Service changes

[infinity]

The code requires one rod to have a resistance of 25 ohms or less. If you cannot prove that you have the 25 ohms or less then you have to use two rods. Testing rods can be expensive and cumbersome. Usually the cheapest method is to pound in two rods and you're done regardless of the resistance of the two rods. A CEE supplementing a water pipe is all that required, rods would not be needed.

 

[bgeorge]

You took the words right out of my mouth. We have been doing 2 rods for some time now.

 

[220/221]

In our area, it is required to install 2 ground rods and hit the main water line

In our area we try NOT to hit the water line.

 

[vinster888]

i personally think the ufer is not as effective as it could / should be. big plastic sheet between the earth and all.

 

[infinity]

i personally think the ufer is not as effective as it could / should be. big plastic sheet between the earth and all.

If the concrete is not in direct contact with the earth the use of 20' of rebar/#4 CU in the footing would not qualify as a CEE.

 

[Dennis Alwon]

If the concrete is not in direct contact with the earth the use of 20' of rebar/#4 CU in the footing would not qualify as a CEE.

If the sides of the footing are in contact with the earth then why would this not satisfy the wording of the code. This question was asked in Raleigh and a CMP member answered as you did but I did see the wording to support it. 250.52(A)(3) only requires the footing to be in contact with the earth. The sides of the footing are in direct contact.

I have mixed feelings on this one but would avoid the plastic.

 

[gndrod]

Stemwall Footing & Footers

Stemwall Footing & Footers

If the sides of the footing are in contact with the earth then why would this not satisfy the wording of the code. This question was asked in Raleigh and a CMP member answered as you did but I did see the wording to support it. 250.52(A)(3) only requires the footing to be in contact with the earth. The sides of the footing are in direct contact.

I have mixed feelings on this one but would avoid the plastic.

Hi Dennis,

Residential IRC R403 and R406 will agree with your comments. There are probably some localities that are over high water table areas vary from the foundation installation codes. Compliance to foundation footings and footers shall be supported [R403.1] on undisturbed natural soils or engineered fill. The reason why the sides (of the stemwall) are not in contact with soil is that they are required to be insulated and damproofed as part of the heat loss and moisture infiltration codes.

The IRC states that poly film to extend down to the top of the footer and not overlap or extend into the gravel or crushed stone footing. [R406.3.2] A turned down slab also has the same requirement with exception of the inside crushed rock with membrane support for the interior slab floor can roll over the crushed fill where the interior pour does not see soil. Also footer pours require the rebars to be 3" encased along the hard pan, so any UFER tie-in will be well below the parged masonry or poured stemwall damped sealing. That is where the stub ups must be wire bond attached. I hope this helps. I cover this in my latest book. rbj

 

[roger3829]

In our area we try NOT to hit the water line.

I always try to miss the water line too.

But when the rod hits a rock and takes off on a 45 degree angle....... you get to call the water company......

 

[gndrod]

1 or 2

1 or 2

Cold water (if metal) and 1 ground rod here in Northern California, accept San Francisco, where they want 2 ground rods no matter what

Hi electricguy61,

Has CA adopted the 2005 or 2008 NEC? Last time I was in Sacto area the CA 2004 was being enforced. I know from past work there are a few Counties that require 2 driven without test. rbj

 

[daleuger]

Art. 250.56 is what you need.

Ok so it's not required out right there's that 25 ohm rule. Might as well throw in 2 to be cautious. The helper's good for it.

 

[daleuger]

On a residential service change, I do a cold water ground and drive a single ground rod. It's my understanding that 250.56 refers to "A single electrode" consisting of a rod.... Since I have 2 electrodes, I only install one ground rod. I have done hundreds of service changes like this and never been corrected by an inspector.

In fact, I have never ever seen 2 ground rods installed on a service.....

That's what I was thinking and what I'd always done. I wasn't complaining about driving 2 rods. I was just wondering. Hey, it couldn't HURT anything to drive 2, right?

 

[Dennis Alwon]

On a residential service change, I do a cold water ground and drive a single ground rod. It's my understanding that 250.56 refers to "A single electrode" consisting of a rod.... Since I have 2 electrodes, I only install one ground rod. I have done hundreds of service changes like this and never been corrected by an inspector.

In fact, I have never ever seen 2 ground rods installed on a service.....

A single ground rod is required to supplement the cold water pipe as long as it has 25 ohms to ground. If you cannot achieve 25 ohms then one other rod is necessary and you are good to go. Because your area does not enforce this, our area didn't either until a few years ago, it doesn't mean it is NEC compliant. You can do thousands of these install and it won't necessarily be correct unless there is an amendment to this article or your area does get 25 ohms with one rod.

 

[waltinjc]

I'm new to this forum and I'm not really sure where to post this question and here seemed the likely place. I need to do a service change on my own home and I would like to move the panel to different location in my basement. I understand that I need to have a disconnect at point of entry, but does that disconnect need to be a lever type or can I use a small breaker enclosure with a 200 amp breaker in it?