Lenny

We are installing new electric service in a campground. Each site has a 50/30/20 amp metered pedistal, fed on 5 site loop with sweetbriar {4/0-4/0-2/0 alum} from a 200 amp disconnect. A seperate #2 alum bond is also run. Some professionals say a ground-rod is required for each pedistal, others say that would be unessary, even others say it would pose a safty hazzard.

What does the forum think?

*The 20 amp receptical is a GFCI, there are 4 disconnects per transformer, there are 2 ground rods at the disconnects bonded to the neutral

Thanks

Lenny

RIVETER

You said that you are running a # 2 bond...I assume that you mean a #2 GEC. Is that correct?

sparks134

I believe you still needa ground rod!

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RIVETER

I agree with you. The NEC is just the BARE minimum that you must do...Other efforts are even better.

user5941

If you are running an EGC to each pedestal and bonding all the pedestals then a ground rod at each pad is not needed or required.

RIVETER

I won't disagree with you on this. But remember, the NEC is the MINIMUM that you have to do.

user5941

what function would a ground rod at each pedestal preform?

Lenny

In florida a single ground rod usually doesnt make a low ohm connection. The one argument was that they all would work together. As far as saftey, I feel the bond is most important. My opinion is not to use ground rods.
The argument against them is a far fetched sernario described below:

Site A has a fault in unit & ground-rod is inoperable & bond to site B is broken. Site B has proper ground-rod. It is possible to touch RV's at same time, causing shock.

Again, a far fetched senario in my opinion.



Riveter, what is a GEC? if its the grounded conductor, no we are using a 2/0.
The #2 is the bonded ground

thanks

lenny

user5941

the code says you need a minimum of 25 ohm ground rod , you drive a rod at the pedestal and it is at 25 ohms now lets do some math 120 volts divided by 25 ohms gives you 4.8 amps so you have 4.8 amps on your ground rod tell me how this is going to clear a 20 amp breaker.

RIVETER

I will be honest with you. I did not read your whole post. I DO know that the Florida area does not have the best DIRT to find a consistant LOW ohmage to ground. I will say that the purpose of, and the ONLY, purpose of the GEC (Grounding Electrode Conductor), is for lightning strikes, or possible abberant voltages such as a higher voltage line falling on a lower voltage line. Or, it could be a primary to secondary short circuit on the service transformer.

Lenny

the 25 ohm requirement makes sense to me, it makes sure the gec is actually grounded. The electrician who wants rods only cares about one per site citing that they will all work togather. My thoughts are that if you dont get down to a 25 ohm resistance you have wasted your time with the rods. The NEC says that the earth shall not be considered the bonded ground, which tells me to leave the rods out.
I own the campground, but we have a licensed electrician on staff, so we do our own work under my guidence. He sites many things as being REQURIED BY LAW, but I am unable to find them in nec.

Also, wouldn't you consider the NEC to be quite better than the bare minimum?

thanks

lenny

RIVETER

No , I would not...The NEC is the BARE minimum. AND...There is a vast difference between GROUNDING and BONDING>

user5941

If you were being graded and all you did was just to code you would get a D

Lenny

I think I am correct in that a bond is simply an electrically conductive connection, while a ground is a connection to earth.

So, it is common to bond the ungrounded conductors, as in my loop feed. Saying that your bonding hot legs gets a lot of funny looks around here.

thanks

Lenny

william1978

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RIVETER

In your first paragraph, you are correct. In the second paragraph, I am not sure what you are saying.

wareagle

No where in the NEC does it say you need a minimum 25 ohm ground rod. I do agree with you math. Thats why you install an EGC.

Lenny

As soon as you say bond, everyone {at least around here} assumes ground. But Bond, Bonded or Bonding simply means "connected". Reading through the NEC thinking bond=ground horribly screws up interpritations.

amptech

Clearing a 20A breaker is not what a grounding electrode is for. Do you understand the purpose of installing a grounding electrode at each structure served?

amptech

Maintain potential.