RE: Regulatory Compliance stifles innovation?

[emc-p...@ieee.org]

Hi Oscar:


> While I agree with you regarding Product Safety engineers in
> the field today, there is a group of System Safety engineers
> that have always (since 1962 when the concept began) taken
> the risk assessment and mitigation approach.

I did not mean to suggest or imply that product safety 
engineers must learn and use risk assessment and mitigation.  

If the objective is to prevent injury, then we must first
identify (in a product) the potential "causes" for injury. 
If a product employs voltages greater than, say, 30 volts,
then the product has a potential to cause an electric shock
type injury.  This is NOT a risk assessment.  

Risk assessment is very difficult to define.  Wikipedia is
about the only source with a reasonably complete definition.
(My System Safety handbook doesn't define risk assessment.)  
The Wikipedia defines risk assessment in terms of magnitude 
of the loss and the probability that the loss will occur.  
These are NOT criteria for prevention of injury.  Rather,
risk assessment assumes an injury will occur and addresses
the means to reduce the probability of occurrence.

The re-invention of safety engineering requires the 
engineer to identify the potential "causes" for injury
that exist in a product.  Today, we just don't think this
way.


Best regards,
Rich


ps:  I do agree that product safety engineers and system
 safety engineers could indeed reduce the re-invention
 of the wheel! 

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RE: 4 wire resistance measurement lead set

[emc-p...@ieee.org]

 


  _  

From: Ken Javor [mailto:ken.ja...@emccompliance.com] 
Sent: Thursday, November 30, 2006 2:31 PM
To: emc-p...@ieee.org
Subject: Re: 4 wire resistance measurement lead set


The old HP 4328A (I think there is a 4328B modern digital version) used a 1
kHz ac waveform and averaged the readings to zero out any galvanic potentials.
 Also it used very small potentials and currents so that it would not "punch
through" any dielectric build-up or corrosion within the bond being measured. 
The latter property is important if you are measuring the surface conduction
properties of a complex material.  For EMI, as opposed to lightning or safety
ground measurements, I think it was the best milliohmmeter ever made.
 

Also consider the Keithley 580 Digital Microohmmeter. It has low-power
dissipation in the unknown, selective DC or 1 kHz test current, 2-wire or
Kelvin 4-wire, has a range of 2000 Ohms to 10 microohms and yields very stable
readings. It's available used, and is the best microohmmeter ever made.
 
(No conflict Ken; notice I said "micro". )
 
Ed Price
  ed.pr...@cubic.com
NARTE Certified EMC Engineer & Technician
Electromagnetic Compatibility Lab
Cubic Defense Applications
San Diego, CA  USA
858-505-2780 (Voice)
858-505-1583 (FAX)
Military & Avionics EMC Is Our Specialty

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Re: Regulatory Compliance stifles innovation?

[emc-p...@ieee.org]

Rich,
 
It's the contrary one again...
 
The standard you are quoting as problematic is IEC 60950-1.  Going back into
history, this standard was a derivation of IEC 950 which itself was created by
combining two existing standards, IEC 380 and IEC 435.
 
IEC 435 was derived from UL 478 and took an approach which I shall paraphrase
as "you never know what may go wrong, so don't spend too much time looking at
fault conditions, just ensure that the enclosed parts aren't too flammable
and, to be on the safe side, make sure the enclosure can reasonably contain
any fire that may nevertheless start".  Of course this is something of an
oversimplification, but I think it adequate for this discussion.  IEC 435
covered electronic data processing equipment which in those days meant rooms
crammed full of large machines containing lots of printed circuit boards.
 
I always seemed to me that IEC 380 was a derivation of VDE 0730 inc. Part 2P,
though I never checked this and it's now probably too late.  Anyway, it took
the approach that you should perform enough fault tests to ensure that fire
could not start in the first place.  It consequently had much less stringent
flammability requirements than IEC 435.  IEC 380 covered office machines, such
as photocopiers. 
 
This dualistic approach was incorporated into IEC 950 and was maintained in
IEC 60950.  I agree that IEC 60950-1 has become biased towards the
preselection of plastic parts and  don't have the standard to hand right now
to quote the clause number, but if you look hard you should find it.
 
Regards,
 
Richard Hughes
 
 

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Re: Regulatory Compliance stifles innovation?

[emc-p...@ieee.org]

Hi Rich,
 
Well, you know me, I'm not so easy to convince!
 
Safety standards (well, at least IEC 60950-1) have various constructional
requirements to ensure that not only is the connection good when it leaves the
factory gate, but it has a good chance of staying that way throughout the life
of the product.  I do not recall any such requirement in CISPR 22 or the like.
 
Take earthing as an example, since it is important for both safety and EMC...
 
IEC 60950-1 has a requirement that when you screw through an insulating
material which could shrink in use (such as a pcb substrate) then you need to
use a resilient washer to maintain contact pressure if the contact is relied
on for protective earthing.  Perhaps this is more particular to safety because
the fault currents can be very high, but if one or more EMC contacts are not
made then the emissions are likely to increase and the immunity decrease.
 
