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We recently upgraded our electric service...had to put in a new panel, etc. The city inspector came by and said that everything looked good except that we still need to "Bond Hot-Cold-Gas with #6" @ the water heater. My question is why do we need to do that?

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Because your water heater has dielectric unions, so the hot and cold plumbing are isolated from each other. Bonding the plumbing, attempts to keep the hot and cold plumbing at the same electrical potential.

If this bond is not in place, it's possible for the hot and cold plumbing to be at different voltage potentials. Which means if you grab a hot and cold handle, you could complete a circuit.

It also allows the plumbing to act as an effective fault current path. So if wiring faults to the plumbing, a breaker will trip.

A jumper should be installed across any other break in the continuity as well, e.g. water meter, nonmetallic plumbing, etc.

  • Hi Tester101: I updated the question description. What the inspector actually want is to bond Hot Cold AND GAS line. So we did that today. Does this mean that we need to go to the gas meter and put a jumper across the gas meter, too? – milesmeow Jun 21 '16 at 6:24
  • That's a strange request. Is the water heater supplied with electrical? I don't think a jumper across the meter is required, but I really don't know. Your local town, or the gas supplier might require it. – Tester101 Jun 21 '16 at 11:21
  • The code only calls for gas piping to be bonded, where it may become energized. If there's no electric power going to the water heater, I'm not sure how the piping would get energized. Maybe it's a local amendment. – Tester101 Jun 21 '16 at 11:23
  • I think the inspector is referring to the 'gas water heater", not the gas meter. Hot/Cold pipes are required in some jurisdictions, and as mentioned in my answer, so is the pressure reducer valve. All done for the sake of protecting plumbers. – Kris Jun 22 '16 at 1:11
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The reason the hot and cold lines are jumped ( bonded ) at the hot water tank is to protect Mr. Plumber during future repair work.

The jumper protects the technician from becoming energized by improper current on the system ground by forcing the current to go through it.

Also, a jumper should be on the pressure reducer valve for the same reason.

  • One jumper from pressure reducer valve to hot or cold pipe on water heater right? Assuming that the hot and cold are bonded of course. :) – milesmeow Jun 17 '16 at 17:26

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