Benefit of ground rod for light standard

[jar546]

I see no benefit. They are not required.

Why are they always installed or spec'd out?

Please discuss:

 

[raider1]

IMHO it is due to a lack of understanding of the purpose of a grounding electrode. Engineers have speced ground rods at light poles for a long time and they have gotten complaisant.

Chris

 

[mark handler]

http://www.mikeholt.com/technical.php?id=grounding/unformatted/metalpoles&type=u&title=Ground%20Rod%20at%20Metal%20Poles%20a%20Waste?%20(8-5-2K)

Mike Holt’s Comment: The previous question continues to bug me that people insist that a ground rod be driven at metal poles that support lighting fixtures. From the mouth of one of my members "A lot of ‘black magic, shaman dancing, urban legends, wild-eyed guesses, and whatever someone taught you years ago’ are repeated as gospel."

Let me make a few statements to try to clarify this issue:

1.The National Electrical Code does NOT require a ground rod at metal poles.

2.A ground rod at a pole will NOT clear a line-to-ground fault for systems that operate at less than 600 volts.

3.A ground rod at a pole will NOT reduces the touch potential from the metal pole to the earth from a line-to-ground fault.

4.A ground rod is NOT required at a metal light fixture pole by the Lightning Protection Institute http://www.lightning.org.

5.A ground rod is NOT required at a metal light fixture pole by the Lightning Protection Standard (NFPA 780) http://www.nfpa.org.

6.A ground rod at the metal pole does NOT reduce damage to the fixtures, lamps, and the pole wiring, because the lightning traveled through the equipment on the way to the earth.

7.A ground rod at a metal pole does NOT protect the concrete foundation that supports a metal pole from lightning damage. If there were true, then electric utilities would never use concrete poles to support overhead wiring.

8.A ground rod at the metal pole does NOT protect the circuit wiring and equipment in the building from lightning damage (open back door). If you want to protect the circuit wiring in the building, then surge protection should be installed on the circuit conductors that go outside to the metal poles.

 

[fatboy]

Hit the link at the top of Mark's post, read down past what Mark pasted in, and interesting discussion.

 

[RJJ]

Maybe I am wrong, but I was under the impression that only the service ground rod was required and with the code changes now a second!

I have seen this done on light standards a number of times and always just wonder. WHY! WHY!