Extending UFER Ground

[djr3203]

I have a project where there is no ground bar in the existing electrical room and the grounding electrode from the UFER ground and water pipe was run directly to the ground bar in the main switchboard. We are redoing the electrical infrastructure and the main switchboard is being demolished and a new one is being placed in an adjacent room. We need to somehow extend the UFER ground and reconnect it to the new ground bar we are installing in the room. I am assuming the UFER ground comes up from the concrete and up into the existing switchboard. I am also assuming there is not enough conductor to extend it to the new ground bar.

1. Is it possible to splice a new ground conductor to the UFER ground to extend it to the ground bar? Will this increase the resistance to ground?
2. Are there any codes that prohibit splicing to the UFER ground to extend?

I am thinking we can splice a new conductor to the UFER, saw cut a section of the concrete floor, and extend the UFER to the wall where it can then come up and be connected to the ground bar.

Thanks in advance for the thoughts/comments.

DJR

 

[djr3203]

Doing an exothermic weld to extend the UFER ground should be acceptable?


DJR

 

[dpc]

I think what you are proposing would be allowed in the USA as long as you were using approved connectors. If you are in the US, you should review the NEC requirements for grounding electrode conductors in Article 250.

But I would also plan in installing an auxiliary grounding electrode of some type near the new switchboard and bonding everything.

 

[madmantrapper]

I'm not sure what exothermic weld is. We had a similar situation once and we were required to cad weld them.

 

[dpc]

Cadweld = exothermic weld.

 

[1capybara]

i hope there is something else somewhere in the system besides the ufer, becvause concrete is a poor conductor and many slabs are poured on top of a plastic sheet ("visqueen") which insulates the ufer from ground even more. have u ohmed this ufer to ground? is it 25 ohms or less?

 

[waross]

Ufer grounds are prohibited when vapor barriers are used below the slab. Ufer grounds have been proven and accepted by our codes for over 40 years.

Bill
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"Why not the best?"
Jimmy Carter