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  1. #1
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    Default "doubletap" neut/grd bar

    It is now required by code to have separate hole for each neutral wire.
    Older codes did not explicitly forbid this, "double taps" were only allowed if manufacturer specifically had UL test and said was ok.

    How likely was CH 200amp MBP sold in the late '70's-early 80's to allow "double taps" on neutral bar?

    Asking for a friend, please forgive vague question and poor communication skills.

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  2. #2
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    Default Re: "doubletap" neut/grd bar

    Quote Originally Posted by Dave Ruth View Post
    It is now required by code to have separate hole for each neutral wire.
    Older codes did not explicitly forbid this, "double taps" were only allowed if manufacturer specifically had UL test and said was ok. How likely was CH 200amp MBP sold in the late '70's-early 80's to allow "double taps" on neutral bar? Asking for a friend, please forgive vague question and poor communication skills.
    Right. The problem is that, to the best of my knowledge, no manufacturer expressly said that double-tapping neutrals was acceptable. Therefore, it is not.

    The wording by manufacturers typically allowed unused neutral terminals to be used for multiple equipment grounding conductors. However, this was commonly misinterpreted by electricians and inspectors for many years as allowed to attach multiple neutral (grounded) conductors.

    Take a look at a label in a service equipment from prior to the NEC clarification (I think 2002 NEC).

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  3. #3
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    Default Re: "doubletap" neut/grd bar

    Basically it all comes down to the wording.

    Installing more than one neutral conductor in a terminal is not allowed (versus 'being a code violation').

    The difference?

    Years ago, the labeling did not address how many neutral conductors could be installed in a terminal, but that of and by itself did not mean, or indicate in any way, that ONLY one neutral conductor was allowed in a terminal. That is because while the label did not say 'not more than one', the label also did not say 'only one', therefore it was not a "code violation" as the label did not address it.

    However ... the listing information in the applicable standards that panels were tested and listed to, did address that only one neutral was tested in per terminal, and that was therefore part of the 'listing information'.

    And we all know that 110.3(B) says that listed and labeled equipment shall be installed and used in accordance with its listing and labeling ... and 'more than one neutral in a terminal' created an installation which was "not in accordance with its listing and labeling" ... correct?

    And THAT was a violation of the code ... not that there was a code section which stated 'not more than one neutral conductor in a terminal', but because that the installation was now "not in accordance with it listing and labeling" ... which is a code violation in and of itself.

    Use the wrong screws for the cover? Sometimes it matters, in fact, many times it matters. Code violation for using the wrong screws for the cover? No, but ... it could result in the installation "not being in accordance with its listing and labeling" ... 110.3(B) code violation.

    Wording matters in the end result.

    Jerry Peck
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  4. #4
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    Default Re: "doubletap" neut/grd bar

    Thanks Jerry and Gunnar, exactly what I was looking for


  5. #5
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    Default Re: "doubletap" neut/grd bar

    I call it double lugging on the ground/neutral bus bars and double taps when it is done on the breakers.

    Definitely call out doubling of neutrals on the bus bars. Had a past client that began experiencing a problem with tripping of breakers shortly after moving in. They called an electrician who looked at their panel and and cited multiple "double taps" in the panel and called it a safety/fire hazard (no double taps on the breakers.....only on the bus bars). I had to take the hit as I did not call out what I refer to as double lugging and the client was now convinced by the electrician I placed their family at risk.

    It was an expensive learning experience as I offered to pay for the subpanel the electrician installed.

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  6. #6
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    Default Re: "doubletap" neut/grd bar

    Just as a wording change, I referred to either (at breakers and/or neutral bus terminal bars) as multiple tapping - I found enough 'more than one' tapped terminals (many with three, even four conductors) that I just used "multiple".

    Keep in mind that older electrical panels typically had labels which did not state that two 'ground conductors' were allowed.

    I suspect that the change to allowing two ground conductors in one terminal happened around the same time as the labels began stating 'one' neutral conductor.

    And I recall having seen some which included 'one neutral' conductor, and still only 'one' ground' conductor. The change to 'two' grounds in a terminal did not occur considently across the board at the same time.

    So don't "assume" two grounds are okay, read the labels.

