Water heater, electrical enigma

dlochner · Jan 22, 2023

Is the water heater on its own breaker?

Is the main breaker an ELCI? If so the issue may be a small fault in the circuit or the water heater. The heater would work on any circuit that was not protected by an ELCI or GFCI, but would not work on a circuit that was protected.

Stu Jackson · Jan 22, 2023

TumbleNor said:
Do you have any idea what could be wrong?

Whenever there is an intermittent issue with electrical, it is 99% of the time in a connection. Check them all, not visually alone, remove and clean and reinstall each one.

Head Sail · Jan 22, 2023

Could also be a bad breaker. Take it out and inspect for burn marks.

Tally Ho · Jan 22, 2023

It sounds like your water heater has a plug in it? Am I reading that right? So you can plug it into an extension cord to shore power or into an outlet on the boat? Or plug some other heavy load device into the outlet to test the circuit?
what other loads are on the circuit breaker that the outlet is fed from? Or is the outlet for the WH the only thing on that breaker?

You did some good investigation work to figure it out…zi am as perplexed as you based on your experimentation.

Greg

TimFromLI · Jan 22, 2023

I had an issue on a previous boat where the water heater would trip the GFCI every time the breaker was turned on. It turned out that the heating element was corroded and shorting to the ground. Replacing the element was fairly simple. Remove the element and see if it looks corroded or broken.

JoeWhite · Jan 22, 2023

What happens if you disconnect the water heater power wires from the water heater and connect it to a power drill machine. In other words replace water heater with something else. If the circuit breaker turns off the power then there must be a short on the wires.

Rich Stidger · Jan 23, 2023

Easy check for a total/partial short- AFTER disconnecting the water heater power connections, measure with an ohmmeter between the securing of the heating element and each power connection. The resistance should be infinite indicating an open connection. If you have a short in the element, it will indicate a low resistance. A low resistance would indicate a failed heating element.
IMHO a failed heating element is the most likely fault given all of your previous troubleshooting and testing.

Tally Ho · Jan 23, 2023

Rich Stidger said:
Easy check for a total/partial short- AFTER disconnecting the water heater power connections, measure with an ohmmeter between the securing of the heating element and each power connection. The resistance should be infinite indicating an open connection. If you have a short in the element, it will indicate a low resistance. A low resistance would indicate a failed heating element.
IMHO a failed heating element is the most likely fault given all of your previous troubleshooting and testing.

Seems like it to me too, but the fact that he can plug the WH into a land power connection and it doesn’t trip seems odd. Is there something in the boats GFI system or something that could cause this?

Greg

Johann · Jan 23, 2023

Tally Ho said:
Seems like it to me too, but the fact that he can plug the WH into a land power connection and it doesn’t trip seems odd. Is there something in the boats GFI system or something that could cause this?

Greg

The boat may have a residual current device (RCD, ELCI, GFCI) with a 30mA tolerance. So if the water heater is leaking 30+mA to ground that would trip the boat breaker, but maybe not the pedestal unless the marina electrical has been recently installed or upgraded.

http://electricshockdrowningmn.com/Documents/Marina%20GFP%20Concerns%2001-03-2017.pdf

leo310 · Jan 23, 2023

Check you wire from the breaker to the heater or just replace it as what you have stated so far is bypassing the breaker/wire everything is ok only when you use the normal route breaker to heater it fails. You may have a lead that is shorting out to ground.

Barnacle Bill · Jan 23, 2023

Tally Ho said:
It sounds like your water heater has a plug in it? Am I reading that right? So you can plug it into an extension cord to shore power or into an outlet on the boat? Or plug some other heavy load device into the outlet to test the circuit?
what other loads are on the circuit breaker that the outlet is fed from? Or is the outlet for the WH the only thing on that breaker?

You did some good investigation work to figure it out…zi am as perplexed as you based on your experimentation.

Greg

No, water heaters don't have plugs on them to insert into an outlet. It is hard wired into the AC electrical system and through a switch.

BarryL · Jan 23, 2023

Hi,

Here is a picture of the water heater on my boat. It has a euro style plug that goes into the box. Mine is not hard wired. I do have to turn on the breaker on the panel to energize the outlet. This is a Jeanneau factory installation.

Barry

Alan K · Jan 23, 2023

That's a 240v male connector. This is a French-made vessel. In 240-volt countries, like France, the two pins are +240V and Neutral. In the 120v USA, 240v devices are served from two pins, each of which are +120v to Ground (180 degrees out of phase) and 240v to each other. A third Ground wire is required with this kind of 240v service derived from 2 hot 120v leads.

I'd guess that something has been changed along the way to create confusion between 120 and 240-volt supply connections.

JoeWhite · Jan 23, 2023

leo310 said:
Check you wire from the breaker to the heater or just replace it as what you have stated so far is bypassing the breaker/wire everything is ok only when you use the normal route breaker to heater it fails. You may have a lead that is shorting out to ground.

And yes, that is what I am thinking is the problem.

Tally Ho · Jan 23, 2023

Barnacle Bill said:
No, water heaters don't have plugs on them to insert into an outlet. It is hard wired into the AC electrical system and through a switch.

TumbleNor said:
Is it the water heater?

The answer seems to be NO. When I plug the water heater directly to the land electricity (without going through the boat’s electrical system), it works just fine. It draws 1200 watts, as expected, and the water is heated as expected.

Then the problem must be the electrical system in the boat. Right?

Well, the answer seems to be NO. When I plug heavier loads (over 3000 Watts) to the very same power outlet, the breaker does not trip. It only trips with the water heater. The boat’s electrical system seems to be somehow “allergic” to the water heater only.

I know mine is hard wired to the breaker in the electrical panel, but the original post leads me to believe that has a plug plug wired to the lead to the awash, and that is plugged into an outlet somewhere…hence my question.

Greg

Barnacle Bill · Jan 31, 2023

Normally hot water heaters are hard wired into the boat's electrical system. Of course, you can attach a regular house outlet plug to any AC appliance and make it work. But, it is convenient to have a switch on the electrical panel so you can quickly shut the power off to the heater and also, it would be wired through a breaker, which is safer than a heat plugged into an outlet. I always switch off the hot water heater when away from the boat for any length of time. That way, I am assured that the water heater will not fail because of a break or leak in the water hoses, which might drain the heater and hence burn out the heating element.