Grounding Electrode For a Service on a Bridge

[Sthome25]

I have an odd situation. I will be updating a service that is located in the center of a steel bridge. The service (60 Amp) is for street lights and eventually some cameras. The AHJ (PennDOT) typically requires (2) 8' ground rods, but that doesnt work in the middle of a bridge. I am thinking that I can put a lug to the steel framing of the bridge at the service and at the end of the bridge, then set the two rods on the side of the bridge where the service is fed from (pole mounted transfromer). Any other insight on this situation would be greatly appreciated.

PA is currently using the 2014 NEC.

 

[LarryFine]

Welcome to the forum.

I would counter that you have a great Ufer grounding electrode, and you should only need to bond to the bridge itself.

 

[Greentagger]

Sounds reasonable. Refer to 250.68(B) & (C)(2). Seems as though a GES would have been on the engineered drawings.

 

[Sthome25]

Sounds reasonable. Refer to 250.68(B) & (C)(2). Seems as though a GES would have been on the engineered drawings

250.68(C)(2) should satisfy my PennDOT inspector. Thank you for the reference, I overlooked that paragraph. The engineered drawings I get are not that good. I get a line showing an electrode and note indicating 2 ground rods. Thanks for the help!

 

[LarryFine]

Why would a bridge foundation require rods? Why wouldn't bonding to the bridge alone be adequate?

 

[macmikeman]

Since as you say, you are out on the middle of a bridge, in my humble opinion you should toss out two anchors, at least six feet apart, one on each side of the bridge and land the chains into the ground bus on the main disconnect panel.

 

[102 Inspector]

Would they have to be 8 foot anchors and how do you guarantee they are in direct contact? I agree, the UFER is already provided and bonding only additional.

 

[hillbilly1]

250.68(C)(2) should satisfy my PennDOT inspector. Thank you for the reference, I overlooked that paragraph. The engineered drawings I get are not that good. I get a line showing an electrode and note indicating 2 ground rods. Thanks for the help!

That’s because the engineer was lazy! LOL!

 

[Sthome25]

Ground rods are required by AHJ (90.4). Its a PennDOT requirement for services.