bonding copper water pipe

[novemberaudi]

Went to a new house today that had pvc water piping, except for copper pipes from the shower valve to the shower head connection.
In one bathroom there was a 14-2 running horizontally across the same bay as the water pipe. Do these short sections of copper need to be bonded? I have never seen them bonded and have never seen an inspection fail with them not bonded.

 

[infinity]

Bonding not required if it's not a copper water pipe system.

 

[texie]

Went to a new house today that had pvc water piping, except for copper pipes from the shower valve to the shower head connection.
In one bathroom there was a 14-2 running horizontally across the same bay as the water pipe. Do these short sections of copper need to be bonded? I have never seen them bonded and have never seen an inspection fail with them not bonded.

No, it is just an isolated metallic pipe, not a piping system.

 

[GoldDigger]

If the pipe is not likely to become energized, and I do not think that the 14-2 in the same bay affects that, then it probably does not have to be bonded.
It is a metallic part of a nonmetallic plumbing system, not an isolated part of a metallic plumbing system.
I can see arguments in both directions on whether it is marginally safer bonded or unbonded.
FWIW, I think the safest thing to do would be to bond it to the tub drain, whether the drain is bonded to ground or not. But that is not require by any code that I know of unless the shower is within the boundary of a pool area.

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[jxofaltrds]

FWIW, I think the safest thing to do would be to bond it to the tub drain, whether the drain is bonded to ground or not..

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?????

 

[GoldDigger]

?????

Prevents the shower occupant from being exposed to harmful current under any combination of accidental energization of water or drain piping.
If the drain fitting is primarily plastic, with no accessible metal on the outside of the tub or floor pan, then there would be nowhere to bond, of course.

 

[novemberaudi]

OK, thanks

 

[tom baker]

FWIW, I think the safest thing to do would be to bond it to the tub drain, whether the drain is bonded to ground or not. But that is not require by any code that I know of unless the shower is within the boundary of a pool area.

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Then the AHJ sees this and wants it done everywhere. No bonding is required per the code. Washington has a rule that states isolated metallic stubs don't have bonded.

 

[mjmike]

How about a house where the house is all piped with copper supply lines (drains are PVC), but the incoming water line is plastic like with a private well where there is a pressure tank. Is bonding of the copper piping required? Since it converts to plastic before exiting the house, it wouldn't be considered a grounding electrode.

 

[GoldDigger]

How about a house where the house is all piped with copper supply lines (drains are PVC), but the incoming water line is plastic like with a private well where there is a pressure tank. Is bonding of the copper piping required? Since it converts to plastic before exiting the house, it wouldn't be considered a grounding electrode.

It is still a metallic piping system whether or not it is capable of serving as a ground electrode. The code requires that it be bonded. If the only pipe entering the building is non-metallic, then there may be a question as to where to connect your bonding wire, but that does not, IMHO, relieve you of the need to bond.
That part may vary in the interpretation of different AHJs.

 

[Smart $]

How about a house where the house is all piped with copper supply lines (drains are PVC), but the incoming water line is plastic like with a private well where there is a pressure tank. Is bonding of the copper piping required? Since it converts to plastic before exiting the house, it wouldn't be considered a grounding electrode.

That's right... not a grounding electrode and as such will be required to be bonded.

Where there exists a water-pipe electrode, bonding would be covered by the GEC (if piping system is electrically continuous). Don't forget, not just the supply line can qualify as a water-pipe electrode. There could be an underground line running say to another building or structure that qualifies as a water-pipe electrode.

 

[mjmike]

Thanks for the info. I see where it is required by 250.104. So basically, the easiest method to complete this if it isn't bonded, is to put a split bolt on the EGC going to the ground rods and a length of grounding electrode conductor (sized per 250.66) to a piece of cold water pipe closest to the service panel and put a pipe clamp on the line. I would also imagine a jumper should be installed at the water tank between the hot and cold lines.

However, if the ground rods were to fail, and since the interior piping does not go to earth, wouldn't this now create an unsafe situation? Or could this not lead to corrosion of the copper piping?

 

[kwired]

Thanks for the info. I see where it is required by 250.104. So basically, the easiest method to complete this if it isn't bonded, is to put a split bolt on the EGC going to the ground rods and a length of grounding electrode conductor (sized per 250.66) to a piece of pipe closest to the service panel and put a pipe clamp on the line (either hot or cold or both to be safe). However, if the ground rods were to fail, and since the interior piping does not go to earth, wouldn't this now create an unsafe situation? Or could this not lead to corrosion of the copper piping?

That water piping system needs bonded with a conductor sized to 250.66.

