Street Lighting supplied by the utility company

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Kessler4130

Senior Member
Location
Maryland
Good evening gentlemen,

My questions is regarding the grounding of lighting fixtures outdoors supplied by utility company power. I understand that the NEC does not apply to most utility installations, but let me fill you in on what is going on.

We installed some light fixtures on wooden utility poles in the District of Columbia, in place of existing fixtures. The utility is not supplying us with a neutral and a ground, just one bare conductor connected to XO on the transformer, and both our neutral and fixture casing/arm ground are connected to that, as it was originally.

The inspector is making us remove the ground wire from the bare XO conductor, run a bare wire down the pole, and drive a ground rod instead. Now to me this seems to defeat the purpose as I would think the fixture casing could remain energized as would the ground around the ground rod if there was a ground fault. I don't see how this installation serves anything but his ego. Please correct me if I am wrong.

Thank you for your time.
 

Kessler4130

Senior Member
Location
Maryland
Ok let me clarify a few thinks I did not mention.

The inspector is a DDOT inspector, any project in public space are over seen by DDOT.

The installation in question is not a wood pole fixture, but 2 cast iron poles, which have ground rods in the foundations, and are both fed from the same POCO wood pole. However the ground will now go from the poles to thier individual ground rods, and then to another ground rod at the wood pole and will be removed from the bare conductor connected to XO on the transformer.

So our only electrical connection from the poles, and fixtures will be through the dirt.
 

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
He is having you create a very dangerous condition, if there is a fault from one of the hots to the pole, it will most likely not trip the overcurrent protection, plus make the pole live to anything that is properly bonded.
 

iMuse97

Senior Member
Location
Chicagoland
You have a problem. The DDOT inspector needs to talk with their engineers. Meanwhile, don't do what he's required. You're the one putting it on the line.
 
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Kessler4130

Senior Member
Location
Maryland
You have a problem. The DDOT inspector needs to talk with their engineers. Meanwhile, don't do what he's required. You're the one putting it on the line.
Yes sir, I have a crew heading there today, and they have been instructed to ignore that punch list item. I will speak with him and see where his justification is coming from.
 

iwire

Moderator
Staff member
Location
Massachusetts
He is having you create a very dangerous condition, if there is a fault from one of the hots to the pole, it will most likely not trip the overcurrent protection, plus make the pole live to anything that is properly bonded.

You have a problem. The DDOT inspector needs to talk with their engineers. Meanwhile, don't do what he's required. You're the one putting it on the line.

I agree with these two guys 100%.

Don't do it.

Also remind the inspector that bare conductor is called an MGN (Multi Grounded Neutral) it can and should be used for grounding objects such as your light.
 

Kessler4130

Senior Member
Location
Maryland
I agree with these two guys 100%.

Don't do it.

Also remind the inspector that bare conductor is called an MGN (Multi Grounded Neutral) it can and should be used for grounding objects such as your light.

Thank you I will, and I did verify with my co-workers today that he is making them do this on any wood pole that does not already have a ground rod and bare conductor running vertically up the pole.

So unless there is a existing ground that is already in place, the fixtures, fixture arms, and casing are grounded only by the ground rod.

Thank you for all your support in this ordeal.
 

Kessler4130

Senior Member
Location
Maryland
To keep you updated, I had a crew drive a ground rod at the pole with no utilization equipment only because I was not on site as I was tending to an emergency and another was there in my place, otherwise I would have simply said no, I will do it on a change order as it is outside my scope of work and not required by any national or local jurisdiction.

They connected the egc from the poles to the new ground rod, and did not touch the connection to the POCO multi grounded neutral, I meet the inspector this morning for a walk through and will update you on his next bit of amazing wisdom, but just to give you something to chew on heres one from a while back.

" you cannot splice in T- Bases. "
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
How high above the ground are the fixtures? 250.110 may permit the installation of the fixture without an equipment grounding connection.
 
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