IEC 60950-1 has requirements to limit the electropotential when using
dissimilar metals.  This reduces the likelihood of corrosion occurring during
the life of the product.
 
IEC 60950-1 has various requirements regarding the type of screw and
associated construction (e.g. number of engaged turns) that can be used for
providing a protective earth connection.  This ensures the resulting
mechanical joint has a certain degree of robustness.
 
Of course these constructions are in the standard because they have been found
to work over the years.  You could presumably replace the resilient washer
requirement with some sort of thermal cycling and ageing test; perhaps the
electropotential requirement could be replaced by a salt spray test; and the
other constructional requirements replaced by a combination of
thermal-humidity cycling and vibration test.  In this way you would have
replaced requirements that are easy and cheap to incorporate and inspect to by
expensive and lengthy tests.  But if you do not incorporate the performance
tests then you have just diminished safety in the longer term, even if the
unit happens to pass the earth bond test during type examination.
 
Regards,
 
Richard Hughes
 
 

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RE: GR-1089 Issue 4 and Surge on Ethernet

[emc-p...@ieee.org]

Jim,

Thank you for the clarification.  

You answered my question when you stated, "For example interfaces with 
65,
140, 200 or 270V sidactors / thyristors or Semtech LC-03 devices that are
grounded that are on the surged side of the transformer need to be tested per
4.6.9.1.1".  This section does not clearly distinguish between surge
protectors that are grounded or ungrounded and that was the nature of my
question.  From your response, this section only applies to secondary
protectors that are *grounded*.

Thx,


Joe

~~
Joe Finlayson
Tel:   (508) 357-8273
Fax:  (508) 357-8289
Email: joefinlay...@motorola.com

Motorola, Inc.
Embedded Communications Computing
46 Lizotte Drive
Marlborough, MA 01752
USA
~~


From: JIM WIESE [mailto:jim.wi...@adtran.com] 
Sent: Thursday, November 30, 2006 5:35 PM
To: Finlayson Joe-G3162C; Gelfand, David; emc-p...@ieee.org
Subject: RE: GR-1089 Issue 4 and Surge on Ethernet

Joe,

The reason we (GR-1089 TTF) added the caveat regarding secondary protection to
ground had to do with the possibility of longitudinal to metallic conversions
as a result of asymmetric firing that would be synonymous with the firing of a
primary protector.  Protectors on the chip side of an isolation transformer
will not do this conversion, thus performing a metallic surge on an Ethernet
port would result in current flow paths that would not exist in the real world.

In the real world if a transient is induced into the cable, the voltage would
be the same on all conductors and there would be no current flow through the
windings of the Ethernet isolation transformer regardless of what paths to
ground exist on the chip side.

So basically the exemption was a practical way to eliminate a test that added
no value.  It also reduces cost to the industry by eliminating the need for an
expensive and un-necessary component to protect an 10/100 baseT Ethernet port.
 There were also concerns with GigE interfaces and the ability to protect them
>from metallic surges with commercially available devices and still meet
performance criteria.  So we felt the exemption was a positive and reasonable
way of addressing the issue.

As far as 4.6.9.1.1, I received the exact same question from a test lab
yesterday.  Here is essentially the same text I sent the lab.

Dear XYZ LAB,

The two conditions you mention below only apply to Ethernet interfaces with
regard to metallic surges.  Longitudinal surges on Ethernet ports always
apply, unless exempted by one of the 3 bullets at the beginning of 4.6.9.  As
far as protection to ground, components on the IC side of the transformer that
connect to ground do not cause the metallic exemption to be lost as the
transformer provides isolation from a longitudinal to metallic conversion.  If
the TVS components that are grounded are on the surged side of the
transformer, the metallic surges are not exempt. 

 4.6.9.1.1 applies to all products with any kind of secondary voltage
protection.  However, as with the rest of section 4, the intent of secondary
protection relates to those components on the exposed side of an isolation
transformer, not the chip side.  For example interfaces with 65, 140, 200 or
270V sidactors/thyristors or Semtech LC-03 devices that are grounded that are
on the surged side of the transformer need to be tested per 4.6.9.1.1. 
Generally protection on the IC side is about 5V and even with ADSLx is usually
less than 20V and they are clamping devices.  As a result there isn't really
much if any value in trying to remove these and doing a surge on the exposed
side at 5-20V, the energy is simply too low and is a waste of time.  The IC's
get as much or more energy from the full surge.

Hopefully this answers your question.  


