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UL approval

Discussion in 'Electronic Basics' started by Keith Rathband, Sep 5, 2005.

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  1. I'm designing a smart home system, which will need to be UL approved. I
    never gone through this before, and have some questions.

    What does this involve ?

    What are the lilkley costs ?

    What considerations should i make in my design ?

    What aspects will UL be mainly concerned with, ie, RF emmisions, High
    voltage saftey etc ?


  2. ryan weihl

    ryan weihl Guest

    buy equipment that is UL approved.
    If you want to design it yourself you are looking
    at several $1000 to cover the cost of the approval
  3. Chris

    Chris Guest

    Hi, Keith. UL doesn't "approve" anything anymore. You can obtain UL
    listing, which means your product can carry the UL certification label.
    It shows that samples of the product have been tested by UL and been
    found to conform to the applicable standards (available, of course,
    from UL).

    Without knowing more about your product, it's not possible to say which
    standards you must test.

    You might want to go explore the UL website. They do have quite a bit
    of non-technical information about their standards, which will give you
    an idea where you want to go.

    But UL listing isn't cheap, and it's an impossible project for a
    newbie. If your product is worth it, and UL listing is essential, you
    should hire an engineer with some experience in the applicable
    standards and the UL submittal process as a consultant. He can help to
    guide your product through certification.

    Good luck
  4. Dan Hollands

    Dan Hollands Guest

    Chris's suggestions are good but to more specifically answer your questions

    UL is concerned with Safety - they have many different specifications
    targeted at different products. For electronics safety related to the
    primary power and to fire are the main considerations. Your design should us
    UL listed components for anything connected to the mains powers e.g.
    transformers, filter capacitor, terminal blocks, relays etc. You also have
    to pay attention to trace spacing on the pcb and the pcbs must be of
    flameproof material. Grounding, wire insulation and terminal spacing are
    also issues. In addition to submitting a unit and documents, UL will
    periodically inspect your manufacturing facility to insure that the product
    being manufactured matches the unit they inspected.

    RF emissions requirements are governed by the FCC they require testing of
    any consumer electronic

    Although the US doesn't have any requirement for electrical noise immunity,
    if I was designing a smart home system I would want design tested to the EU
    standards (CE) for impulse and RF noise withstand capability so the
    electrical noise would not mess up the operation and make it dumb house

    If you are not designing hardware from scratch but are putting together a
    system from commercially available components, then I would make sure the
    units are UL, FCC and CE certified.


    Dan Hollands
    1120 S Creek Dr
    Webster NY 14580
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