharper the current peaks. It is precisely this type of current waveform that lands the equipment in Class D of EN61000-3-2. A point in that standard that some may not have noticed is a that there is a complete ban on the use of half wave rectification. Nick Rouse
Re: EN61000-3-2 applicability ?
Until reading John Cross's reply I had interpreted section 7 'The following limits apply, with the provision that the limits for high power equipment (greater than 1kW) for professional use are kept under consideration' to mean that the limits did apply to such equipment but the commitee was thinking of changing the limits at some time in the future. If John's interpretation is the correct one perhaps he could tell us the reasoning behind this. Professional equipment will cause just as much trouble to other users if it distorts the mains waveform as would domestic equipment and being in general more expensive could more easily bear the extra cost of meeting the limits. It seems a somewhat illogical exclusion (not that this ever limited European regulations). I would also be interested to know if John has any further inside information on the reported refusal of Mr.Kiriakadis to list amendment A12 in the OJ. Nick Rouse
Re: Routine Hipot testing )
Amendment 2 of EN61010-1, the European version of IEC1010-1 has not yet been listed in the Official Journal. Therefore the change that makes appendix K normative and 100% production hipot testing a requirement of that standard is not yet mandatory on those for whom EN61010-1 is applicable and who choose compliance with the harmonised standards to meet the requirements of the LVD. This situation is however likely to short lived as a listing on standards under the LVD is due soon and as the date of withdrawal of conflicting standards to the amendment passed on 1 Apr 96 the requirement will come into force immediately on listing in the OJ Nick Rouse
Re: Who can apply the CE Ma
Bob Newall asks if you must have an approved quality system to self declare compliance. I take it by this he means without a certificate from an approved body for that directive, since declarations of conformity are always made by the manufacturer or his authorised representitive. The answer is that with some directives this is required but for the LVD, EMC and Machinery directives, if type examinationl is not require, a manufacturer can declare compliance based on his own or any others measurements without any quality system being mandatory. Nick Rouse
Re: Who can apply the CE Mark?
Your customer seems to want to gain all the kudos of being the manufacturer without incuring any of the liabilities that this involves. There are limits to which this can be done I can give some guidance on UK law in this respect and I suspect other EU countries will have similar requirements. It is a requirement of the Electrical Equipment (Safety) Regulations 1994 (SI 1994 No. 3260) that equipment must be marked with the manufacturer's brand name or trade mark where possible and on the packaging where not (Schedule 3. 1(b)) Thus if your customer is going to put their brand and not yours on the equipment, they are declaring themselves to be the manufacturers of the equipment and must bear the liability that that entails. CE marking must be applied and the declaration issued by the manufacturer or his authorised representitive establised in the commuity in respect of the EMC directive (SI 1992 No.2373 regulation 30(c) and 30(d) and from next year for the Low Voltage Directive (SI 1994 No. 3260 regulation 9 and 10. This declaration must have the name and address of the manufacturer and the identity of the person signing the declaration as, or on behalf, of the manufacturer or their authorised representitive in the community. This declaration must be keep in the community at the disposal of the authorities. The manufacturer as a body corporate and the signatory personally are liable for the validity of the declaration. They can use third party information (e.g yours) as the basis for this declaration but the must take all reasonable steps to ensure this is valid. They cannot just pass on your assurance, unchecked and evade responsibility. Nick Rouse
Re: Standards Route vs. Essential Requirements Route
There is no either/or choice between the essential requirements and the harmonised standards. You must always meet the essential requirements. If it is found that your equipment fails to meet the essential requirements despite meeting the harmonised standards the equipment will still be in breach of the directive and sale of it may be prohibited. It will however be presumed to meet the essential requirements until this is shown. This means that the authorities cannot demand any futher proof of compliance with the directive before you are allowed to market it unless they have good reason to believe it fails the essential requirements. If your product does meet the harmonised standards and you had no good reason to believe that, despite this, it failed the essential requirements you would stand an excelient chance of sucessfully pleading due diligence but this would not stop the equipment being banned until rectified. The other possible routes, beside harmonised standards, to showing compliance with the essential requirements vary with the directive and the type of equipment. In the EMC directive, for equipment other than radiocommunication transmitters you may use any other suitable means provided this is given in a technical constuction file and approved by a competent body. For radiocommunication transmitters type examination will require compliance to harmonised standards, usually certified by an accredited test house. The LVD will allow you to use any other means to show compliance to the essential requirements but from next year you must have a detailed justification ready in advance. To your specific questions, 1. Yes you do have to meet all normative references if they apply. 