UFER ground question

[olly]

I feel like an idiot for having to ask this question that I should know. Residential 200A service, concrete foundation, a piece of rebar is stubbed out to make the UFER ground connection. I would need to run #4 copper per table 250.66 correct? Also will your normal "acorn" or ground rod connector work to connect the wire to the rebar? I'm pretty sure code still requires two ground rods 6' apart, but do you really need it if you have a UFER ground?

 

[jumper]

I feel like an idiot for having to ask this question that I should know. Residential 200A service, concrete foundation, a piece of rebar is stubbed out to make the UFER ground connection. I would need to run #4 copper per table 250.66 correct? Also will your normal "acorn" or ground rod connector work to connect the wire to the rebar? I'm pretty sure code still requires two ground rods 6' apart, but do you really need it if you have a UFER ground?

#4 CU-Yes.

Standard acorn - I believe not. They have listed clamps for rebar.

Rods not needed if you have UFER.

 

[FionaZuppa]

ufer, another interesting topic. pros & cons, hopefully you dont run into the cons.

A disadvantage of Ufer grounds is that the moisture in the concrete can flash into steam during a lightning strike or similar high energy fault condition. This can crack the surrounding concrete and damage the building foundation

i guess you could help mitigate this unlikely event by adding and bonding a 10ft earth rod?

 

[jaggedben]

The GEC does not need to be a #4 if the service conductor size doesn't require it according to table 250.66. #4 is just the max that can be required for a UFER. Good idea to run it though, just in case someone decides to upgrade the service in the future.

 

[jumper]

The GEC does not need to be a #4 if the service conductor size doesn't require it according to table 250.66. #4 is just the max that can be required for a UFER. Good idea to run it though, just in case someone decides to upgrade the service in the future.

Op has a 200A service, so he has to run a #4.

 

[petersonra]

The GEC does not need to be a #4 if the service conductor size doesn't require it according to table 250.66. #4 is just the max that can be required for a UFER. Good idea to run it though, just in case someone decides to upgrade the service in the future.

plus it is not required to have any extra physical protection.

 

[infinity]

ufer, another interesting topic. pros & cons, hopefully you dont run into the cons.



i guess you could help mitigate this unlikely event by adding and bonding a 10ft earth rod?

If the CEE exists you are required to use it. If not then use 2 ground rods if you're worried about the unlikely event that you've mentioned.

 

[kwired]

ufer, another interesting topic. pros & cons, hopefully you dont run into the cons.



i guess you could help mitigate this unlikely event by adding and bonding a 10ft earth rod?

I'd bet a significant amount of current still finds it's way to the CEE and possibly still results in similar damage - but this has to be nearly direct hit as well - chances are there is a lot of other damage.