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Thread: Section 110.14(A)

  1. #11
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    Feb 2003
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    Illinois
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    Re: Section 110.14(A)

    Ryan,
    My comment to UL is, "you can't have it both ways!". UL has classified breakers for use in panles in violation of the panel manufacturer's instructions. They are telling us that we must follow the manufacturer's instructions but that classified breakers can be used in violation of those insttructions!
    Don
    Don, Illinois
    "It is the first responsibility of every citizen to question authority." B Franklin

  2. #12
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    Feb 2003
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    Florida
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    Re: Section 110.14(A)

    Would it be out-of-line for an inspector to ask the installer if they have torqued the terminations per requirements? I have never had no or ever heard of an inspector even making this request. Maybe installers would be more inclined to torque terminations if the code makes it a specific requirement and inspectors make it an issue?
    Bryan P. Holland, MCP

  3. #13

    Re: Section 110.14(A)

    HI everyone-

    I've had a LA city inspector have me snug the terminals of a panel board, then do my final torque in his presence's.
    STEVE
    Electrical Project Manager for comm. co.
    LA. CA.

  4. #14
    Join Date
    May 2003
    Location
    Salt Lake City, Utah
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    5,319

    Re: Section 110.14(A)

    You know Don it's funny, I was arguing about this very thing...classified breakers and whether or not its a violation, when somebody showed me this link! As I stated before, I have always shared your thoughts on the subject and was absolutely blown away when I saw this from UL. I disagree with it wholeheartedly.
    Ryan Jackson, Salt Lake City
    Inspector, Instructor

  5. #15
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    Mission Viejo, CA
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    Re: Section 110.14(A)

    Manufacture's instructions are always a consideration in product liability issues. And UL can indeed have it both ways; they write the rules on how they are willing to certify a product's use.

    As an design engineer, I can only state that, if a product performs as it is certified and is installed as per that certification, it will perform safely in my design. I am usually qualified to say it is installed per the certification, but I am not qualified to say that it will perform properly. That is left to NRTLs or the manufactures, if necessary.

    Both over and under torquing are potentially dangerous. I have found over-torquing more common.

    I have never been an "official" AHJ, but I have never had a problem having my construction crews properly torque connections. Fairly early in a job I simply ask them what the torque requirements are. If they know, I ask them to show me how they did or intend to do it; if they don't know, I still ask the same question and essentially remind them of 110.3(B). Once we establish how it is to be done, I review enough to feel confident. It rarely takes more than a single inquiry and I've run jobs with literally millions of terminations.

    There are enough "free wheel" torque wrenches and screwdrivers out there that checking for over torque isn't that difficult.
    "Bob"
    Robert B. Alexander, P.E.
    "I know that you believe you understand what you think the NEC says, but I am not sure you realize that what you read is not what it means." (Corollary to Charlie's Rule)

  6. #16
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    Re: Section 110.14(A)

    Bob,
    There are enough "free wheel" torque wrenches and screwdrivers out there that checking for over torque isn't that difficult.
    Can you expand on that. It is my understanding that after the connection is torqued, the wire will "cold flow" and if you comeback at a later time and use the same torque wrench and setting that the set screw will turn producing more pressure against the conductor and result in an "over torque" condition.
    Don
    Don, Illinois
    "It is the first responsibility of every citizen to question authority." B Franklin

  7. #17
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    Oct 2003
    Location
    Southern California
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    1,789

    Re: Section 110.14(A)

    Originally posted by don_resqcapt19:
    Ryan,
    My comment to UL is, "you can't have it both ways!". UL has classified breakers for use in panles in violation of the panel manufacturer's instructions. They are telling us that we must follow the manufacturer's instructions but that classified breakers can be used in violation of those insttructions!
    Don
    The manufacturers want you to buy their breaker. I've heard their arguments when classifed breakers first came out. There were no facts, just predictions of doom and gloom if you used a classifed breaker in their panelboard.
    Now if someone has some evidence of a classifeied breake failing in a panelboard I'm all ears
    I'm an Inspector, what do I know?

  8. #18
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    Apr 2004
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    Re: Section 110.14(A)

    Don,

    It’s a good question. Remember I was speaking from the perspective of the initial installation. However NFPA 70B and several NEMA maintenance guides such as PB.1 speak to it from a subsequent maintenance standpoint and they still give essentially the same advice; i.e., torque the terminations/connections per manufacturer’s instructions.

    “Cold flow” is generally a result of over-torque, not a precursor to it. Aluminum is more prone to it than copper although both can experience it. Other factors such as heat cycling and whether the connection is designed to be self tensioning all play a part. Some methods and instructions are more forgiving than others. This is why I believe knowing the manufacturer’s instructions is critical.
    "Bob"
    Robert B. Alexander, P.E.
    "I know that you believe you understand what you think the NEC says, but I am not sure you realize that what you read is not what it means." (Corollary to Charlie's Rule)

  9. #19
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    Feb 2003
    Location
    Massachusetts
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    48,276

    Re: Section 110.14(A)

    A company I worked for provided a service of opening up gear and checking torques. We would go back each year and put the torque wrench to the gear.

    Each year the wire terminal rotated a bit to hit the specified torque. The conductors get to looking mighty flattened.

    I question the value of doing this more than once in a switch gears life span. The once would be to verify all connections where tightened in the first place. Once this is done leave it alone.

    The majority of electric gear is left alone and remains trouble free. IR testing seems like a better way to go.

    This is just my uneducated opinion arrived at strictly from my own observations. In other words I may be way off base.

  10. #20
    Join Date
    Feb 2003
    Location
    Indianapolis
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    6,102

    Re: Section 110.14(A)

    It is common for a manufacturer to say that they will void the warranty if you use another manufacturer's circuit breakers. However, there are some manufacturers that are fighting back. For instance Siemens has a listing of circuit breakers for Square D type QO and has a $10,000 warranty so you may use them with impunity (lower right hand corner of the 1st page).
    Charlie Eldridge, Indianapolis, Utility Power Guy
    Responses based on the 2011 NEC, unless stated otherwise.

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