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Thread: Missing Ground Wire - Large Commercial Lighting Project - Exterior / Industrial

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    Missing Ground Wire - Large Commercial Lighting Project - Exterior / Industrial

    Hi Everyone, we are working on a very large exterior lighting conversation at an industrial site. Replacing 400W + 1000W HID fixtures w/ new LEDs. The problem is, the existing 40FT+ poles don't have an existing ground wire. To add a ground to these poles would require a $1M+ infrastructure upgrade and would not be approved.

    Question: Is this a circumstance where the functioning/existing electrical infrastructure that does not have a ground wire can be 'grandfathered' in with the new LED lights or does it require a complete upgrade to the lighting system?

    Any specific NEC code you could point us to?

    Thanks!!

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    Quote Originally Posted by electroman1985 View Post
    Hi Everyone, we are working on a very large exterior lighting conversation at an industrial site. Replacing 400W + 1000W HID fixtures w/ new LEDs. The problem is, the existing 40FT+ poles don't have an existing ground wire. To add a ground to these poles would require a $1M+ infrastructure upgrade and would not be approved.

    Question: Is this a circumstance where the functioning/existing electrical infrastructure that does not have a ground wire can be 'grandfathered' in with the new LED lights or does it require a complete upgrade to the lighting system?

    Any specific NEC code you could point us to?

    Thanks!!
    See 250.32(B)(1) Exception

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    Quote Originally Posted by david luchini View Post
    See 250.32(B)(1) Exception
    Hi David, are you able to expand one this at all?

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    Basically the section and exception is saying that the neutral could be used as the EGC if the installation was legal when it was install. This mostly was for detached buildings but could apply to other type structures.

    As required by the section there could be no other conductive paths back to where the feeder or branch circuit originated.

    The scary part of this is the poles can be hot if there is no EGC. I was called to a building where a landscaper was shocked between a fence and a pole we found that three 30' poles measured 277V between the pole and the fence, luckily they were a little over 7' apart and I'm not sure how the landscaper touched both.

    Personally I'd be concerned about the liability down the road if something happened. IOW's I would recommend adding an EGC.

    Roger
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    Quote Originally Posted by roger View Post
    Basically the section and exception is saying that the neutral could be used as the EGC if the installation was legal when it was install. This mostly was for detached buildings but could apply to other type structures.

    As required by the section there could be no other conductive paths back to where the feeder or branch circuit originated.

    The scary part of this is the poles can be hot if there is no EGC. I was called to a building where a landscaper was shocked between a fence and a pole we found that three 30' poles measured 277V between the pole and the fence, luckily they were a little over 7' apart and I'm not sure how the landscaper touched both.

    Personally I'd be concerned about the liability down the road if something happened. IOW's I would recommend adding an EGC.

    Roger
    Thank you for your reply! These are wood poles with overhead wiring strung from pole to pole. Does that change anything?

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    Quote Originally Posted by electroman1985 View Post
    Thank you for your reply! These are wood poles with overhead wiring strung from pole to pole. Does that change anything?
    With that being the case see 250.110(1). IMO, you would not need to worry to much about there not being an EGC.

    Roger
    Moderator

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