Ground rods are an exception that only require a 6 AWG conductor even if 250.66 requires a larger conductor. If you have a situation like that, you must still use the conductor size from 250.66.

If ground rods were to fail so what? All equipment grounding conductors in the premises would be same potential as well. The purpose of a grounding electrode is not to reduce touch potentials within the building it serves and you will typically have similar potential with or without an electrode. Bonding things together is what reduces touch potential. Even if it is 1000 volts to "earth ground" if you are in the shower and the faucet and drain are bonded together you are never exposed to that potential, just like a bird on a wire. Put a probe in the ground and bring a conductor from it to the shower and you may have voltage to that conductor though. Now bond that conductor to the water pipe and you shunt any current away from you.

 

[mjmike]

That water piping system needs bonded with a conductor sized to 250.66.

That's correct, I did say per 250.66. Is it best to see the bond from the copper line be made with a split bolt on the EGC to the rods or to the ground bus in the panel? Using the split bolt would be the easiest method and appears to be allowed per 250.104(A)(1). Also, when checking for tray voltage if the system is not bonded, this could be made from the EGC to the water piping using a DMM prior to bonding. I've read where it needs to be checked both as AC and DC.

 

[kwired]

That's correct, I did say per 250.66. Is it best to see the bond from the copper line be made with a split bolt on the EGC to the rods or to the ground bus in the panel? Using the split bolt would be the easiest method and appears to be allowed per 250.104(A)(1). Also, when checking for tray voltage if the system is not bonded, this could be made from the EGC to the water piping using a DMM prior to bonding. I've read where it needs to be checked both as AC and DC.

The point I was trying to get across is that if you had a 200 amp service - most of the time you will need a 4AWG GEC. But the sole connection to a ground rod still isn't required to be any larger than 6AWG. In that situation you could not tap 4 AWG off the 6 AWG to the ground rod, you must run a 4 AWG back to the service equipment/main disconnect for feeder supplied structures, or you could increase the 6 AWG to 4 AWG if you wish.

 

[Smart $]

The point I was trying to get across is that if you had a 200 amp service - most of the time you will need a 4AWG GEC. But the sole connection to a ground rod still isn't required to be any larger than 6AWG. In that situation you could not tap 4 AWG off the 6 AWG to the ground rod, you must run a 4 AWG back to the service equipment/main disconnect for feeder supplied structures, or you could increase the 6 AWG to 4 AWG if you wish.

That's correct. #6 to ground rod is only permitted where it is the sole connection.

 

[mjmike]

The point I was trying to get across is that if you had a 200 amp service - most of the time you will need a 4AWG GEC. But the sole connection to a ground rod still isn't required to be any larger than 6AWG. In that situation you could not tap 4 AWG off the 6 AWG to the ground rod, you must run a 4 AWG back to the service equipment/main disconnect for feeder supplied structures, or you could increase the 6 AWG to 4 AWG if you wish.

O, I think I know what you mean, my bad. You are saying that the EGC from the service panel to the ground rods may indeed be a #6 (per 250.66(A)). Seeing how the water line bonding jumper needs to be sized per table 250.66, the jumper could be larger than the EGC to the ground rods. Hence, the connection using a split bolt may not be allowed and the connection may need to be made in the panel at the ground bus. Correct?

 

[kwired]

O, I think I know what you mean, my bad. You are saying that the EGC from the service panel to the ground rods may indeed be a #6 (per 250.66(A)). Seeing how the water line bonding jumper needs to be sized per table 250.66, the jumper could be larger than the EGC to the ground rods. Hence, the connection using a split bolt may not be allowed and the connection may need to be made in the panel at the ground bus. Correct?

That is correct and what my intended point was the first time around.

 

[infinity]

O, I think I know what you mean, my bad. You are saying that the EGC from the service panel to the ground rods may indeed be a #6 (per 250.66(A)). Seeing how the water line bonding jumper needs to be sized per table 250.66, the jumper could be larger than the EGC to the ground rods. Hence, the connection using a split bolt may not be allowed and the connection may need to be made in the panel at the ground bus. Correct?

Basically that's it but I think that you meant GEC.

 

[mjmike]

learned something else. I never knew that if you only had ground rods installed that you didn't need a GEC larger than #6. I always thought the GEC was based on table 250.66. I have actually never seen an install follow the 250.66(A) exception; all seem to abide by 250.66 table even if only 2 ground rods are installed. However, I guess it is tough to determine the size of the GEC installed whenever it is solid and bare. Not like there is a sheath with writing on it.

Actually, the easiest fix if there are not openings left on the ground bus in the panel, is to run the jumper outside and bond to one of the ground rods. This appears to be allowed per 250.104(A)(1)