Water pipes bonded to grounding rod

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Old 11-02-09, 10:40 AM
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Water pipes bonded to grounding rod

I'm renovating my kitchen, which is next to the water heater and service panel. I came across a bare 6 AWG bonding connector in the ceiling connecting the hot metal water pipe from the water heater to the grounding rod outside. This seems a bit odd.

If this is to comply with 250.104(A), why not just run it to the service panel right next to the heater instead of to the rod on the other side of the house? And shouldn't this be bonded to the cold water pipe as well?

If the water pipes are being used as a GE per 250.52(A)(1), why is this connecting to the hot water feed from the heater? This is also greater than 5 ft. from the point of entrance.

House was built in 1982, but I can't find the NEC that far back.

Thanks.
 
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Old 11-02-09, 12:56 PM
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It is strange that the hot pipe would be grounded. There should be three components here:

1) A copper grounding electrode conductor (GEC) from the ground bar in the main panel to the cold water pipe within 5' of the entrance. Should be #4 for 200A service, #6 for anything less. If you have an indoor water meter you also use this wire to jump the meter -- put one clamp upsteam and one clamp downstream of the meter with the GEC threaded through both so electrical continuity is maintained even if the meter is removed.

2) A secondary copper GEC from the main panel ground bar to the ground rod(s) outdoors. This should be #6.

3) A short #6 bonding jumper from the cold pipe to the hot pipe across the water heater. This maintains electrical continuity between the hot and cold water system as the water heater itself is usually isolated by dielectric unions.

Use clamps like these to bond to the plumbing at the various locations:

 
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Old 11-02-09, 05:34 PM
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Thanks for the quick reply. What you're describing is what I saw in all the books I had on hand as well as in the NEC 2008 code online. #2 is covered, but #1 and #3 aren't. The clamp on the hot water pipe is exactly like your photo, though.

So I guess my question is really whether or not this type of installation was to code in 1982. This house is part of a subdivision of similar houses, all of which went through inspections, and has had very little work done to it. The service panel is original to the house, but the water heater was replaced. It seems like they used the grounding rod as the primary GE and bonded the interior water pipes to it (still doesn't explain why they went all the way to the grounding rod instead of just stopping at the panel). I imagine they forgot the jumper to the cold water pipe when replacing the water heater.

I'm not changing anything electrical. I removed the soffit in the kitchen, and they had this bonding connector running through it. I just have to lengthen it and was surprised to see how it was connected.
 
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