Article 250.50 Grounding Electrode System. All grounding electrodes as described in 250.52 (A)(1)through(A)(6)that are present at each building or structure served shall be bonded together to form the grounding electrode system. Does this mean that a UFER Ground will be required whenever there is rebar 1/2" or larger in a foundation? Is it still present after the concrete has been poured? What is the best way to meet the requirements on single family homes?

My viewpoint of a Ufer ground is that for a service over 200 amps the length of metal that is in the footer should be increased to more than 20 feet and the wire size should be increased as well.

So far I have inly installed 1 electrical service that used a Ufer ground because most of the work that I do does NOT involve residential new construction. In this case I was building a 400 amp residential sevice using two 200 amp service switches. To avoid using crimpers I used two #4 copper wires each 24 feet long in the footer running in opposite directions. This way I could bond the 2 grounding electrode conductors together using a clamshell terminal.

Mike Cole, mc5w at earthlink dot net

I support the idea that a larger service size will have a lower supply impedance, therefore a higher available ground fault, however I doubt if there's anything official to back up increasing the GEC beyond 4AWG. The reasoning behind the 4AWG size is that the impedance of the UFER ground alone is high enough that the division of ground fault current between the UFER path and the neutral path is such that 4AWG is adequate. If the electrode length and GEC size are increased, thereby lowering the path's impedance, more of the fault will follow the UFER path. I wouldn't want that. I do see an advantage of more UFER capacity in the event that the neutral path is interrupted; then there'd be safety problem. To guard against that the size would probably need to be much greater.

For a 1600 amp feed, you need to provide 3/0 grounding conductor. In the multi-conductor cables, stnadrad 500kcmil cables have only #2 grounding conductor. Do you need to provide a separate 3/0 grounding conductor run along the multi-conductor cables to satisfy article 250-66

what is a U.L. listed grounding tool? isn't a crimper under a Klein pliers a U.L. approved tool?