Safety of electronic equipment?

[Paul Hovnanian P.E.]

Active8 wrote:

[snip]

Frontpage bloats way more than dreamweaver.

Front Page is for wimps. Real developers build web pages with vi. ;-)

--
Paul Hovnanian mailtoaul@Hovnanian.com
note to spammers: a Washington State resident
------------------------------------------------------------------
Parity on, dudes!

 

[The little lost angel]

On Fri, 12 Dec 2003 21:28:29 GMT, Active8
<mTHISREMOVEcolasono@earthlink.net,invalid> wrote:

Oh, so the reversed UL means the PSU is a component and safe as one
but not as a retail/finished product? If there's a forward UL label,
then it means a finished product suitable for retail?


Spehro didn't get that joke and maybe it was unintentional, but I
understand what you didn't say. That was good. 2 approved
components in an approved cabinet and it isn't approved.

Erm, it was definitely unintentional... though I think I know what the
joke is, I'm not 100% sure that's the joke PpPp

--
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[The little lost angel]

On Fri, 12 Dec 2003 19:47:44 +0000, John Woodgate
<jmw@jmwa.demon.contraspam.yuk> wrote:

You are asking in the wrong newsgroup, although I think it's very
disquieting that none of these designers know anything much about safety
standards.

The appropriate news group is sci.engineering.electronics.compliance,
but even better is the IEEE emc-pstc mailgroup.

Thanks for the directions!

Unless perhaps you are dealing with equipment for hazardous atmospheres,
there are no 'levels' in any electrical product safety standards that I
have ever seen. I think the salesman was emitting pure BS.

I don't think it's got anything to do with atmospheres definitely.

Though I must admit, I wasn't right next to them so I could have
misheard the levels reference and he could have been talking about the
CSA or something.
--
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[John Woodgate]

I read in sci.electronics.design that Active8 <mTHISREMOVEcolasono@earth
link.net> wrote (in <MPG.1a43fd0987cf729198969e@news.east.earthlink.net>
) about 'Safety of electronic equipment?', on Fri, 12 Dec 2003:

2 approved components in
an approved cabinet and it isn't approved.

Yes. For example, separately they may remain cool, but together in the
box they get far too hot.
--
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
Interested in professional sound reinforcement and distribution? Then go to
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!

 

[John Woodgate]

I read in sci.electronics.design that Active8 <mTHISREMOVEcolasono@earth
link.net> wrote (in <MPG.1a440df7f65b95c9896a1@news.east.earthlink.net&gt
about 'Safety of electronic equipment?', on Fri, 12 Dec 2003:

Chances are, the people that look that crap up aren't good enough to be
designers.

Safety and EMC compliance have to be *designed in*. Its very costly and
time-consuming to alter 'finished' designs that don't comply. So
competent designers need to 'look that crap up' and thoroughly
understand it.

People who do safety and EMC *testing* may or may not be competent
designers, but they are not employed to design stuff. They do need to
understand what they are doing, and to be meticulously accurate in
reporting results.
--
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
Interested in professional sound reinforcement and distribution? Then go to
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!

 

[Active8]

On Sat, 13 Dec 2003 02:16:58 GMT, a?n?g?e?
l@lovergirl.lrigrevol.moc.com said...

On Fri, 12 Dec 2003 21:28:29 GMT, Active8
mTHISREMOVEcolasono@earthlink.net,invalid> wrote:

Oh, so the reversed UL means the PSU is a component and safe as one
but not as a retail/finished product? If there's a forward UL label,
then it means a finished product suitable for retail?

it would be safe to sell as a "finished" "retail" (or otherwise)

"component product" (semantics), but once it's combined with
another component, all bets are off.

Spehro didn't get that joke and maybe it was unintentional, but I
understand what you didn't say. That was good. 2 approved
components in an approved cabinet and it isn't approved.

Erm, it was definitely unintentional... though I think I know what the
joke is, I'm not 100% sure that's the joke PpPp

PpPp ?? Is that some new kind of emoticon?