Jim
 
Jim Wiese
NEBS Project Manager/Senior Compliance Engineer
ADTRAN, Inc.
901 Explorer Blvd.
Huntsville, AL 35806
256-963-8431
256-714-5882 (cell)
256-963-6218 (fax)
jim.wi...@adtran.com
 


From: Finlayson Joe-G3162C [mailto:joefinlay...@motorola.com] 
Sent: Thursday, November 30, 2006 2:16 PM
To: JIM WIESE; Gelfand, David; emc-p...@ieee.org
Subject: RE: GR-1089 Issue 4 and Surge on Ethernet

Jim,

I am not sure I understand your explanation of the location of the surge
protection device with respect to the primary or secondary side of the
transformer.  The way I look at this requirement, the key is to *not* provide
a path, direct or through a protection device, back to Ground (C.O. Ground,
Shelf Ground, Frame Ground, Earth Ground, etc.).  If there is surge protection
on either side of the transformer and it is either not referenced to Ground at
all or referenced to Logic Ground only, the exemption can be taken.  While
referencing Logic Ground on the line (surge) side of the transformer or Shelf
Ground on the PHY side of the transformer makes no practical sense, it can
still be done.  Therefore, physical location of the surge protection device
may not necessar

RE: GR-1089 Issue 4 and Surge on Ethernet

[emc-p...@ieee.org]

Joe,

The reason we (GR-1089 TTF) added the caveat regarding secondary protection to
ground had to do with the possibility of longitudinal to metallic conversions
as a result of asymmetric firing that would be synonymous with the firing of a
primary protector.  Protectors on the chip side of an isolation transformer
will not do this conversion, thus performing a metallic surge on an Ethernet
port would result in current flow paths that would not exist in the real world.

In the real world if a transient is induced into the cable, the voltage would
be the same on all conductors and there would be no current flow through the
windings of the Ethernet isolation transformer regardless of what paths to
ground exist on the chip side.

So basically the exemption was a practical way to eliminate a test that added
no value.  It also reduces cost to the industry by eliminating the need for an
expensive and un-necessary component to protect an 10/100 baseT Ethernet port.
 There were also concerns with GigE interfaces and the ability to protect them
>from metallic surges with commercially available devices and still meet
performance criteria.  So we felt the exemption was a positive and reasonable
way of addressing the issue.

As far as 4.6.9.1.1, I received the exact same question from a test lab
yesterday.  Here is essentially the same text I sent the lab.

Dear XYZ LAB,

The two conditions you mention below only apply to Ethernet interfaces with
regard to metallic surges.  Longitudinal surges on Ethernet ports always
apply, unless exempted by one of the 3 bullets at the beginning of 4.6.9.  As
far as protection to ground, components on the IC side of the transformer that
connect to ground do not cause the metallic exemption to be lost as the
transformer provides isolation from a longitudinal to metallic conversion.  If
the TVS components that are grounded are on the surged side of the
transformer, the metallic surges are not exempt. 

 4.6.9.1.1 applies to all products with any kind of secondary voltage
protection.  However, as with the rest of section 4, the intent of secondary
protection relates to those components on the exposed side of an isolation
transformer, not the chip side.  For example interfaces with 65, 140, 200 or
270V sidactors/thyristors or Semtech LC-03 devices that are grounded that are
on the surged side of the transformer need to be tested per 4.6.9.1.1. 
Generally protection on the IC side is about 5V and even with ADSLx is usually
less than 20V and they are clamping devices.  As a result there isn't really
much if any value in trying to remove these and doing a surge on the exposed
side at 5-20V, the energy is simply too low and is a waste of time.  The IC's
get as much or more energy from the full surge.

Hopefully this answers your question.  


Jim
 
Jim Wiese
NEBS Project Manager/Senior Compliance Engineer
ADTRAN, Inc.
901 Explorer Blvd.
Huntsville, AL 35806
256-963-8431
256-714-5882 (cell)
256-963-6218 (fax)
jim.wi...@adtran.com
 


From: Finlayson Joe-G3162C [mailto:joefinlay...@motorola.com] 
Sent: Thursday, November 30, 2006 2:16 PM
To: JIM WIESE; Gelfand, David; emc-p...@ieee.org
Subject: RE: GR-1089 Issue 4 and Surge on Ethernet

Jim,

I am not sure I understand your explanation of the location of the surge
protection device with respect to the primary or secondary side of the
transformer.  The way I look at this requirement, the key is to *not* provide
a path, direct or through a protection device, back to Ground (C.O. Ground,
Shelf Ground, Frame Ground, Earth Ground, etc.).  If there is surge protection
on either side of the transformer and it is either not referenced to Ground at
all or referenced to Logic Ground only, the exemption can be taken.  While
referencing Logic Ground on the line (surge) side of the transformer or Shelf
Ground on the PHY side of the transformer makes no practical sense, it can
still be done.  Therefore, physical location of the surge protection device
may not necessarily dictate the ability to take this exemption.

Would you agree with that?

Also, can you please clarify on the intent of Section 4.6.9.1.1?  
Referencing
Section 4.6.9.1.1, Equipment Ports With Secondary Protection, was the intent
to label this section, "Equipment Ports With Secondary Protection Not
Referenced to Ground" and only apply that to the longitudinal surges if the
following conditions are met?

1.) The port does not have any secondary voltage-limiting protection 
to ground
2.) The unused pins of the port are not grounded solidly.

...or does this section apply to the metallic surges as well?