    Jerry Peck
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    www.AskCodeMan.com

  7. #7
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    Default Re: "doubletap" neut/grd bar

    When I see this and write up the disapproval for such installation I prefer to use the proper and correct wording.
    More than one ( 1) grounded ( neutral) conductor installed in a terminal ,where only one(1) conductor is allowed by the NEC.
    Just saying ??..


  8. #8
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    Default Re: "doubletap" neut/grd bar

    Quote Originally Posted by jack davenport View Post
    When I see this and write up the disapproval for such installation I prefer to use the proper and correct wording.
    More than one ( 1) grounded ( neutral) conductor installed in a terminal ,where only one(1) conductor is allowed by the NEC.
    Just saying ??..
    That brings this question: is the grounded conductor a "neutral", or is it just a "grounded conductor"?

    The "grounded conductor" on a 120 volt circuit is not a "neutral" ... even though it is most often referred to as 'the "neutral" conductor', it is not a "neutral", it is just a current carrying conductor the same as the "ungrounded" conductor is.

    And if common terminology is suitable for part of the description, then common terminology should be acceptable for the full description.

    Correct??

    Jerry Peck
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    www.AskCodeMan.com

  9. #9
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    Default Re: "doubletap" neut/grd bar

    Ouch, Nick, too bad with today's legal system it costs less and does less damage to your goodwill rep to just pay up and move on.

    John Kogel, RHI, BC HI Lic #47455
    www.allsafehome.ca

  10. #10
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    Default Re: "doubletap" neut/grd bar

    Quote Originally Posted by John Kogel View Post
    Ouch, Nick, too bad with today's legal system it costs less and does less damage to your goodwill rep to just pay up and move on.
    Agreed John. It was a no-win situation.

    "It takes a big man to cry. It takes an even bigger man to laugh at that man". - Jack Handey

  11. #11
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    Default Re: "doubletap" neut/grd bar

    Quote Originally Posted by Jerry Peck View Post
    That brings this question: is the grounded conductor a "neutral", or is it just a "grounded conductor"?
    The "grounded conductor" on a 120 volt circuit is not a "neutral" ... even though it is most often referred to as 'the "neutral" conductor', it is not a "neutral", it is just a current carrying conductor the same as the "ungrounded" conductor is.
    And if common terminology is suitable for part of the description, then common terminology should be acceptable for the full description.
    Correct??
    Jerry,

    I think it is not correct, at least according to my (emu brained) interpretation of these three definitions from the 2016 California Electric Code (based on the 2014 NEC model code):

    Neutral Conductor. The conductor connected to the neutral point of a system that is intended to carry current under normal conditions.


    Neutral Point. The common point on a wye-connection in a polyphase system or midpoint on a single-phase, 3-wire system, or midpoint of a single-phase portion of a 3-phase delta system, or a midpoint of a 3-wire, direct current system.
    Informational Note: At the neutral point of the system, the vectorial sum of the nominal voltages from all other phases within the system that utilize the neutral, with respect to the neutral point, is zero potential.


    Grounded Conductor. A system or circuit conductor that is intentionally grounded.

    My version of the code states that the "neutral conductor" carries amperage. I believe the gobbledegook in the "informational note" of "neutral point states" that neutral is zero volts, but it is clearly more complicated than that. The definition of the "grounded conductor" is intentionally grounded, but does not specifically state that it carries amperage.

    In a 240/120 volt, single-phase residential system, we have three entrance conductors. Two are ungrounded and one is grounded. But, this grounded conductor carries amperage and is connected to the midoint on the single-phase, three-wire system.

    Therefore, neutral and grounded, in residential construction, are synonymous.

    Ok Jerry, go to town and tear apart my flawless reasoning! Time for me to head out to my inspection.

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  12. #12
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    Default Re: "doubletap" neut/grd bar

    Gunnar,

    In Miami for the week and don't have my codes.

    I'll have to look up the definitions when I get back. I do now recall some code wording changes in various sections due to changes in the definition of neutral conductor.

    Jerry Peck
    Construction Litigation Consultant ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  13. #13
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    Default Re: "doubletap" neut/grd bar

    Oh man! You mean I have to wait? Geeze!

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