I figure it's typical of bureaucrat types that justify their

meaningless existences with reams of drivel that require a company
to expend much resources just to interpret. Probably easier to copy
what others have done, send it out to a lab and fix what's wrong.

But to require that an assembly of approved parts must be approved
as an assembly does make sense. A wire may be an acceptable
conductor and connected to an approved swtch or PS, but not if it's
used to carry more current than it's rated for.

I was thinking more in terms of a computer power supply connected
to a moterboard, drive, fan, etc. Pretty benign, but without
another sticker on the case, there's no way for a consumer to tell
if the whole shebang is safe, not that they'd look. So there's laws
in place to protect the consumer. Too many, in fact.

Mike

 

[Active8]

On Fri, 12 Dec 2003 17:42:40 -0800, Paul@Hovnanian.com said...

Active8 wrote:

[snip]


Frontpage bloats way more than dreamweaver.

Front Page is for wimps. Real developers build web pages with vi. ;-)


I like vi.:wq

mike

 

[Active8]

On Sat, 13 Dec 2003 08:15:43 +0000, jmw@jmwa.demon.contraspam.yuk
said...

I read in sci.electronics.design that Active8 <mTHISREMOVEcolasono@earth
link.net> wrote (in <MPG.1a440df7f65b95c9896a1@news.east.earthlink.net&gt
about 'Safety of electronic equipment?', on Fri, 12 Dec 2003:

Chances are, the people that look that crap up aren't good enough to be
designers.


Safety and EMC compliance have to be *designed in*. Its very costly and
time-consuming to alter 'finished' designs that don't comply. So
competent designers need to 'look that crap up' and thoroughly
understand it.

People who do safety and EMC *testing* may or may not be competent
designers, but they are not employed to design stuff. They do need to
understand what they are doing, and to be meticulously accurate in
reporting results.

I suppose even in a large company, a (possibly pointy haired)

manager type who writes the specs would just delegate the
responsibility of meeting them to the designer, but the company
would have the resources to provide that info.

At least there's that compliance NG. But as the OP said, she found
a site that cost a few $100s to access. That's not bad considering
Percom's FCC database is $400 and a FCC broadcast station licensing
info CD is $1200. Not good for the OP though since she just wants
to be able to cut through the sales hype.

Mike

 

[John Woodgate]

I read in sci.electronics.design that Active8 <mTHISREMOVEcolasono@earth
link.net> wrote (in <MPG.1a44e511ac1002059896b5@news.west.earthlink.net>
) about 'Safety of electronic equipment?', on Sat, 13 Dec 2003:

I suppose even in a large company, a (possibly pointy haired) manager
type who writes the specs

Hey, I help write the standards, and any pointy-hairs get short shrift
from me and my colleagues. While some standards ARE badly written (and
some of us keep pointing that out, in the hope that eventually something
will be done about it), we spend a LOT of time trying to make the words
as simple as possible and unlikely to be misinterpreted.

I say 'unlikely', from experience of how ingenious people are at
misinterpreting, usually so that either the requirement is impossible to
meet or makes no sense. They don't even consider that if that is the
result, *their interpretation* may be the cause, not incompetent
standards writing.
--
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
Interested in professional sound reinforcement and distribution? Then go to
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!

 

[The little lost angel]

On Fri, 12 Dec 2003 18:42:27 GMT, Spehro Pefhany
<speffSNIP@interlogDOTyou.knowwhat> wrote:

They could be using another testing lab with a different logo and
perhaps testing to different standards. I'm not sure what offical
testing is required in your steamy little city-state.

Maybe this is what they have?
http://www.spring.gov.sg/portal/images/safetymark.jpg

Don't think so. I did ask another friend of mine about this since he
used to work in that board/agency. While he's not doing the testing,
he said as far as he knows, they don't test for components, only
finished products. So for things that get assembled into a final
widget, which my friend's company is doing, the local safety board
isn't bothered with what's inside... even though the item is being
sold as a standalone product.