1.a Yes even if they are not themselves listed in the OJ 2.If you have your compliance to the harmonised standards certified by some approved body, either because you have to or you choose to, they will tell you of the relevant standards, but in choosing they will rely on your information as to the application of your equipment if this is not obvious. You bear responsibility for the correct standards being applied but again if you rely on a body approved for that pupose by the direcive and have given them accurate information you should be able to plead due diligence. If you are allowed to, and choose to test to the standards yourself you will have to search the standards youself and decide which is applicable. 3. Most harmonised standards have date of withdrawal of conflicting standards that is several years after the date of publication. This allows the older standards to be applied until the date of withdrawal in those cases where there was an older standard or in those cases where they have been called indirectly by an undated reference. If they are called indirectly by a dated reference the new standard does not apply until the reference is updated. The revised Memorandum 6 from CENELEC calls for a 4 year transition period for new standards but leaves unclear some matters where the scope of a standard changes. 4.Non-question, see above Nick Rouse
Re: Dates on MDoC
The requirement for the last two digits of the year in which the CE marking was affixed on the DoC is the 6th indent of Article13 (6)B of the CE marking directive 93/68/EEC. Note that year numbers are not called up for the marking itself. Nick Rouse
Re: FCC 47 CFR Indust Equip
Jon Curtis is right about the FCC regulations in saying that emission measurements made for European compliance will in general sufice for FCC regulations, especially if you are in one of the classes for which fully compliant measurements are not mandatory and you are reponding to the statment in 15.103 'Although not mandatory, it is strongly recommended that the manufacturer of an exempt device endeavor to have the device meet the specific technical standards of this part'. This is however one difference between the European and American emission standards that was once only rarely of concern but becoming of increasing importance. This is the FCC requirement to extend the range of measurents to 2GHz if the highest clock frequency is over 108MHz. The European tests are limited to 1GHz. Intel have stated that they expect that by the end of the year their bottom end processor will be a 120MHz Pentium. Soon we can expect this difference to apply to most PC based products. Nick Rouse
Re: ESD testing on exposed connector pins
Ron Wellman suggests that it is a truth universally acknowledged that ESD applied to a connector pin will almost always lead to failure. Without precautions this may be so but for low frequency connections it is possible to protect not only against permanent damage but also against loss of data as required by the EMC tests under the EMC directive. A combination of filtering and clamping very close to the connector can provide the required protection. The closeness to the connector is however vital. The threat from the discharge comes not only from its amplitude but from its very fast rise time (0.7ns). At this speed a path to ground within the equipment of only a couple of inches presents an appreciable impedance and will constitute a radiating antenna broadcasting to the rest of the equipment. Filters built in to the connector with feed through capacitors are best but they should not spread the energy out over such a long period that it is sensed as a valid signal. If you are fighting to keep the bandwith up while providing protection the best scheme is to use a modest filter in the connector to slow the edge of the waveform, closely followed by clamping diodes and then a further filter to reduce the clamp level to below the signal threshold. This can be expensive and bulky if you have a lot of signals but it can be done. Nick Rouse
Re: UK EMC law efective date
prosecutions being brought but I have direct evidence of one product being withdrawn from the market as a result of action by a Trading Standards Officer. I hope this rather lengthy reply finally kills this rumour Nick Rouse
Re: ESD testing on exposed connectors
The rationale offered by Tom Cokenias is fine for equipment that is always configured with cables on all connectors. The pins would then would not come within the criteria that I suggested of the user being reasonably expected to touch them. However many items of equipment are designed with connectors for optional attachments. A PC manufacturer does not expect that every computer sold will used only with a device on every serial and parallel port. The test is intended to simulate a real risk. Where to apply the test should surely be governed by where this risk is real. Nick Rouse
Re: ESD testing on exposed connectors
