Electrode grounding conductor

[don_resqcapt19]

Re: Electrode grounding conductor

Bob,
The ground covering has very little effect on the moisture level a few feet underground. I see no code issue with installing a ground rod under concrete or blacktop.
Don

 

[bob overfield]

Re: Electrode grounding conductor

Can someone explain to me why we have to use table 250-66 for the sizing of the conductor when we lay the conductor in the footing, and when we connect to a rebar we can use a #4.Is there somekind of deteration on the copper from the cincrete? Also why do we use table 250-66 for the conductor sizing on the building steel, water pipe and such when a #4 copper is good enough for the Ufer.

 

[bob overfield]

Re: Electrode grounding conductor

Don, The way I should have started my comments about the rods under the concrete is ---in my area it is not a good idea. We are very dry with a very low water table. I have seen as many as four rods installed in the dirt or so called lawn. I know that if you picked up a section of the concrete you would find moisture under it from condensation. But is that moisture there through all seasons and is it enough. So if possible we stay away from the ground rod under concrete because if dirt or lawn that is on a sprinlker isn't good enough I don't think concrete is going to help. But if you have a big area of concrete
then it's not practicable.

 

[dereckbc]

Re: Electrode grounding conductor

Originally posted by bob overfield:
Can someone explain to me why we have to use table 250-66 for the sizing of the conductor when we lay the conductor in the footing, and when we connect to a rebar we can use a #4.Is there somekind of deteration on the copper from the cincrete? Also why do we use table 250-66 for the conductor sizing on the building steel, water pipe and such when a #4 copper is good enough for the Ufer.

Not sure I have the definitive answer, but I believe it has to do with the possibility of contact with conductors. It would be difficult for rebar to come in contact with a live circuit conductors, whereas contact with building steel and water pipes is probable. But I could be all wet.