I don't understand the logic to why they demand the finished widget to
be tested but the components in it, while sold in retail doesn't
--
L.Angel: I'm looking for web design work.
If you need basic to med complexity webpages at affordable rates, email me
Standard HTML, SHTML, MySQL + PHP or ASP, Javascript.
If you really want, FrontPage & DreamWeaver too.
But keep in mind you pay extra bandwidth for their bloated code

 

[The little lost angel]

On Sat, 13 Dec 2003 13:58:28 GMT, Active8
<mTHISREMOVEcolasono@earthlink.net,invalid> wrote:

At least there's that compliance NG. But as the OP said, she found
a site that cost a few $100s to access. That's not bad considering
Percom's FCC database is $400 and a FCC broadcast station licensing
info CD is $1200. Not good for the OP though since she just wants
to be able to cut through the sales hype.

Nobody's seem to be active in the compliance NG.

I think it's really quite terrible that regulations and standards
meant to protect consumers... cannot be accessed by consumers to
figure out if what they are being sold is actually safe.

I mean fine if they want to keep the exact values and tests involved
secret. But at the very least put something somewhere so that we can
tell for the listed product XYZ, it passes UL-xxxxx with the following
criteria of a) safe for abc usage b) safe for use in efg situation
c)not safe for blah blah blah

After popping in several of the brand names available locally for PSU,
I actually came across one that says the +5v and +12v energy level are
at hazardous levels. Now am I supposed to be concerned if I buy this
thing or am I supposed to be assured that since it passed UL, it's
safe even though they have this warning??


--
L.Angel: I'm looking for web design work.
If you need basic to med complexity webpages at affordable rates, email me
Standard HTML, SHTML, MySQL + PHP or ASP, Javascript.
If you really want, FrontPage & DreamWeaver too.
But keep in mind you pay extra bandwidth for their bloated code

 

[Spehro Pefhany]

On Sat, 13 Dec 2003 15:51:47 GMT, the renowned
a?n?g?e?l@lovergirl.lrigrevol.moc.com (The little lost angel) wrote:

After popping in several of the brand names available locally for PSU,
I actually came across one that says the +5v and +12v energy level are
at hazardous levels. Now am I supposed to be concerned if I buy this
thing or am I supposed to be assured that since it passed UL, it's
safe even though they have this warning??

It is NOT unconditionally safe. You could EASILY start a fire with the
power coming from a regular PC PSU. A dead short will trip the
protection and an open won't do anything bad, but a bit of nichrome or
stainless-steel wire..

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[John Fields]

On Sat, 13 Dec 2003 15:51:47 GMT, a?n?g?e?l@lovergirl.lrigrevol.moc.com
(The little lost angel) wrote:

Nobody's seem to be active in the compliance NG.

I think it's really quite terrible that regulations and standards
meant to protect consumers... cannot be accessed by consumers to
figure out if what they are being sold is actually safe.
---

That's not quite true. Standards are available to anyone who wants
them. However, in the case of UL and similar organizations where the
standards were developed with private funds, those documents are
proprietary and copyrighted, are not in the public domain, and must be
paid for. The same may even be true for some standards developed with
public funds. It's been a while since I quoted any military equipment
and got the spec's as part of the bid package, so I don't know any more.
---

I mean fine if they want to keep the exact values and tests involved
secret. But at the very least put something somewhere so that we can
tell for the listed product XYZ, it passes UL-xxxxx with the following
criteria of a) safe for abc usage b) safe for use in efg situation
c)not safe for blah blah blah

After popping in several of the brand names available locally for PSU,
I actually came across one that says the +5v and +12v energy level are
at hazardous levels. Now am I supposed to be concerned if I buy this
thing or am I supposed to be assured that since it passed UL, it's
safe even though they have this warning??

---
If there's any question as to the appropriateness of the device for its
intended use or if you're concerned with the interpretation of its
specifications you should contact the manufacturer for clarification
and/or get copies of the various standards to which it's supposed to
adhere, read them, and put the matter to rest.

--
John Fields

 

[The little lost angel]

On Sat, 13 Dec 2003 16:02:31 GMT, Spehro Pefhany
<speffSNIP@interlogDOTyou.knowwhat> wrote:

It is NOT unconditionally safe. You could EASILY start a fire with the
power coming from a regular PC PSU. A dead short will trip the
protection and an open won't do anything bad, but a bit of nichrome or
stainless-steel wire..

