Anyone - I need help. Commercial electrician doing friend favor. Upgrading from overhead to new underground 200A service. Installing ufer ground. Panel is on backside of house and gas/water main is in front. How do I run a continuous GEC from ufer to gas/water main. Or do i need to. can i run from ufer gec to neutral bus and out from neutral bus to gas/water? Located in CA thanks.
We almost always run 2 separate runs one to the ufer with an acorn and one to the cold water pipe ground. Mass. I think has no prob with going to the gas but most of ours out here (CA) are yellow tubing, (atleast where I live) so we just use the water pipe and it doesn't scare the inspectors either. I guess it just depends on your AHJ where you are at.
It does not matter if you win or lose but how you lay the blame :-)
yes, concrete encased. So what I'm gathering is I can go gec from ufer straight to neutral/ground bus and out of neutral/ground bus w/ #4cu to water main supply side right? and bond at water heater (cold, hot, gas).... please advise.
A "Ufer" is a ground that utilises the rebar in a concrete slab as the grounding electrode. It is typically made, at the time the slab is made, by attaching 20 ft. of #4 to the rebar at multiple points. A "concrete encased electrode" is typically a 10 ft ground rod, with the top two feet bent at a 90 to the body of the rod. The rod is laid in a two foot deep tranch, and surrounded by twominches of concrete.
The "ground rod" or "grounding electrode" is there to give lightning somewhere to go. On older homes, sometimes a water supply main was used for this purpose, but that practice has ended with the advent of plastic pipe. Today, with a "service change," we end up installing a grounding electrode of some sort.
Another matter is "bonding;" that is, tying to the ground system anything that might become "live" should something go wrong. We "bond" the water pipes, gas pipes, and many other things to the bybtem, typically by running a #8 wire from the item to the ground buss at a panel.
Re: bonding#49286 03/04/0512:36 AM03/04/0512:36 AM
Around here the standard Ufer is a #5 rebar stubbed up out of the slab (bell footer). It is usually a 36" corner bar, snap tied to the footer steel and sticking up inside the block cores. They knock a hole in the block for access and shoot the whole thing green so it doesn't get poured solid when they pour the dowel cells. After the panel is set sparky connects his #4 with an acorn, tapcons a mud ring around the hole and puts on a cover. The stucco guy makes it look nice.
Re: bonding#49287 03/04/0502:11 AM03/04/0502:11 AM
If you're in CA i'm gonna assume you've got a piece of #4 coming out of the slab below your panel. Land it on your neutral/ground bus and from there take another #4 to the closest cold water. Jumper from cold to hot to gas at the water heater if that's the easiest spot.
Re: bonding#49288 03/04/0506:17 AM03/04/0506:17 AM
The NEC does not require bonding of gas piping systems other than with the circuits grounding conductor that feeds the particular appliance...250.104(B)
Interior metal water piping systems are required to be bonded. Generally, the size of the bonding conductor is require to be based on table 250.66, with exceptions for multiple occupancy buildings.
A 10ft ground rod buried in the ground with 2 inches of concrete poured over it is just that. It is not a concrete encased electrode. A concrete encased electrode is require to be a minumum of 20 feet in length...250.52(A)(3)