Grounding conductor size for plumbing bonding jumper

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Old 01-07-16, 06:06 PM
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Grounding conductor size for plumbing bonding jumper

I have copper plumbing in the house. Everything appears normal as far as the bonding at the panel and the water pipe entrance to the house, but there are some repairs that were done elsewhere in the plumbing that included SharkBite connectors. Because of their design, there's no continuity across them, so I need to jumper them.

By my understanding, NEC says that conductor size for the jumper is based on the size of the service entrance conductor. Unfortunately, I have no idea what that is. No legible markings on it that I can read. I have standard 200 amp service off of a city grid. The SE is gray, and has a flatter (not perfectly round) profile. It looks like aluminum 4/0 SE cable I've seen in the store, but that's just a guestimation.

If it is 4/0 aluminum, then per NEC 250.66, I would need a 4 AWG copper conductor for the jumper, yes?
 
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Old 01-07-16, 06:43 PM
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#4 CU is for a 200 amp service to a water line.
 
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Old 01-07-16, 09:50 PM
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Interesting you should bring this up as I was just having this conversation. The Shark Bite fittings are not considered 100% electrically conductive.
 
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Old 01-08-16, 03:46 AM
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The grounding electrode conductor from the panel to the water line would be #4 copper for the 200 amp service. If there is no metal water pipe exiting the house underground, this same conductor would be called a bonding jumper. Bonding jumpers across water meter, water heater, etc. would be the same.

But somewhere I read that bonding jumpers across sections of plastic plumbing upstairs would be sized for the largest branch circuit passing nearby which might mean using a 14 gauge conductor. Plumbing hardware such as Sharkbite fittings with not so good electrical conductivity may fit in this category. I don't have the rule in the NEC handy.
 
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Old 01-08-16, 05:05 AM
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If there is no copper water service entering the building then that would mean ground rods would be used,in which case a #6 CU is all that would be required,I believe.
 
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Old 01-08-16, 07:10 AM
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Agreed that SharkBites (and any other push-in) plumbing connector or dielectric unions should be jumpered with a bonding wire. The SharkBites have a neoprene gasket that seals between the pipe and the brass housing, meaning there would be little to no electrical connection across the fitting. Soldered, brass compression or copper-copper union fittings however are OK for electrical connection and do not need to be jumpered.

The phrase in the code is "[metal plumbing] likely to be energized", so you could make an argument that the entire service cable is not likely to energize the plumbing, especially if they are in different areas of the house. In that case you could perhaps choose the largest branch circuit like the range at 40A and say that is the largest circuit likely to energize the plumbing and therefore use #10 copper. Practically speaking, have some jumper there is leaps and bounds better than having no jumper there regardless of exactly what AWG the wire is.
 
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Old 01-08-16, 09:05 AM
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Agreed that it seems unlikely that the service entrance would energize the system, much more likely a branch circuit. I just haven't seen anything in the NEC that makes that distinction.

I guess the real question is, after looking, I have some #6 solid copper lying around. Should I grab a few feet of #4 copper, or do y'all think the #6 would work fine?
 
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Old 01-08-16, 07:18 PM
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I have seen some say tat if there are plastic portion,of the water system there is no need to bond at all since the code says metallic s water system .
 
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