Thx,


Joe

~~
Joe Finlayson
Tel:   (508) 357-8273
Fax:  (508) 357-8289
Email: joefinlay...@motorola.com

Motorola, Inc.
Embedded Communications Computing
46 Lizotte Drive
Marlborough, MA 01752
USA
~~


From: JIM WIESE [mailto:jim.wi...@adtran.com] 
Sent: Wednesday, November 29, 2006 3:16 PM
To

Re: 4 wire resistance measurement lead set

[emc-p...@ieee.org]

The old HP 4328A (I think there is a 4328B modern digital version) used a 1
kHz ac waveform and averaged the readings to zero out any galvanic potentials.
 Also it used very small potentials and currents so that it would not "punch
through" any dielectric build-up or corrosion within the bond being measured. 
The latter property is important if you are measuring the surface conduction
properties of a complex material.  For EMI, as opposed to lightning or safety
ground measurements, I think it was the best milliohmmeter ever made.



From: "Garnier, David S (GE Healthcare)" 
List-Post: emc-pstc@listserv.ieee.org
Date: Thu, 30 Nov 2006 15:11:06 -0500
To: 
Subject: 4 wire resistance measurement lead set




Hello,

Problem: Would like to evaluate surface conductivity of different types of
metals...

1)  Can anyone suggest a "commercial 4 wire lead set" for conducting these
measurements?  

2)  Or, commercially available "product or test fixture" for measuring surface
conductivity of 
different metals or coatings there of?

3)  How does one measure Galvanic action between two dissimilar metals?

Thank you for your time.

Regards,

Dave Garnier



David Garnier 
e GE Health Care 
___ 


   David S. Garnier 
   Senior Technician 
   Functional & CT Engineering 
   3000 N. Grandview Ave - M/S W-1250 
   Waukesha, Wi. 53188 
   Tel: 262.312.7246 
   Cel:  414.899.7580 


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RE: was EN61326 -> standards' effective date interp

[emc-p...@ieee.org]

On Thu, 30 Nov 2006 06:54:46 -0800,
  "Brian O'Connell"  wrote:

> Ok, so what is the correct interpretation of requirements when the DoP
> and/or DoW for a standard, as published on Cenelec.org, do not agree with
> what is published on the EU site; i.e., the OJ 
> 
> Still confused after all of these years...

For directives such as EMCD, LVD, etc., we must see ``Date of cessation
of presumption of conformity of the superseded standard'' as published
in the OJ for the directive.

If you are not sure, maybe you can find the explanation in CENELEC Guide 25.

Regards,
Tom


Tomonori Sato  
URL: http://homepage3.nifty.com/tsato/

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RE: Regulatory Compliance stifles innovation?

[emc-p...@ieee.org]

Rich,

You wrote"

"Today, safety engineers don't think this way.  So, an
end-result safety standard would require a huge amount of
re-invention of the safety engineer job!"

While I agree with you regarding Product Safety engineers in the field
today, there is a group of System Safety engineers that have always (since
1962 when the concept began) taken the risk assessment and mitigation
approach. Most of these operate in government systems or industries that
are regulated (transportation, nuclear, etc.)

It would serve the Product Safety community well to interface with the
System Safety community so that there would be less reinvention of the
wheel.

One web link that might help is the International System Safety Society:
http://www.system-safety.org/

The size and complexity of the systems may differ but the concepts are the
same.


Oscar Overton
Product Safety
Lexmark International, Inc.

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  "Richard Nute"  

  ,   
  >cc:

  Sent by: Subject:  RE: Regulatory
Compliance stifles innovation? 
  emc-p...@ieee.org   

  

  

  11/30/2006 01:28

  PM  

  Please respond to   

  richn   

  

  




Hi John:


> Unfortunately it is difficult for a Safety standard to keep
> up with new technology and the fairly broad wording makes it
> open for many different interpretations...

If a safety standard was written as is an EMC standard,
we would not have these problems.

An EMC standard specifies the end-result, namely emissions
not exceeding a certain value.  The standard does not specify
what needs to be done to the equipment to achieve the end-
result, although the EMC report does include a description
of the various emission control mechanisms.

Today's safety standards do not specify the end-result.
Instead, the standards specify various constructions deemed
to make the product safe -- without saying how such
construction makes the product safe.  The safety report
describes the constructions, but does not describe how the
constructions make the product safe.  Consequently, such
safety standards cannot keep up with new technology.

What if a safety standard specified the end-result, namely
that injury shall be prevented?

This is not as difficult as it may seem.  For example, to
prevent electric shock injury, the end-result would be
that accessible parts shall not exceed a certain value (30
volts, for example).

In keeping with current requirements, this end-result
would apply under both normal operating conditions and
single fault conditions.  As with EMC, the standard would
not need to describe what needs to be done to the equipment
to achieve the end-result.

As with EMC, the report would describe the constructions
that prevent accessible parts from exceeding the limit,
both for normal operating conditions and single fault
conditions.

Today, safety engineers don't think this way.  So, an
end-result safety standard would require a huge amount of
re-invention of the safety engineer job!


