Upgrade to UFER grounding

[102 Inspector]

Existing home is adding an addition with basement and can provide a concrete encased electrode in the foundation system. Existing electrical service was upgraded about 5 years ago and is grounded via 2 ground rods. Existing service is about 15 feet from new concrete encased electrode exposed through foundation wall. Would they be required to now connect to the UFER ground or is it optional. There will be no other changes to the service, only branch circuit interior with the adddition. Are there any benefits to changing to grounding electrode system to UFER with no other changes. Kind of strandling the fence on what to tell the electrician to do with this situation, any comments?

 

[kwired]

NEC does not make a clear distinction in this case. Some AHJ's may want you to use this CEE, others may not care, but it isn't wrong to do so either.

The CEE is likely going to be less resistance than the ground rods ever will be, If I get the opportunity to use an added CEE where there presently is not one being used, I usually do so.

 

[bullheimer]

id be optional. but i say the more the merrier, but would like to know how the ufer is less resistance than the two ground rods. seriously, i don't know and would like to. i have never really bought into this whole "cement is a conductor" philosophy. wet cement, sure. dry cement...not so much.

 

[jumper]

id be optional. but i say the more the merrier, but would like to know how the ufer is less resistance than the two ground rods. seriously, i don't know and would like to. i have never really bought into this whole "cement is a conductor" philosophy. wet cement, sure. dry cement...not so much.

Here is one link on the subject.

http://www.psihq.com/iread/ufergrnd.htm

 

[ActionDave]

i have never really bought into this whole "cement is a conductor" philosophy. wet cement, sure. dry cement...not so much.

Concrete buried underground is rarely ever dry.

 

[augie47]

I agree with the others that using the Ufer would be a good plan and I think 250.50 supports your requiring it.

 

[kwired]

id be optional. but i say the more the merrier, but would like to know how the ufer is less resistance than the two ground rods. seriously, i don't know and would like to. i have never really bought into this whole "cement is a conductor" philosophy. wet cement, sure. dry cement...not so much.

How about you go in a basement or garage and stand barefoot on the concrete floor and with a bare hand grab a live 120 volt to ground conductor and tell us if the concrete conducts any electricity?

It will likely not conduct well enough to operate much of any useful loads to you, but does conduct well enough to discharge energy to earth, which is the primary reason for grounding electrode use, it will have a lower resistance in most cases than a ground rod simply because there is so much more surface contact with the earth.

Concrete buried underground is rarely ever dry.

Which is why the CEE is supposed to be in the building footer/foundation and not just any concrete component.

 

[Dennis Alwon]

If you are not doing work on the service I am not sure you can be required ti use the CEE, IMO, I would not hesitate to use it but I still don't think I am required to do so.

 

[bullheimer]

How about you go in a basement or garage and stand barefoot on the concrete floor and with a bare hand grab a live 120 volt to ground conductor and tell us if the concrete conducts any electricity?

Okay! Be right back!