Copper Water Pipe

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Bama_Electrical

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Alabama
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Electrician
I am about to start a new residential job that is all copper water pipes, but the copper is in the attic. Any thoughts on any bonding for copper in the attic? Doesn’t look like it touches the dirt anywhere. I guess it “is likely to become energized” at the tankless water heaters, but the EGC there should suffice. Thoughts?
 
The attic is nicer than other locations. The connection should be accessible, and the attic typically make that easy. Just run a #4 copper up to the attic (if a 200A service) and put a pipe type ground clamp on some part of the pipe in an easy spot to see. Hopefully it doesn't freeze there.

I had one house where they brought that #4 out through the wall under the bathroom sink and it clamped to the cold water pipe there.
 
The copper water piping must be bonded, even if it doesn't qualify as an electrode, just in a different place.
 
petersonra said:
I agree this is a requirement, but what is the point? I can't see any good reason to do so.
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Because of the risk of shock if it does become energized. There is plumbing where we use a lot of electricity.

Remember that most bonding rules were developed during times of only metallic water distribution systems.
 
But those things should have a branch circuit equipment ground that ultimately connects to the water pipe. So the water bond required per 250.104 is a redundant one that is sized per the service conductors. Why this is needed I do not know.
 
suemarkp said:
But those things should have a branch circuit equipment ground that ultimately connects to the water pipe. So the water bond required per 250.104 is a redundant one that is sized per the service conductors. Why this is needed I do not know.
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Yes, now, but:
LarryFine said:
Remember that most bonding rules were developed during times of only metallic water distribution systems.
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. . . and before many EGC requirements.
 
I was thinking more of the truck slammer carrying a bad cord upstairs and letting is lay about everywhere, while it's convenient
to have the GFCI at the end it still has to get there to work!
I think it happens with great reliquary.
National Library of Medicine

It's amazing how creative people are.
 
LarryFine said:
Yes, now, but:

. . . and before many EGC requirements.
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So can't this be fixed? Instead of making it worse.

I have a question. How did they come up with the sizing of a supply side bonding jumper? Not even sure what it is supposed to do. If the overcurrent protection is downstream of the supply side bonding jumper you're not going to get enough extra current through the overcurrent protection device if you have a fault before the overcurrent protection device.
 
A water pipe could carry neutral current even if it doesn't qualify as a grounding electrode. (But the same can be said for gas pipes, which aren't required to have a special bonding conductor...go figure). As far as shock protection, it's redundant with EGCs.
 
Gene B said:
A water pipe could carry neutral current even if it doesn't qualify as a grounding electrode. (But the same can be said for gas pipes, which aren't required to have a special bonding conductor...go figure). As far as shock protection, it's redundant with EGCs.
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How could it carry neutral current? The bond required in 250.104 is for water pipes that are not in contact with the Earth and thus aren't grounding electrodes. I mean arguably anything that is metallic might get energized or might carry current, but everything else that might get energized or might carry current can be bonded by the equipment grounding conductor.
 
petersonra said:
How could it carry neutral current? The bond required in 250.104 is for water pipes tha in contact with the Earth and thus aren't grounding electrodes.
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Yeah, it would be a rare situation. Like two buildings that share a water supply (but separate power), and less than 10ft of underground pipe connecting them.
 
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Gene B said:
Yeah, it would be a rare situation. Like two buildings that share a water supply (but separate power), and less than 10ft of underground pipe connecting them.
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We've actually had this situation for fire sprinkler service. One building was fed by another for sprinkler, but separate electrical services.
 
LarryFine said:
Bad water-heater element
Fault in a well pump system
Fault in a hydronic heat system
Fault in a garbage disposer
Fault in a whirlpool bathtub
Any other place water and power meet up
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Other locations power and water meet up:
Clothes washer
Dish washer
Water softener
Geothermal heating and cooling systems.

Also, the EMP from nearby lightning strikes needs a solid path directly to earth via the G.E.C. system. Most domestic water is brought to the home (if not all the way inside) underground via non-metallic piping. The house piping systems (all of them in my view) are prime to be energized by the strike if it is near enough.

My $0.02 worth
 
GarwoodV6 said:
Also, the EMP from nearby lightning strikes needs a solid path directly to earth via the G.E.C. system. Most domestic water is brought to the home (if not all the way inside) underground via non-metallic piping. The house piping systems (all of them in my view) are prime to be energized by the strike if it is near enough.
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Which is exactly why gas systems with original-type CSST requires electrical bonding to the supply side; to make sure the source and appliance ends are at the same potential.
 
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