Pole light grounding

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Electron_Sam78

Electron_Sam78

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Palm Bay, FL
I've got a job where some parking lot pole lights have an external ground rod and conductor at each pole. The poles are mounted on a concrete base. The tops of the ground rods are exposed and the mowing service has cut and dislodged the conductors from some of the rods and the customer is asking me if the rods are necessary and do they need to be reconnected.

I'm not sure if they are necessary or not. The concrete base of the poles with the steel mounting bolts sticking out is essentially a ufer ground, correct? Wouldn't the bases be suffucient grounding means?
 
I agree. I see them speced many times, but it's usually a back east engineer doing it mostly for lightning. We won't see lightning out here twice a year. If the engineer is persistant I will usually let them drop a bare copper down into the footing and use that.
 
Make sure that a grounding conductor is installed with the circuit conductors. It may sound strange but some poles are installed without the grounding conductor. It's in violation of Art 250 but some designers thought that a ground rod was all that they needed to clear a fault.
 
SEO said:
Make sure that a grounding conductor is installed with the circuit conductors. It may sound strange but some poles are installed without the grounding conductor. It's in violation of Art 250 but some designers thought that a ground rod was all that they needed to clear a fault.
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Yes, you are correct.
 
SEO said:
Make sure that a grounding conductor is installed with the circuit conductors. It may sound strange but some poles are installed without the grounding conductor. It's in violation of Art 250 but some designers thought that a ground rod was all that they needed to clear a fault.
Click to expand...

I'll check that out just to be sure. Let's say there isn't a grounding conductor. What then? I still wouldn't need the rods since the pole base is likely a better ground than the rod anyway.

Also, can anyone think of a need for a ground rod at every pole? This is river bottom area with a lot of deep, sandy soil. Footings for houses are required to be a minimum of 42". I'm not sure about specs for grounding electrodes for services or anything since I haven't done any service installs in that area
 
Electron_Sam78 said:
I'll check that out just to be sure. Let's say there isn't a grounding conductor. What then? I still wouldn't need the rods since the pole base is likely a better ground than the rod anyway.

Also, can anyone think of a need for a ground rod at every pole? This is river bottom area with a lot of deep, sandy soil. Footings for houses are required to be a minimum of 42". I'm not sure about specs for grounding electrodes for services or anything since I haven't done any service installs in that area
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If there is not a grounding conductor run with the circuit conductors your going to have to install one. Read section 250.4(A)(5). You still don't need ground rods at the poles.
 
I agree that you don't need ground rods at these poles.

Consider, however, that _if_ these ground rods are present, then they must be bonded to other grounding electrodes present.

-Jon
 
winnie said:
I agree that you don't need ground rods at these poles.

Consider, however, that _if_ these ground rods are present, then they must be bonded to other grounding electrodes present.

-Jon
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These are considered auxilary electrodes and do not have to be connected to the other grounding electrodes. See 250.54.
I call these time and material electrodes.
 
tom baker said:
These are considered auxilary electrodes and do not have to be connected to the other grounding electrodes. See 250.54.
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I was under the impression hat auxiliary electrodes still had to be connected to the EGC, and thus bonded to the rest of the grounding electrode system, although with smaller bonding conductors than might otherwise apply.

-Jon
 
cowboyjwc said:
I agree. I see them speced many times, but it's usually a back east engineer doing it mostly for lightning. We won't see lightning out here twice a year. If the engineer is persistant I will usually let them drop a bare copper down into the footing and use that.
Click to expand...

Florida DOT design regs #17502 require 20' of 5/8 copper ground rods in addition to the rebar for roadway lighting poles.
 
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