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When is UL certification necessary?

Discussion in 'Embedded' started by Mike Turco, Jun 7, 2004.

  1. Mike Turco

    Mike Turco Guest

    I'm having a hard time figuring out exactly when its necessary to enlist the
    services of UL, when its might be a good idea, and when its just a waste of
    money. They are, what, a QC lab? Do they test products to UL standards,
    government standards, legal requirements, or what?

    If I create a product, say a board that runs on 5V, and that 5V comes from a
    UL listed wall transformer, does the product need testing? What if the power
    comes from a USB port? What if you just plug the damn thing into the wall
    and gets its power that way? Does it make a difference whether the product
    is slated for sales into industrial, commercial or consumer applications? Is
    there a repository of "UL Approved" circuits?

    If you call UL on the phone -- in my experience -- they won't tell you
    anything other than, "Send us the product and we'll take a look." Yah, take
    look at my arse. They are a for-profit business.

    Where does one start to look for safety and legal requirements for
    embedded-type stuff (excluding RF and medical)? Do you just pluck your way
    through the CFR and ASTM requirements?
    Mike Turco, Jun 7, 2004
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  2. When your customers or your lawyers require UL approvals for
    your products.
    Grant Edwards, Jun 7, 2004
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  3. Mike Turco

    Richard Guest

    UL is an optional certification. (Actually, I think their stance is
    that they're not a certification, just a testing lab that checks for
    appropriate compliance. "We didn't say it was safe, just that it met
    the applicable standards.")

    It's not "required" officially, though many organizations may require it
    (large companies, government, insurers, distributors). It's also
    expensive for a startup product. (IIRC, $8K+ for safety + RF emissions
    for US only)

    UL tests your product to meet applicable regulations (e.g., safety, FCC,
    etc.). This varies by product type, intended application, and target

    Yes on all counts, and each of these points change the testing
    IME, they can be very helpful, given the right questions / approach (see
    I started by calling UL. :) Seriously.

    I took the approach of:
    * We need guidance before engaging UL services (i.e., we intend to use
    UL for testing, but we're in the design phase right now; nothing can be
    sent for review)
    * To prevent a badly flawed design (and re-test fees), we need info on
    the relevant certs (also so we know what certs are being covered for our
    * This is a first-time product, and no experience with certification
    * Here's what the product is / does / market / application
    * Which UL certifications apply, and what regulatory requirements to
    they satisfy?
    * What will it cost, how long will it take, what's involved? (e.g., how
    many units will be tested to destruction?) What about additional

    I've learned several things as a result:
    * What it'll take to get UL, why I want it, and when I need it
    * We want to avoid classification as an office computing device because
    it triggers a load of mandatory expensive FCC tests.
    * Our first product qualifies as a lab device, which is an exemption
    category for FCC testing.
    * Use a UL / FCC / CE wall wart whenever possible, instead of
    integrating line power.

    It took several discussions and e-mails to fully qualify our device's
    categories, after which UL finalized what'd be involved. Expect it to
    take several days to get the details.

    Good luck! (and what king of device are you creating?)
    Richard, Jun 7, 2004
  4. Mike Turco

    Rick Merrill Guest

    It is necessary to get UL approval when you or the customer buys any
    kind of insurance. For example, if you insure yourself against
    product liability or your customer insures themselves against
    hurting their employees or their customers (if they are an OEM).
    If your product melts down on someone's lap, they can sue your
    customer who then sues you.

    Ask your customers the question. - RM
    Rick Merrill, Jun 7, 2004
  5. Mike Turco

    Juhan Leemet Guest

    You should probably plan/budget for a couple of trips, esp. if you
    haven't done it before and if you're trying for (something like) FCC Class
    B rating of (significant) computing gear. I took some gear from a
    subcontractor design shop (with their own Faraday cage test room, where
    they did pre-testing) to UL in Chicago for testing. We had a number of
    surprises: e.g. row of LEDs showing through a slot in the case: yep, wave
    guide/antenna, beaming out all kinds of harmonics of the internal clocks.
    This was a graphics computer about 10 years ago. Devices and designs are
    probably a lot better now, but keep in mind that every bit of wire is an
    antenna! Every cutout/gap is a wave guide. ...and so on...

    In their case, I think the client wanted the Class B mostly for "bragging
    rights" (and part of their marketing spiel?) because the actual
    installations were going to be industrial (cable TV head ends). We met
    Class A. However, it is true that TV people are sensitive about EMI, etc.

    BTW, I think the FCC stance is that if any gear causes excessive
    interference (above the FCC Class ratings, and someone complains), it is
    the operator's responsibility to remove/fix it. If you can show UL
    testing passed FCC compliance, you have a "get out of jail free card",
    and they'll likely look at other gear first. However, if your "sample"
    passed FCC tests, but your production is defective, you might still have a
    problem. If any of your customers incur extra costs like that, they
    might try to sue you, for supplying defective/deficient gear. Even if you
    have weasel words in your contracts, they might try "best practices" ploy.
    Juhan Leemet, Jun 17, 2004
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