Best regards,
Rich



Richard Nute
Product Safety Consultant
San Diego

Tel/FAX:  +1-858-592-2620
Mobile:   +1-858-776-16

RE: GR-1089 Issue 4 and Surge on Ethernet

[emc-p...@ieee.org]

Jim,

I am not sure I understand your explanation of the location of the surge
protection device with respect to the primary or secondary side of the
transformer.  The way I look at this requirement, the key is to *not* provide
a path, direct or through a protection device, back to Ground (C.O. Ground,
Shelf Ground, Frame Ground, Earth Ground, etc.).  If there is surge protection
on either side of the transformer and it is either not referenced to Ground at
all or referenced to Logic Ground only, the exemption can be taken.  While
referencing Logic Ground on the line (surge) side of the transformer or Shelf
Ground on the PHY side of the transformer makes no practical sense, it can
still be done.  Therefore, physical location of the surge protection device
may not necessarily dictate the ability to take this exemption.

Would you agree with that?

Also, can you please clarify on the intent of Section 4.6.9.1.1?  
Referencing
Section 4.6.9.1.1, Equipment Ports With Secondary Protection, was the intent
to label this section, "Equipment Ports With Secondary Protection Not
Referenced to Ground" and only apply that to the longitudinal surges if the
following conditions are met?

1.) The port does not have any secondary voltage-limiting protection 
to ground
2.) The unused pins of the port are not grounded solidly.

...or does this section apply to the metallic surges as well?

Thx,


Joe

~~
Joe Finlayson
Tel:   (508) 357-8273
Fax:  (508) 357-8289
Email: joefinlay...@motorola.com

Motorola, Inc.
Embedded Communications Computing
46 Lizotte Drive
Marlborough, MA 01752
USA
~~


From: JIM WIESE [mailto:jim.wi...@adtran.com] 
Sent: Wednesday, November 29, 2006 3:16 PM
To: Finlayson Joe-G3162C; Gelfand, David; emc-p...@ieee.org
Subject: RE: GR-1089 Issue 4 and Surge on Ethernet

David is correct, it is secondary protection. 

However, it does not cause you to loose the exemption from the metallic test
in your case. 

To loose the exemption, the secondary protection component to ground would
have to be on the opposite side of the transformer than the IC (surged side). 
That is the only way the longitudinal surge could be converted into a metallic
surge.  

In your case, the isolation transformer prevents the conversion from a
longitudinal to metallic surge, and you maintain the test exemption.

Also as a clarification, C.O. ground is only partially correct.  It depends
upon where the equipment is deployed.  Many locations such as EEC's (OSP
cabinets), OSP equipment, and customer premises do not have C.O. grounds. 
GR-1089 covers the entire network.  What is really meant by "ground" is "earth
ground".  In a C.O. this is the same as frame ground, or C.O. ground.  In the
OSP or the customer premises, it is the protective earthing connection on the
equipment which is supposed to be connected to earth ground.  One thing to
remember is that virtually all network equipment has the return side of the
battery voltage connected to  ground, and thus secondary protection components
tied to -48VR for instance are considered grounded. 

Jim
 
Jim Wiese
NEBS Project Manager/Senior Compliance Engineer
ADTRAN, Inc.
901 Explorer Blvd.
Huntsville, AL 35806
256-963-8431
256-714-5882 (cell)
256-963-6218 (fax)
jim.wi...@adtran.com
 


From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Finlayson
Joe-G3162C
Sent: Wednesday, November 29, 2006 12:00 PM
To: Gelfand, David; emc-p...@ieee.org
Subject: RE: GR-1089 Issue 4 and Surge on Ethernet

David,

As that represents a path to Ground, then I would say that the answer is
*Yes*.  Keep in mind that the term "Ground" means "C.O. Ground" when
referencing this topic.

Thx,


Joe

~~
Joe Finlayson
Tel:   (508) 357-8273
Fax:  (508) 357-8289
Email: joefinlay...@motorola.com

Motorola, Inc.
Embedded Communications Computing
46 Lizotte Drive
Marlborough, MA 01752
USA
~~


From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Gelfand, David
Sent: Wednesday, November 29, 2006 12:38 PM
To: emc-p...@ieee.org
Subject: RE: GR-1089 Issue 4 and Surge on Ethernet

Is a diode to ground on lines between the IC and the transformer considered
secondary protection?

Thanks,

David

David Gelfand
Conformity Specialist / Specialiste de conformité
616 Curé-Boivin
Boisbriand, Qc, Canada
J7G 2A7
tel: (450)437-4661x2449
Fax: (450)437-8053
david.gelf...@ca.kontron.com




From: emc-p...@ieee.org [mailto:emc-p...@ieee.org]On Behalf Of Nagel
Michael-amn029
Sent: Wednesday, November 29, 2006 3:55 AM
To: emc-p...@ieee.org
Subject: GR-1089 Issue 4 and Surge on Ethernet


Dear All,

The Issue 4 of GR-1089 contains now (from my understanding) an exemption

for Ethernet from the surge test 1 in Table 4-5 or 4-6 (metallic surge).

Am I right with this interpretation?

Is there any more information available on the history of the metallic 
sur

4 wire resistance measurement lead set

[emc-p...@ieee.org]

Hello,
 
Problem: Would like to evaluate surface conductivity of different types of
metals...
 