I don't know of any official standard that gives a specific ruling on connector pins. The generic immunity standards refer without comment to the basic standards and the basic standards refer to points accessible to personnel during normal use including customer's maintenance. The overview of immunity tests, standard IEC1000-4-1 reiterates this saying that the ESD shall be applied to all normally accessible points on the EUT The opinion of the Competant body that we use is that if the user can reasonably reach a connector and may do so at some time during any operation that you might reasonably expect him or her to do, the pins of the connector should be tested if there is a fair chance that a finger or metal object approaching the connector would discharge to the contacts rather than the shell. Thus large flat connectors with non-recessed contacts or plastic shelled connectors should have the pins tested but narrow metal shelled connectors with the shell earthed and contacts recessed need only be tested to the shell. A few tests have shown that female BNC's discharge to the shell but male BNC's can discharge to the pin. Standard width D types with female contacts discharge to the shell and those with male contacts nearly always do. Wide shell 3 row D types can discharge to the pins with both sexes. Do not forget the indirect ESD test. I have found that for plastic cased equipment with unscreened wires running away from the connector internally an ESD test to a coupling plane 100mm from a connector face can have more effect than a direct discharge to the pin. Nick Rouse
Re: Laser Safety in EN61010-1
EN61010-1 was listed as a harmonised standard under the LVD in November 1993 (OJ 93/C319/02). IEC825 is cited directly in section 2.1 of EN61010-1 as a normative reference but would in any event be invoked by by section 14.1 that states that where safety is involved components shall comply with applicable safety requirements in relevant IEC standards. Ammendment 2 to EN61010-1 (although this is not yet listed ) expands further on this use of IEC standards and gives a little flow chart on their application. Having said all this it should be borne in mind that compliance to harmonised standards is not absolutely mandatory for compliance with the LVD. The catch is that if you do not fully conform, then from next year you will need detailed documentation in advance of marketing showing how you achieve equivalent safety to that given by the harmonised standards. Nick Rouse
Re: Low Voltage Directive
The scope of the low Low Voltage Directive is equipment designed for use with a voltge rating between 50 and 1000V ac and between 75 and 1500V dc. Anythiing that is neither powered not generates voltages in that range is clearly outside the scope of the directive. There is a second ammendment A2 to IEC 1010-1 It was published in June 1995. It has not however yet been listed in the OJ under the LVD although I expect it will be very soon. The last listing was in July 1994 and there are a number of standards awaiting listing. The two amendments to IEC950 (1992) were listed in November 1993. Peter Perkins mentions the General Product Safety Directive 92/59/EEC. This is the most vaguely worded of directives, it has no CE marking requirements, no declaration of conformity requirements, no scheme of listing harmonised standards under it, no scheme of notified or competent bodies under it and no specified means of demonstating conformity. The directive only applies to products not covered by other community law (and a standard is not a law) . In the absence of that, the next level of priority is National Laws. In the absence of these the conformity of the product shall be assessed having regard to voluntary national standards giving effect to a European standard. It does not specifically say you have to meet the standard and there is a get out clause that says that the feasibility of obtaining higher levels of safety or the availability of other products presenting a lesser degree of risk shall not constitute grounds for considering a product to be 'unsafe' or 'dangerous'. Having said that it may be prudent to know that your product does not contravene standards such as EN60950 or EN61010-1 which do include provisions that apply to voltages below the levels of the LVD and non-electrical hazards but there is no need to have them formally tested nor to have formal documentation to show compliance. Moreover I think you would be justified ammending these standards if you felt happy that the product was safe. I do not think you should mention the general product safety directive on the declaration of conformity which is a formally defined document relating to those directives that require it. Like superfluous CE marks I think that superfluous delcarations of conformity should be discouraged. Nick Rouse
Re: Product Liability Directive
The Product Liability Directive is 85/374/EEC. It was published in the Official Journal ref: OJ L210 of 7-Aug-1985 and came into force on 30-Jul-1988 It was and carried into UK Law as The Consumer Protection Act 1987 which came into force 1-Mar-1988 Related is the General Product Safety Directive 92/59/EEC published in the Official Jounal ref: OJ L228 of 11-Aug-1992 and came into force on 29-Jun-1994 and was carried into UK Law by The General Product Safety Regulations 1994 Statutory Instrument 1994 No.2328 which came into force 3-Oct-1994 Nick Rouse
Harmonics Standards