Well, that

But assuming a normal situation and not an intentional one, would the
warning be just an extra we-better-put-this-in-case-of-lawsuits kind
of footnote?

--
L.Angel: I'm looking for web design work.
If you need basic to med complexity webpages at affordable rates, email me
Standard HTML, SHTML, MySQL + PHP or ASP, Javascript.
If you really want, FrontPage & DreamWeaver too.
But keep in mind you pay extra bandwidth for their bloated code

 

[The little lost angel]

On Sat, 13 Dec 2003 10:30:02 -0600, John Fields
<jfields@austininstruments.com> wrote:

If there's any question as to the appropriateness of the device for its
intended use or if you're concerned with the interpretation of its
specifications you should contact the manufacturer for clarification
and/or get copies of the various standards to which it's supposed to
adhere, read them, and put the matter to rest.

Heehee, somehow I doubt manufacturers would be bothered to reply to
some nobody just out to satisfy curiousity. Plus even if they do, I
doubt they would admit to any fault or dubious characteristics...
after all, they are supposed to be selling that stuff. It would just
be like when I asked a vendor about their power supply, surprisingly
light and cheap and claiming over 400W in output... pPp

--
L.Angel: I'm looking for web design work.
If you need basic to med complexity webpages at affordable rates, email me
Standard HTML, SHTML, MySQL + PHP or ASP, Javascript.
If you really want, FrontPage & DreamWeaver too.
But keep in mind you pay extra bandwidth for their bloated code

 

[Active8]

On Sat, 13 Dec 2003 15:31:50 +0000, jmw@jmwa.demon.contraspam.yuk
said...

I read in sci.electronics.design that Active8 <mTHISREMOVEcolasono@earth
link.net> wrote (in <MPG.1a44e511ac1002059896b5@news.west.earthlink.net
) about 'Safety of electronic equipment?', on Sat, 13 Dec 2003:

I suppose even in a large company, a (possibly pointy haired) manager
type who writes the specs

Hey, I help write the standards, and any pointy-hairs get short shrift
from me and my colleagues. While some standards ARE badly written (and
some of us keep pointing that out, in the hope that eventually something
will be done about it), we spend a LOT of time trying to make the words
as simple as possible and unlikely to be misinterpreted.

I say 'unlikely', from experience of how ingenious people are at
misinterpreting, usually so that either the requirement is impossible to
meet or makes no sense. They don't even consider that if that is the
result, *their interpretation* may be the cause, not incompetent
standards writing.

Did you just misinterpret?

Who said anything about poorly written standards? I said "spec" and
nothing more. As in, "Hey Mike, this needs to be UL approved for
consumer use." Whatever. and the designer gets to figure it out.

Mike

 

[John Fields]

On Sat, 13 Dec 2003 17:14:22 GMT, a?n?g?e?l@lovergirl.lrigrevol.moc.com
(The little lost angel) wrote:

On Sat, 13 Dec 2003 10:30:02 -0600, John Fields
jfields@austininstruments.com> wrote:

If there's any question as to the appropriateness of the device for its
intended use or if you're concerned with the interpretation of its
specifications you should contact the manufacturer for clarification
and/or get copies of the various standards to which it's supposed to
adhere, read them, and put the matter to rest.

Heehee, somehow I doubt manufacturers would be bothered to reply to
some nobody just out to satisfy curiousity. Plus even if they do, I
doubt they would admit to any fault or dubious characteristics...
after all, they are supposed to be selling that stuff. It would just
be like when I asked a vendor about their power supply, surprisingly
light and cheap and claiming over 400W in output... pPp

---
Well, then, I guess no matter how hard you try you'll never get the
answers you want... :-(

--
John Fields

 

[Active8]

On Sat, 13 Dec 2003 15:51:47 GMT, a?n?g?e?
l@lovergirl.lrigrevol.moc.com said...