1)  Can anyone suggest a "commercial 4 wire lead set" for conducting these
measurements?  
 
2)  Or, commercially available "product or test fixture" for measuring surface
conductivity of 
different metals or coatings there of?
 
3)  How does one measure Galvanic action between two dissimilar metals?
 
Thank you for your time.
 
Regards,
 
Dave Garnier
 

David Garnier 
e GE Health Care 
___ 

David S. Garnier 
Senior Technician 
Functional & CT Engineering 
3000 N. Grandview Ave - M/S W-1250 
Waukesha, Wi. 53188 
Tel: 262.312.7246 
Cel:  414.899.7580 



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RE: Regulatory Compliance stifles innovation?

[emc-p...@ieee.org]

Hello Rich,

I agree with 100%!! Hopefully all the development work being done on the
Hazard Based Safety Standards should get us closer to your EMC example
by defining the end result as opposed to specific construction
requirements. This would allow for innovative designs to be used as long
as they could be proven to be safe.

This would require us, as safety engineers, to perform Fault tree
analysis on every product to identify the possible safety hazards but
this should be done in any case for every product as the current safety
standards try to identify specific safety concerns and as such can't
possibly address every type of product design and hazard the product may
present.

It would be great if we could simplify the standards to level of the EMC
standards as this would reduce grey areas and variations in
interpretations between Agencies but may be more difficult then it
seems

With regard to your example regarding shock hazard it sounds like a good
approach but I can see getting consensus on this from the various
regulatory bodies as a challenge with regards to what type of isolation
is required between hazardous voltage, i.e. mains, and the accessible
voltage. Wouldn't it bring us back to the restrictions of the current
standards of having to define insulation and spacing requirements for
proper isolation??
 
In any case I do agree with you and would love to see the Safety
standards move in this direction.

Best regards,

John


From: Richard Nute [mailto:rn...@san.rr.com] 
Sent: Thursday, November 30, 2006 1:29 PM
To: Tyra, John; emc-p...@ieee.org
Subject: RE: Regulatory Compliance stifles innovation?





Hi John:


> Unfortunately it is difficult for a Safety standard to keep up with 
> new technology and the fairly broad wording makes it open for many 
> different interpretations...

If a safety standard was written as is an EMC standard,
we would not have these problems.

An EMC standard specifies the end-result, namely emissions
not exceeding a certain value.  The standard does not specify what needs
to be done to the equipment to achieve the end- result, although the EMC
report does include a description 
of the various emission control mechanisms.

Today's safety standards do not specify the end-result.  
Instead, the standards specify various constructions deemed 
to make the product safe -- without saying how such 
construction makes the product safe.  The safety report 
describes the constructions, but does not describe how the 
constructions make the product safe.  Consequently, such 
safety standards cannot keep up with new technology.

What if a safety standard specified the end-result, namely
that injury shall be prevented?

This is not as difficult as it may seem.  For example, to prevent
electric shock injury, the end-result would be that accessible parts
shall not exceed a certain value (30 
volts, for example).

In keeping with current requirements, this end-result 
would apply under both normal operating conditions and 
single fault conditions.  As with EMC, the standard would 
not need to describe what needs to be done to the equipment 
to achieve the end-result.

As with EMC, the report would describe the constructions 
that prevent accessible parts from exceeding the limit, 
both for normal operating conditions and single fault 
conditions.

Today, safety engineers don't think this way.  So, an end-result safety
standard would require a huge amount of re-invention of the safety
engineer job!


Best regards,
Rich



Richard Nute
Product Safety Consultant
San Diego

Tel/FAX:  +1-858-592-2620
Mobile:   +1-858-776-1618
e-mail:   ri...@ieee.org
  ri...@alumni.calpoly.edu

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RE: Regulatory Compliance stifles innovation?

[emc-p...@ieee.org]

Hi John:


> Unfortunately it is difficult for a Safety standard to keep
> up with new technology and the fairly broad wording makes it
> open for many different interpretations... 

If a safety standard was written as is an EMC standard,
we would not have these problems.

An EMC standard specifies the end-result, namely emissions
not exceeding a certain value.  The standard does not specify
what needs to be done to the equipment to achieve the end-
result, although the EMC report does include a description 
of the various emission control mechanisms.

Today's safety standards do not specify the end-result.  
Instead, the standards specify various constructions deemed 
to make the product safe -- without saying how such 
construction makes the product safe.  The safety report 
describes the constructions, but does not describe how the 
constructions make the product safe.  Consequently, such 
safety standards cannot keep up with new technology.

What if a safety standard specified the end-result, namely
that injury shall be prevented?

This is not as difficult as it may seem.  For example, to
prevent electric shock injury, the end-result would be
that accessible parts shall not exceed a certain value (30 
volts, for example).

In keeping with current requirements, this end-result 
would apply under both normal operating conditions and 
single fault conditions.  As with EMC, the standard would 
not need to describe what needs to be done to the equipment 
to achieve the end-result.

