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service bonding 2011 NEC

Discussion in 'Electrical Codes' started by BSSTG, Jul 25, 2011.

  1. BSSTG

    BSSTG Gold Member

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    Greetings all,

    Well I'm confused with 250.92 (B).

    My question is this. Are grounding bushings or grounding locknuts required on service conduits under all circumstances in lieu of standard locknuts now? Or are the gounding bushings and locknuts only required around concentric knockouts, reducing washers and so forth? It looks to me as if standard locknuts are not allowed for bonding of service equipment under any circumstance but I'm not sure if I'm reading this right

    thanks

    BS
     
  2. Bryan Holland

    Bryan Holland Silver Member

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    Here's how I understand it.

    All the stuff in section 250.92(A)(1)&(2) are required to be bonded together. The method for bonding these items together can be any of the (4) methods indicated in section 250.92(B). Standard locknuts or bushings used by themselves can not be used to satisfy these requirements. In addition, bonding jumpers are required where the potential for an impaired connection is present due to inadequate connection beetwen an enclosure and a raceay fitting.

    The moral of the story is this. When in doubt, bond.
     
  3. raider1

    raider1 Silver Member

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    This change was just a re-wording of the requirements already contained in 250.92.

    Standard locknut can't be used for bonding on the line side of the service and bonding bushings or locknuts are required to bond metallic raceways on the line side of the service even if concentric, eccentric or reducing washers are encountered.

    Chris
     
  4. RJJ

    RJJ Platinum Member

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    Chris: By any chance do you have a photo of a proper install? This is a great question and I agree with Bryan on when in doubt!
     
  5. TimNY

    TimNY Platinum Member

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    Also, if we could have the section.. for those of use who don't have the 2011 NEC yet :) thanks!
     
  6. raider1

    raider1 Silver Member

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    Check out 250.92(B).

    Chris
     
  7. Francis Vineyard

    Francis Vineyard Sawhorse

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  8. RJJ

    RJJ Platinum Member

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    Francis: Good enough! This is a section often missed. Sometimes a picture goes along ways to allowing ones understanding od an issue. It also can stimilate more discussion on a subject that needs clear understanding.
     
  9. chris kennedy

    chris kennedy Sawhorse

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    This is how it reads.

     
  10. jar546

    jar546 *****istrator

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    So here is the question. If the service disconnect is a regular panelboard and the metal raceway entering the service panel comes through a concentric knockout, needs to be bonded with a bond bushing or bonding locknut, does that mean that all branch circuits and feeders that leave that same service panelboard must have the same bond bushings or bonding locknut if they are connected to a concentric KO with metal raceway?
    Food for thought..... :)
     
  11. Rick18071

    Rick18071 Sawhorse

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    2014 NEC Handbook says just the line side.

    upload_2019-9-17_14-18-45.png
     
  12. jar546

    jar546 *****istrator

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    Is there anyone out there that requires this at service panels that have EMT or other metallic conduit leaving on branch circuits and feeders?

    I do not for the record.
     

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