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Safety of electronic equipment?

Discussion in 'Electronic Basics' started by The little lost angel, Dec 11, 2003.

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  1. Hi, I got a question about the safety certifications of electronics
    equipment.

    It happens that I was at my friend's office when some guy was peddling
    his computer/electronic equipment to him. One thing that caught my
    attention was when my friend mentioned that they are using X brand and
    see no reason to change, this sales fellow claims that X brand is UL
    certified at level 6(I think, wasn't next to them) while theirs is
    certified at level 3 (I think). Thus X brand is more dangerous to
    install/use compared to their brand.

    I think it's just sales puff but I don't know much about this safety
    thingy (locally, they don't seem to care). Though my common sense says
    if UL has passed the equipment for safety, then shouldn't it not
    matter whether it's what level?

    --
    L.Angel: I'm looking for web design work.
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  2. Active8

    Active8 Guest

    Frontpage bloats way more than dreamweaver.
     
  3. Erm? Sorry, I'm not sure how to decode this in reference to my
    question...

    --
    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
     
  4. Active8

    Active8 Guest

    Then you really are lost ;-) I never miss an opportunity to slam
    FP.

    I'd have tried google. You would've had an answer by now instead of
    having to read my OT response. Find out what the different levels
    of rating are. You'll probably find there's some difference in
    flamability rating and insulation resistance or something. So maybe
    the higher rating is for use in a different environment and it's
    overkill for home/office use. As you said, "sales fluff". I call it
    bs. But since we don't know what type of appliance you're talking
    about or where it will be used, ain't gonna be much of an answer
    forthcoming.

    hmm... I just had a look at this Taiwanese computer PS I'm using to
    power a circuit. It doesn't even have a UL sticker, just SA and
    that backward RU thingy. The old computer it came out of never
    fried and it hasn't fried since I cannabalized it, so I guess it's
    safe if I don't spill anything on it.

    Mike
     
  5. Rich Grise

    Rich Grise Guest

    Um, that backward UR thingy _is_ the UL sticker. They
    changed it some years ago. (or it's a different kind
    of cert, or something. I'd have to look it up.) :)

    Cheers!
    Rich
     
  6. Active8

    Active8 Guest

    I thought that might be the case, but you say "some" years ago. I
    bought the system... well... it was out of a 386 box. It was bought
    used 9 yrs ago. I just dusted off the fan grill :)

    I'll probably come across that info if I ever need to look into it.

    Mike
     
  7. It's their logo for *component* approval. The PSU isn't a finished
    product.

    Best regards,
    Spehro Pefhany
     
  8. 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?

    --
    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
     
  9. Hi, angel. Yes, that's right. Often with "C" and/or "US: meaning that
    it's been tested by UL to meet Canadian and/or US standards. Note that
    AC adapters (wall warts) are considered finished products. You'll also
    see the backwards UR on disk drives, safety-rated capacitors etc.

    Best regards,
    Spehro Pefhany
     
  10. Heehee, me bad, I messed up my siggy, so it didn't show up in that
    post you were replying to.
    I've been looking, the places that has the UL standards documents
    demand a few hundred bucks before they'll let me at them.

    Searching specifically for UL level 6/six usually brings me to product
    specifications and the level 6 usually refers to CSA instead of UL. :(
    Since you mention a Taiwanese PSU, let's use that as an example. After
    all, I would like to learn how to figure this stuff out on a generic
    basis rather than knowing only how to read the info for say a
    soldering iron :pPPp
    I looked up UL for two famous brands, Enermax and Antec.
    http://database.ul.com/cgi-bin/XYV/...n=versionless&parent_id=1073992443&sequence=1
    http://database.ul.com/cgi-bin/XYV/...n=versionless&parent_id=1073992443&sequence=1

    Neither of them tells me what level those things are certified to. In
    comparison, google searches usually refer power supplies to UL-1950...
    there's no such code on those pages, the closest thing to a category
    code I can figure, is "QQGQ8"

    Another thing is, I seemed to have dug up a can of worms when looking
    at the info for this example. Some of the models are lumped together,
    like the True480 and True550 for the Antec, with one single set of
    ratings. The 480 and 550 model have different ratings according to
    Antec. Does this mean that the 480 is actually capable of outputing
    the same level as the 550?

