Water Heater Bonding

[dpetro]

Does a electric water heater have to be bonded like a gas water heater?

[Richard Moore]

I'm going to assume you mean bonded at the hot and cold water pipes above the heater.

IF the electric WH was properly grounded, and you could be absolutely sure you had full metal to metal contact at the connections, and the water heater was never going to be replaced, then I guess the bonding strap would be redundant.

However, because of plastic dip-tubes, washered unions, and the fact that all WHs will need to be removed at some point, then the answer to your question is YES, same requirement for gas or electric.

In most homes there is probably effective bonding of the hot/cold piping at the shower mixing valves. I say probably because more and more "stuff" is made of plastic nowadays. Of course, if that valve(s) was removed for service or replacement you could break the continuity of the bond. The bonding strap at the water heater may be superfluous MOST of the time but it's very worthwhile insurance.

[tps777]

I had an electrician tell me a few things today that seem suspect so I just want another opinion.

An inspector told me I had to bond my electric water heater. I tested it and both pipes test for continuity to ground without a bonding wire. But the inspector says I have to bond it anyways.

Since it is electric, and crossing the two pipes seemed minimally useful - I bonded both pipes and continued the solid wire to the ground, so at least I feel like it is actually grounded.

The electrician said I must disconnect the ground connection.

It seems odd to do this, and don't understand how this hurts.

[allseason]

The jumper maintains the bond when the water heater is removed for any reason.

[Jim Katen]

. . . It seems odd to do this, and don't understand how this hurts.

That's because you don't understand what it's intended to do.

The purpose of bonding the water pipes is to keep them at the same potential as the neutral terminal bar in the service panel. This way, any electricity that finds its way onto the water pipes will instantly trip a breaker. Just because you measure continuity between them doesn't mean that the "continuity path" is robust enough to handle a large fault.

To achieve this, the pipes have to be connected to the neutral terminal bar at the service or to some point on the grounding electrode system with properly sized wires and proper connectors. The earth itself is not adequate for this purpose because its resistance is much too high.

Continuing the wire to the ground probably wouldn't hurt anything, but it might cause confusion later, where someone might think that it was part of the grounding electrode system.

[tps777]

. . . It seems odd to do this, and don't understand how this hurts.

This way, any electricity that finds its way onto the water pipes will instantly trip a breaker.

To achieve this, the pipes have to be connected to the neutral terminal bar at the service or to some point on the grounding electrode system

That is certainly a more thorough explanation than I have ever heard.

I'm curious if you don't mind me asking, where is the neutral supposed to be bridged at? Does this have anything to do with the bonding of the ground to the neutral bar at a panel?

[Jim Katen]

I'm curious if you don't mind me asking, where is the neutral supposed to be bridged at?

At the service disconnect.

Does this have anything to do with the bonding of the ground to the neutral bar at a panel?

Yes. The neutral is supposed to be connected to the grounding electrode conductor and to the enclosure at the service disconnect.