At the risk of repeating the information in earlier posts and stating facts well known to many here I will try and summerise the confused position over harmonic current limits as I understand them. IEC555-2 and IEC1000-3-2 are both international standards and are therefore not directly legally binding anywhere. When these standards are adopted by the European standards body CENELEC they are given a EN number and are given a foreword which gives a date of announcement (doa), that is the date CENELEC releases the text; a date of publication (dop), that is the latest date by which the member states of the EU must publish native language versions and adopt them as national standards; and a date of withdrawal of conflicting national standards (dow) Publication by CENELEC or of the national standards verions does not of itself make the standards binding in Europe. This only happens when the title of the standard itself has been listed in the Official Journal of the European Communities (OJ) or they have been called up by some other standard, the title of which has been published in the OJ and in addition the dop date has been reached. At this date equipment not within the scope of a conflicting national standard must comply if it is to be CE makred for EMC. IEC555-2 was publised by the IEC in 1986 adopted by CENELEC as EN60555-2 in 1986 and listed in the OJ in Feburary 1992 (Ref: OJ C44 19/02/92) The scope of this standard was household appliances and similar electrical equipment. IEC1000-3-2 was finally published by IEC in 1995 but had by this time already been adopted by CENELEC as IEC61000-3-2 with a doa of 15 Sep 1994, a dop of 1 Jul 1995 and a dow of 1 Jan 1997 A grandfather clause allows existing designs designs within the scope of the earlier standard and conforming to that standard to continue in production until 1-Jan-2001 The scope of this standard includes all electrical equipment that connects to the low voltage public power supply with a rating less than 16 amps per phase with lower power limit exemptions in some classes. The lower limit on class D equipment was to be lowered from 75W to 50W four years after coming into force although it is not clear exactly what this means. The limits in the newer standard are stricter than the earlier one and this lead to strong protests and it was commonly believed that it had been agreed to delay the dates of this standard beforeit was listed in the OJ as was done with IEC1000-3-3. However for some reason this was not done and the listing in the OJ made in Sep 1995 (Ref OJ C241 16/09/95) refers to the standard as published by CENELEC. Since the dop had passed the standard became immediately an absolute requirement if a CE making was to be applied for all equipment that was not within the scope of EN60555-2 but was now within the scope of EN1000-3-2 since there were no conflicting standards to withdraw. CE marking is not mandatory for the EMC directive until 1-Jan-1996 but in places like Germany where the alterative up to that dateis to comply with the in some ways stricter VDE standards, this presented an immediate problem for manufacturers. In the absence of any future changes, equipment within the scope of EN60555-2 may continue to meet only this standard until it is withdrawn as conflicting with EN61000-3-2 on 1-Jan-1997. It has been proposed that EN61000-3-2 be ammended so that the dow is delayed until 1-Jan-1998 allowing EN60555-2 to continue to apply to equipment within its scope until that date. It was farther proposed that a clause should be added to allow equipment within the scope of EN61000-3-2 but not EN60555-2 until 1-Jun-1998 to comply. It is not proposed to change the date of the lowering of the lower power limit of class D equipment immediately but this may be changed in the intervening time. This proposal is out for a 2 month vote. I rang around several people today that might be in a position to know the result of this vote but none did. Even if the vote is successful, and it is not certain, it is unlikely to be listed in the OJ until May. This leaves the crazy situation of having to conform for 6 months or so and then having 18 months in which you don't need to. I suspect the UK authorities will turn a blind eye to to a technical breach of this standard during this time provided the vote is positive but I not so sure the German authorities will. Nick Rouse
Re: Declaration of Conformity
There is no need to put the DoC in the instruction manual or indeed issue a copy with every product. The minimum required is that one copy be kept in Europe, available to the authorities on request for 10 years after the last sale, at your company office, your approved representitive of failing that the person who first supplies the product in Europe. If you are going to use the technical construction file route the DoC will need to identify that file, give the name and address of the competent body which issued the report or technical certificate on that file and the date and number of that report or certificate. It should also state which if any EMC standards the product conforms to, the name and address of the manufacturer and, if different, the name and address of the person accepting liability for conformance and signing the DoC. Although not required a copy shipped with every item may avoid administative delays if the authorities were to question compliance. Nick Rouse
Re: Need info of immunity test lab in UK
For telecommunications equipment you need not just EMC test reports from a test house but Type Approval from: RadioCommunications Agency Room 514 Waterloo Bridge Road London SE1 8UA Tel +44 171 215 2129 you need forms RA227, RA249 and guides RA200 RA207 Test houses recognised as competent for this work include ERA Technology Ltd. Cleeve Rd. Leatherhead Surrey KY22 7SA Tel +44 1372 367000 Fax +44 1372 377927 Assessment Services Ltd. Segensworth Road Titchfield Fareham Hants. PO15 5RH Tel +44 1329 443300 Fax unknown TRL EMC Ltd. Long Green Forthampton Gloucester GL19 4QH Tel +44 1684 833818 Fax +44 1684 833858 Radio Frequency Investigation Ltd. Ewhurst Park Ramsdell Basingstoke Hants RG26 5RQ Tel +44 1256 851193 Fax unknown KTL Ltd. Newlands Science Park Inglemire Lane Hull HU6 7TQ Tel +44 1482 801801 Fax +44 1482 801806 I can probably dig out a few more if you need them Nick Rouse
