Doug,
Not sure how we appear to be on the opposite side of the stick here.
Believe it or not I support almost all of the NRTL compliance engineers I have
worked with. They are like any group of people some are very good some should
quit consuming oxygen at the first opportunity
The reason for the Part 15 residential (Class B) limit is to protect
reception, and the levels prescribed are (arguably) low enough to do so. If
we allow higher levels, we are asking for service calls and perhaps
official attention. But (unless I am mistaken) it is now the USER who
responsible
Just making a quick check here. I'm seeing some product brochures out
indicating some of these home units are class A. Am I missing something here,
shouldn't that be class B. The fact its phone stuff (also carries the FCC part
68 stuff) can't override this classification correct?
Time certainly couldn't account for wide ranging humidity
or altitude, but perhaps lessor humidity and air pressure
changes. The time may have more to do with settling
capacitive effects first.
Stephen
At 10:38 AM 3/15/2002, MCA Compliance wrote:
These factors are certainly all relevant,
Regarding Paschen's Law:
http://home.earthlink.net/~jimlux/hv/hvmain.htm
http://home.earthlink.net/~jimlux/hv/paschen.htm
Stephen
At 12:51 PM 3/15/2002, Doug McKean wrote:
I've done my own testing and researched the thing as well.
I think we've had some serious discussions here
I've done my own testing and researched the thing as well.
I think we've had some serious discussions here about this
subject in the past. If the archives are available, it would
be beneficial to go through them. Also, get a little hipot
tester from any of the hipot mfrs for your own bench
Gary,
I can go along with the documentation hunt as well.
And I can understand that their approval cycle would
probably increase by a factor of x10 (I'm not joking)
if they had to do all the research to the parts themselves.
I believe that's really what's at the bottom of it all.
But,
Hi Guys
My wording may have been put together in haste however, I think the
important part of the directive is the word OR. The manufacturer OR his
authorised representative, established within the community. I had always
beleived this was interpreted as one or the other must be within the EEC
The Commission has said the same thing in their explainatory document.
http://europa.eu.int/comm/enterprise/newapproach/legislation/guide/legislati
on.htm
Note: this URL is long and may be cut into two sections when you receive
this e-mail. If so, just join the two sections back togther to
As a member of CENELEC, Switzerland uses ENs. I understand Poland uses EN
55022.
Richard Woods
Sensormatic Electronics
Tyco International
-Original Message-
From: cecil.gitt...@kodak.com [mailto:cecil.gitt...@kodak.com]
Sent: Friday, March 15, 2002 8:08 AM
To:
Regarding the snippet below paralleling the bulk cap with a ceramic
addresses differential mode noise such as the vacuum cleaner, but it doesn't
help against common mode noise that the cm choke and snap-on ferrite sleeve
address. Line to ground or Y-caps will work with the cm choke and snap-on
I read in !emc-pstc that MCA Compliance bally...@iolfree.ie wrote (in
nbbblhpagldfkfbcdencaemojjac.bally...@iolfree.ie) about 'creepage v
breakdown voltage', on Fri, 15 Mar 2002:
How did they arrive at 2.5 mm ???
IEC TC74, responsible for IEC60950, didn't arrive at it. There is a
special
Hello,
According to the latest version of the Telecommunication Labelling Notice
2001, products in the Category A50 are deemed to comply with ACA
TS-001-1997 and AS/ACIF S043-2001. No problem for TS-001, but S043 needs
Compliance level 3 only since January 1rst 2002.
The general approach is
Remember that some of that distance, I believe, accounts for when the
boards get dirty, and the pollutants build up and reduce the spacings. When you
test the boards during the evaluation they are almost always clean with no
pollution build-up.
Gary
-Original Message-
Doug,
I have no problem doing just that with my projects. The online data
thing gives away the source so we are talking about the same folks - but
different offices. Although I know that the engineer involved in my projects
pulls copies of the full reports for the device, as
Kim,
I believe the Part you desire is 47 CFR 15.231 (Part 15, clause 231)
...the intentional radiator is restricted to the transmission of a control
signal such as those used with alarm systems, door openers, remote openers,
etc. The fundamental is allowed a level of 3,700 - 12,500 uV/m from
Try this.
