underground PVC Conduit Grounding

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steve1234

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With traffic signal systems that have steel traffic signal posts indivually grounded at the poles and PVC conduit between the poles is there a benifit to providing a #6 conductor through the conduit along with the signal wires to electriaclly connect the pole grounds?
 
Yes,

You must provide a fault current path for current to return to the source. If this installation is under the NEC then take a look at 250.4(A)(5).

Chris
 
steve1234 said:
With traffic signal systems that have steel traffic signal posts indivually grounded at the poles and PVC conduit between the poles is there a benifit to providing a #6 conductor through the conduit along with the signal wires to electriaclly connect the pole grounds?
Click to expand...

Do you mean grounded as in a ground rod?
If so, the ground rod will never clear a line to pole fault. At 25 ohms resistance, with 120V, only 4.8 amps will be returned back to the supply. The circuit breaker or fuse will never open.

The NEC requires those poles to have an equipment grounding conductor per 250.118, sized per 250.122 to meet 250.4(A)(5).

Its critical you understand this. Some can recieve a fatal electrical shock, its happened.

The attached graphic from Mike Holt is based on a true incident in the State of Illinois. I had an article in the IMSA Journal some years ago about this subject.

Tom Baker
IMSA Level II TS Tech, IMSA Journal Author and Master Electrican
 
tom baker said:
Do you mean grounded as in a ground rod?
If so, the ground rod will never clear a line to pole fault. At 25 ohms resistance, with 120V, only 4.8 amps will be returned back to the supply. The circuit breaker or fuse will never open.

The NEC requires those poles to have an equipment grounding conductor per 250.118, sized per 250.122 to meet 250.4(A)(5).

Its critical you understand this. Some can recieve a fatal electrical shock, its happened.

The attached graphic from Mike Holt is based on a true incident in the State of Illinois. I had an article in the IMSA Journal some years ago about this subject.

Tom Baker
IMSA Level II TS Tech, IMSA Journal Author and Master Electrican
Click to expand...

I'm on board with Tom!!
 
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