supplementary ground

[snjeza]

when supplementary ground is required?

 

[bphgravity]

Re: supplementary ground

Only when metal underground water pipe is used as a grounding electrode. See section 250.53(D)(2).

 

[volt101]

Re: supplementary ground

Supplemental Electrode Required...
Supplementary grounding electrodes not required but permitted...

Hmmmmmm....hung up on wording......

 

[steve66]

Re: supplementary ground

I agree with Bryan, but I would like to add that there are "supplemental electrodes" and there are "additional electrodes".

You will need an "additional electrode" if you are using a rod, pipe, or plate electrode that has a resistance to ground of 25 ohms or more. See 250.56.

So you could have the water pipe as the first electrode, a ground rod as the supplemental electrode, and second ground rod as the additional electrode.

Steve

 

[ryan_618]

Re: supplementary ground

I agree with Volt. 250.54

[ June 09, 2005, 05:49 PM: Message edited by: ryan_618 ]

 

[romeo]

Re: supplementary ground

I agree with Bryan. I believe the reason for the supplementary ground is to maintain a grounding electrode system in the event that the metal water pipe is changed to plastic.

romeo

 

[ryan_618]

Re: supplementary ground

Originally posted by romeo:
I agree with Bryan. I believe the reason for the supplementary ground is to maintain a grounding electrode system in the event that the metal water pipe is changed to plastic.

romeo

Thats the reason for a supplemental electrode, but not a supplementary electrode. Again, see 250.54

 

[tom baker]

Re: supplementary ground

I call the supplementary electrode a time and materials electrode. Its a ground rod you install on a slow day. Does not serve any purpose, but it you think it helps then install as many as you want.

 

[steve66]

Re: supplementary ground

So we have the "supplemental electrode" Bryan mentioned 250.53 and is sometimes required.

And the "supplementary electrode" in 250.54 is a completely different animal that is never required, but only permitted.

Add the "additional electrode" I mentioned, and could they make it any more confusing? This is like "grounded conductor", "grounding conductor", and "equipment grounding conductor", and "grounding electrode conductor" all over again

 

[shortcircuit2]

Re: supplementary ground

Supplementary Grounding Electrodes are used for tall metal light poles, metal poles for electric signs and sometimes for large machines...

shortcircuit2

 

[LarryFine]

Re: supplementary ground

Originally posted by steve66:
This is like "grounded conductor", "grounding conductor", and "equipment grounding conductor", and "grounding electrode conductor" all over again :roll:

 

[romeo]

Re: supplementary ground

Sometimes I read too fast. You are correct. Thanks for pointing that out ryan.

romeo

 

[ryan_618]

Re: supplementary ground

I understand Romeo, beleive me!

 

[mc5w]

Re: supplementary ground

If somebody is 100% dependent on ground rods or if the water utility sticks dielectric unions into water services to keep the main from acting as a grounding bus, then you do need as many electrodes as you can get.

Also, a local ground, preferably an equipotential mat, is required by the laws of physics if what you are doing is milking cows, running an induction furnace, or operating a high voltage switch. Cows do not like the Cow Voltmeter Method. I have been shocked by picking up a 1.5 volt D cell by the ends because I let too much in the way of perspiration salts build up on my hands.