    --
    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
     
  11. This is weird, I've seldom seen the forward UL symbol in most retail
    packed stuff here. Does that mean these things are actually NOT safe
    for consumers to use? Is that why some of them have wording about
    Professional Installation required? :p

    --
    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
     
  12. 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
    Probably some kind of CYA (not CSA) thing.

    Best regards,
    Spehro Pefhany
     
  13. I read in sci.electronics.design that The little lost angel <[email protected]
    overgirl.lrigrevol.moc.com> wrote (in <
    et.sg>) about 'Safety of electronic equipment?', on Fri, 12 Dec 2003:
    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.

    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.
     
  14. For CSA and the US equivalent (NEC Article 500, in this case),
    hazardous atmospheres are grouped: "Class XX", "Division NN" and
    "Group YY", where XX is a number in Roman numerals, NN is a number,
    and YY is a letter. No "Levels" involved, and no numbers greater than
    2 or III.

    Actually, it looks to me like he's talking about computer networking
    cable standards which are of tertiary interest to most of us.

    Best regards,
    Spehro Pefhany
     
  15. John Fields

    John Fields Guest

    ---
    Some of us do.

    I've done a couple of designs which were beat up by UL and passed, but
    I don't usually like to offer "advice" re. safety standards other than
    referring an enquirer to specific documentation if I can remember it.
    ---
     
  16. Active8

    Active8 Guest

    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.

    I wonder how that could affect some companies out there. I build my
    own boxes from components but I do have an old HP Vectra XU and
    it's got a UL logo on it. I've never bought a box cobbled together
    per my specss from a company.

    Mike
     
  17. When I apparently don't get a joke it is *always* intentional. ;-)
    FCC is probably at least as big an issue.

    Best regards,
    Spehro Pefhany
     
  18. Active8

    Active8 Guest

    No, my fault. I top posted and the hyphen in your sig causes news
    (& mail, IIRC) clents to not quote that part since the "who said
    what" is posted at the top.

    Before I go furthur, would someone please post the link to that
    site that converts long links to short ones for this girl? Those
    links below are a PITA and I can't find where I stashed the link
    right now.
    I'm not surprised. The current ansi/iso C++ standard is $750, but
    the working draft is online.

    Forget my PS example. I couldn't discern a specific question
    regarding that, anyway. Try what John said.

    As for designers not knowing much about safety standards... pay no
    attention to the man behind the curtain. I look up stuff that isn't
    burned in bio ROM so I don't fry anyone. I use stuff that's been
    known to work, and personally, I haven't had to deal with looking
    up the UL crap so far and rue the day when I do. It was bad enough
    sorting out the FCC crap so I'll probably consult with a cert lab
    for any future UL woes.

    <snip>


    BRs
    Mike
     
  19. Active8

    Active8 Guest

    I would think someone was exposed to it at least indirectly. It
    would have to be someone who designed connectors or boxes or was
    responsible for UL stuff in one way or another. Maybe someone
    responsible for writing the specs that get passed to the designer.
    Your statement is too broad. You said yourself that you've never
    heard of specific levels, so the whole question was hosed. Sales
    bs.

    See if you can find UL stuff in a NEC handbook or the EE bible. My
    relay's rated for 10A, it'll work. My traces will handle the
    current, blah, blah... My box manufacturer uses ABS plastic with UL
    flammability rating X. WTF do I care about the details of how he
    did the flammability test? Use a UL approved IEC connector with or
    without EMI filter and don't worry unless you need to get the
    assembly approved for sale to the public.

    Chances are, the people that look that crap up aren't good enough
    to be designers. Just like the idiots at the patent office that
    issue patents that can't be enforced or on crap products. If they
    were good enough to be designers, they wouldn't be pushing papers.

    Mike
     
  20. Active8

    Active8 Guest

    Don't I know it. I just never delved into UL and figure it's as
    convoluted a read as title 47, but I could be wrong. I hope I'm
    wrong.

    Mike
     
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