As with EMC, the report would describe the constructions 
that prevent accessible parts from exceeding the limit, 
both for normal operating conditions and single fault 
conditions.

Today, safety engineers don't think this way.  So, an
end-result safety standard would require a huge amount of
re-invention of the safety engineer job!


Best regards,
Rich



Richard Nute
Product Safety Consultant
San Diego

Tel/FAX:  +1-858-592-2620
Mobile:   +1-858-776-1618
e-mail:   ri...@ieee.org
  ri...@alumni.calpoly.edu

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RE: Regulatory Compliance stifles innovation?

[emc-p...@ieee.org]

Hi Greg:


> I have been trying to think of an example where the standard (IEC
> 60950-1:2001) requires a flame retarded material where no
> possibility of flame exists and cannot come up with one.

I had a product where the main PWB was
vertical and against one side of the
product.  The other side of the product
was about 15 inches away from the board.
(This type of construction is quite 
common in ink-jet printers!)

There was no question the plastic side
next to the board was required to be
flame-retardant material.  However, the
other side, 15 inches away from the PWB,
had no chance of ignition from any failure
on the PWB, but the standard requires the
side to be flame-retardant material.

The power supplied to the PWB was not LPS,
but was not much more than 100 watts.  If
you can imagine a 100-watt light bulb 15
inches away (in a horizontal line) from a
vertically-oriented plastic material, I 
believe you can easily conclude that the 
radiated thermal energy at 15 inches is 
not likely to ignite the plastic material.

In another case, the product was large and
therefore the enclosure was required to be
5V.  No problem.  However, the mains switch
was mounted on a small V0 part that was in
turn attached to the 5V part.  To comply,
the small part had to be changed to 5V.

Not quite to the point of your request,
but these examples show that constructional
standards do not allow for innovative 
design alternatives.  


Best regards,
Rich

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RE: was EN61326 -> standards' effective date interp

[emc-p...@ieee.org]

Ok, so what is the correct interpretation of requirements when the DoP
and/or DoW for a standard, as published on Cenelec.org, do not agree with
what is published on the EU site; i.e., the OJ 

Still confused after all of these years...

thanks,
Brian

> -Original Message-
> From: emc-p...@ieee.org [mailto:emc-p...@ieee.org]On Behalf Of Jon
> Larkin
> Sent: Thursday, November 30, 2006 4:33 AM
> To: emc-p...@ieee.org
> Subject: Fw: EN61326 - recent changes and date product must comply
>
>
> Hey Chris,
>
> I think that you should buy the standard.  Have a look at the Date Of
> Withdrawal (DOW) for when your product should comply with
> that standard,
> although this can be found on the CENELEC website
> (www.cenelec.org, and then
> put the standard number in the box in the top right).
>
> Jon
>
> - Original Message -
> From: "Chris Wells" 
> To: "IEEE Forum (E-mail)" 
> Sent: Thursday, November 30, 2006 12:04 PM
> Subject: EN61326 - recent changes and date product must comply
>
>
> >I did some googling on EN61326 this AM trying to find a
> summary of all the
> >changes in EN61326 and didn't find any detail.
> > Are there other changes to consider besides the higher RF range?
> > Anyone have a web url to share?
> >
> > Date of compliance?
> > I have a product that already is tested to EN61326  - then
> how long before
> > I must comply to the new version?
> > Isn't there a grace period?
> >
> > Thanks
> >
> > Chris Wells
> >
> >
> >
> >
>

-

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Fw: EN61326 - recent changes and date product must comply

[emc-p...@ieee.org]

Hey Chris,

I think that you should buy the standard.  Have a look at the Date Of 
Withdrawal (DOW) for when your product should comply with that standard, 
although this can be found on the CENELEC website (www.cenelec.org, and then 
put the standard number in the box in the top right).

Jon

- Original Message - 
From: "Chris Wells" 
To: "IEEE Forum (E-mail)" 
Sent: Thursday, November 30, 2006 12:04 PM
Subject: EN61326 - recent changes and date product must comply


>I did some googling on EN61326 this AM trying to find a summary of all the 
>changes in EN61326 and didn't find any detail.
> Are there other changes to consider besides the higher RF range?
> Anyone have a web url to share?
>
> Date of compliance?
> I have a product that already is tested to EN61326  - then how long before 
> I must comply to the new version?
> Isn't there a grace period?
>
> Thanks
>
> Chris Wells
>
>
>
>
>
>
>
>> Ian
>> Yes - the 2006 edition of EN61326-1 goes up to 2.7GHz in 3 field strength
>> bands. This is along with other requirements such as voltage sag testing.
>>
>> Ian Gordon
>>
>>
>
> Forum members
>
>
> With EN61000-6-2 : 2005 having moved the Radiated Immunity limit to 2.7GHz 
> and having been informed through these listings that the IEC version of 
> EN61326 is moving in the same direction could anyone inform me  :
>
> If the EN version is moving that way and when.
> If the IEC version calling for this new upper limit is published.
>
> Thanks for your help in advance
>
> Ian White
> -
> 
> This message is from the IEEE Product Safety Engineering Society
> emc-pstc discussion list.Website:  http://www.ieee-pses.org/
>
> To post a message to the list, send your e-mail to emc-p...@ieee.org
>
> Instructions:  http://listserv.ieee.org/request/user-guide.html
>
> List rules: http://www.ieee-pses.org/listrules.html
>
> For help, send mail to the list administrators:
>
> Scott Douglas   emcp...@ptcnh.net
> Mike Cantwell   mcantw...@ieee.org
>
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>
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> David Heald:emc-p...@daveheald.com
>
> All emc-pstc postings are archived and searchable on the web at:
>
>http://www.ieeecommunities.org/emc-pstc
>
>
> -- 
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.5.430 / Virus Database: 268.15.2/559 - Release Date: 30/11/2006 
> 05:07
>
> 