On Sat, 13 Dec 2003 13:58:28 GMT, Active8
mTHISREMOVEcolasono@earthlink.net,invalid> wrote:
At least there's that compliance NG. But as the OP said, she found
a site that cost a few $100s to access. That's not bad considering
Percom's FCC database is $400 and a FCC broadcast station licensing
info CD is $1200. Not good for the OP though since she just wants
to be able to cut through the sales hype.

Nobody's seem to be active in the compliance NG.

Arrrggghhhh!

I think it's really quite terrible that regulations and standards
meant to protect consumers... cannot be accessed by consumers to
figure out if what they are being sold is actually safe.

Agreed.

I mean fine if they want to keep the exact values and tests involved
secret.

I migrated a database for a company onece. They weren't worried
about the test methods getting out, just the process info. The test
methods were there to meet ISO compliance. Stuff like flammability
tests and scratch, shear, and color tests on plastics.

But at the very least put something somewhere so that we can
tell for the listed product XYZ, it passes UL-xxxxx with the following
criteria of a) safe for abc usage b) safe for use in efg situation
c)not safe for blah blah blah

I, too, think it should be in the public domain. Freedom of
information act and all. Problem is, take Percom, for instance.
They take a hard to read FCC freq database and organize it so it's
easy to use. Then they charge for the convienience. Before inet,
you'd have to buy books on UL standards or get lucky at a library.

After popping in several of the brand names available locally for PSU,
I actually came across one that says the +5v and +12v energy level are
at hazardous levels. Now am I supposed to be concerned if I buy this
thing or am I supposed to be assured that since it passed UL, it's
safe even though they have this warning??

Good question.

Mike

 

[John Woodgate]

I read in sci.electronics.design that The little lost angel <a?n?g?e?l@l
overgirl.lrigrevol.moc.com> wrote (in <3fdb34af.45424446@news.pacific.ne
t.sg&gt about 'Safety of electronic equipment?', on Sat, 13 Dec 2003:

Nobody's seem to be active in the compliance NG.

There is less activity at weekends, of course, but there are 10-15
articles a day during the week.

I think it's really quite terrible that regulations and standards meant
to protect consumers... cannot be accessed by consumers to figure out if
what they are being sold is actually safe.

The MARKING is your assurance that the product is safe.

I mean fine if they want to keep the exact values and tests involved
secret. But at the very least put something somewhere so that we can
tell for the listed product XYZ, it passes UL-xxxxx with the following
criteria of a) safe for abc usage b) safe for use in efg situation c)not
safe for blah blah blah

If you can buy the product as a member of the general public, you can be
assured that it is safe for normal household and commercial use. There
are special requirements for use on ships and aircraft and in hazardous
atmospheres, but products in these categories are available only from
specialist outlets.

Your concern is understandable, but is not realistic.

After popping in several of the brand names available locally for PSU, I
actually came across one that says the +5v and +12v energy level are at
hazardous levels. Now am I supposed to be concerned if I buy this thing
or am I supposed to be assured that since it passed UL, it's safe even
though they have this warning??

If you want to delve into this properly, you need to buy, read and
understand UL1950 or whichever safety standard applies. The 'hazard' in
this case is that *if the 5 V or 12 v supply were short-circuited*
through a resistance within critical range of values, there might be
enough energy released to cause overheating. If you use the product
responsibly, there is no problem. But people who don't know this
shouldn't really be buying the product anyway.
--
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
Interested in professional sound reinforcement and distribution? Then go to
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!

 

[John Woodgate]

I read in sci.electronics.design that Active8 <mTHISREMOVEcolasono@earth
link.net> wrote (in <MPG.1a4516b36a1b077c9896bc@news.west.earthlink.net>
) about 'Safety of electronic equipment?', on Sat, 13 Dec 2003:

Did you just misinterpret?

I don't think so.

Who said anything about poorly written standards? I said "spec" and
nothing more. As in, "Hey Mike, this needs to be UL approved for
consumer use." Whatever. and the designer gets to figure it out.

What do you mean by 'spec'? I assumed that you meant whichever UL
standard (such as UL1950) applies. I couldn't see any other
interpretation that made sense.
--
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
Interested in professional sound reinforcement and distribution? Then go to
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!