ufer grounds

[jersey]

Is a #4 ufer ground the biggest wire you need if the service is 800 amps.Also the ufer ground was forgotten in the first deck of this new building, can the ufer be put in the second floor deck instead.I could not find anywhere that it said it has to be on the first floor.The ground would just be coming out of the ceiling instead of the floor.thanks

 

[dereckbc]

Re: ufer grounds

Refer to 250.52(A)(3). A number 4 AWG is the smallest gauge you can use for a ufer regardless of the size of the service. You are permitted to use larger if you want to.

The concrete footing used for the ufer must be in direct contact with the earth. So no the second floor will not work.

 

[jersey]

Re: ufer grounds

thanks for your reply. I also wanted to know if the #4 was adeguate for a 800 amp service. I cant find a sizing chart so i figuered #4 was the biggest you needed for any size service

 

[dereckbc]

Re: ufer grounds

Number 4 AWG is the smallest you can use on any ufer system regardless of the service size. There is no restriction to how large it can be.

 

[poolsparky]

Re: ufer grounds

hi jersey, you're right. #4 is also the largest required. 2002 code, 250.66 (B). I'm curious, are you laying 20 feet of the #4 in the concrete or bonding to the rebar?

 

[don_resqcapt19]

Re: ufer grounds

Jersy,

I could not find anywhere that it said it has to be on the first floor.

The code very clearly requires that a concrete encased electrode be in the bottom of a footing or foundiation that has direct contact with the earth. You cannot use the rebar or a copper conductor in a floor slab to make a concrete encased electrode.

Concrete-Encased Electrode. An electrode encased by at least 50 mm (2 in.) of concrete, located within and near the bottom of a concrete foundation or footing that is in direct contact with the earth, ...

Don