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RE: EN61326 - recent changes and date product must comply

[emc-p...@ieee.org]

I haven't done a line by line comparison, so cannot comment on the changes.

However, you have until 1st Frebruary 2009 to comply, after which the
conflicting standard will be withdrawn.

Best regards 

Neil R. Barker CEng MIET FSEE MIEEE 
Manager 
Quality Engineering 
e2v technologies (uk) ltd 
106 Waterhouse Lane 
Chelmsford 
Essex CM1 2QU 
UK 

Tel: (+44) 1245 453616 
Fax: (+44) 1245 453571 
Mob: (+44) 7801 723735 




From: Chris Wells [mailto:cdwe...@adelphia.net]
Sent: 30 November 2006 12:04
To: IEEE Forum (E-mail)
Subject: EN61326 - recent changes and date product must comply


I did some googling on EN61326 this AM trying to find a summary of all the 
changes in EN61326 and didn't find any detail.
Are there other changes to consider besides the higher RF range?
Anyone have a web url to share?

Date of compliance?
I have a product that already is tested to EN61326  - then how long before I

must comply to the new version?
Isn't there a grace period?

Thanks

Chris Wells







> Ian
> Yes - the 2006 edition of EN61326-1 goes up to 2.7GHz in 3 field strength
> bands. This is along with other requirements such as voltage sag testing.
>
> Ian Gordon
>
>

Forum members


With EN61000-6-2 : 2005 having moved the Radiated Immunity limit to 2.7GHz 
and having been informed through these listings that the IEC version of 
EN61326 is moving in the same direction could anyone inform me  :

If the EN version is moving that way and when.
If the IEC version calling for this new upper limit is published.

Thanks for your help in advance

Ian White 

-

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EN61326 - recent changes and date product must comply

[emc-p...@ieee.org]

I did some googling on EN61326 this AM trying to find a summary of all the 
changes in EN61326 and didn't find any detail.
Are there other changes to consider besides the higher RF range?
Anyone have a web url to share?

Date of compliance?
I have a product that already is tested to EN61326  - then how long before I 
must comply to the new version?
Isn't there a grace period?

Thanks

Chris Wells







> Ian
> Yes - the 2006 edition of EN61326-1 goes up to 2.7GHz in 3 field strength
> bands. This is along with other requirements such as voltage sag testing.
>
> Ian Gordon
>
>

Forum members


With EN61000-6-2 : 2005 having moved the Radiated Immunity limit to 2.7GHz 
and having been informed through these listings that the IEC version of 
EN61326 is moving in the same direction could anyone inform me  :

If the EN version is moving that way and when.
If the IEC version calling for this new upper limit is published.

Thanks for your help in advance

Ian White 

-

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Rated Voltage for a Safety Ceramic Capaciors

[emc-p...@ieee.org]

Dear Experts,
 

One of our hardware design engineers comes up with a question for rated
voltage for a capacitor.  

Under the second page (Page 19) of the datasheet found at 

http://www.avxcorp.com/docs/Catalogs/safecc.pdf, the rated voltage for 61V is
different when using as a X1 and when using as an Y1.  The question is: for a
same capacitor, why is the rated voltage different due to its usage (X1 400VAC
vs Y1 250VAC)?  

Thank you for your time and look forward to your help. 

Best regards,

Grace Lin

Sr. Compliance Engineer

Crestron Electronics, Inc.

6 Volvo Drive

Rockleigh, NJ 07647

USA

  www.crestron.com 

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Antenna Pre-amps

[emc-p...@ieee.org]

Thanks for the many replies that I received.

Bob Heller
3M EMC Laboratory, 76-1-01
St. Paul, MN 55107-1208
Tel:  651- 778-6336
Fax:  651-778-6252
=

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Re: 63A conducted emission/immunity testing in the UK

[emc-p...@ieee.org]

In message 
<5d39f9c94199f64fa82e5809c702aa7c01c...@z-160-100-30-229.est.ibm.com>, 
"Gordon,Ian"  writes
>Can anyone suggest a UK supplier/manufacturer of the following, 
>suitable for
>connection to a 3 phase (415V) supply?
>Mains LISN
>Mains CDN
>Fast transient coupler and
>Surge tester

Try Richard Marshall Ltd., at least for the LISN and CDN.
-- 
John Woodgate

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