For flat electrodes, at sea level, and normal temperatures;
eliminating such factors as humidity, dust, illumination, and
the electrode materials; the molecules of the gases that
compose common air, get ionized in the presence of an
electric field of about 30KV/cm.
So, since -
Doing high voltage power supplies we found we always got in trouble using
20,000 V/in and things worked well when we kept below 10,000 V/in.
Metric that's 790 V/mm and 390 V/mm
This was free air and not some kind of pointy structure.
- Robert -
Robert A. Macy,
*snippped from Stephen Phillips email**
The geometry of the surface across which the potential
is laid matters too (curves, points, parallel planes),
doesn't it. Again, maybe the committee just added
guaranteed slop.
Correct me if I am wrong, but I do not believe the statement below is entirely
correct. It is my understanding (per EMC directive and published guidelines)
that the Manufacturer or Authorized Representative is responsible for affixing
the CE marking and drawing up the DoC and that only the
Hi All,
The Creepage and clearance specifications take into account the long term
degradation of spacings due to environmental conditions. Just because it will
pass the test today when it is clean and pure does not mean that this condition
will last forever.
Scott
MCA Compliance wrote:
Peter
I was looking into this a few weeks ago also and found similar results
experimentally as other posters have mentioned. The only voltage per inch
spec I was able to come up with was in the IPC specs but they were way out
of whack! 0.12 mils per volt or more meaning that 2121 Vdc distance that
Hi All,
I have tested ITE products to the FCC, EN55022 and EN55024 Standards.
Does anyone know what additional EMC approvals and documentation is
required for Poland, Russia
and Switzerland?
Thanks for your help
Cecil
---
This message is from
Try downloading from this location:
http://www.fcc.gov/oet/info/rules/
Richard Woods
Sensormatic Electronics
Tyco International
-Original Message-
From: Kim Boll Jensen [mailto:kimb...@post7.tele.dk]
Sent: Friday, March 15, 2002 7:36 AM
To: treg; EMC-PSTC
Subject: SDR in the US
Hi
Humidity matters.
Some years back, when doing some experiments
around this subject - I too was surprised at just how
much voltage different gaps could bear, such that the
standard seemed gross overkill. But in a less than
purely scientific way, I decided to breath (just breath,
not blow)
Peter
I agreee with your comment, but, I have seen lots of boards (material group
III) pass high pot tests at 1.5kV with only 2 mm creepage on the boards.
yet, 950 specifies 2.5mm for basic insulation.
This is why I am after some independent experimental test data correlating
creepage and
Brian,
Your PCB manufacturer should be able to tell you what spacings to keep in
order to withstand the test voltages. It all depends on the base material
used for the PCB which all have different dielectric strength properties.
Remember, the standards reference a minimum creepage distance AND
One clear piece of evidence is that safety standards committees always
specify much larger creepage and clearance distances for externaly supplied
hazardous voltages than for those generated within a product. A good
example are the two sets of tables in IEC or EN 60 950. This is to
accomodate
I beleive the change in stance is due to the change in requirement regarding
a European presence. Under the EMC directive, the person making a DOC and
placing the goods on the market would be an EU resident. The RTTE allows
parties outside of the EU to make the DOC and hold the Technical file,
does data exist which correlates creepage distance on a pcb with
hi-potential test voltage it should withstand ?
for example, I know 60950 sugests a test voltage of 1500Vrms for 1 minute
and a creepage of 2.5mm (material group III) for basic insulation.
How did they arrive at 2.5 mm ???
Brian
Alex,
I am currently testing some lithium ion battery pack for a major
international renowned manufacturer. None of their lithium ion battery
packs are vented and many are already Accessory Listed to UL60950. This
leads me to believe that venting is not a problem with such
battery packs.
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