Water heater electrical problem

[colinhulse]

I put a Seaward 11 gallon tank in two years ago. It has started tripping the 15 amp breaker after heating up the water. I put an amp clamp on it while it was heating the water, it was drawing 4.5 amps. I'm baffled!

[Sailmonkey]

Does it trip the breaker after the water is hot and the thermostat is opening and closing to maintain temperature?

If yes I’d suspect a thermostat that’s grounding while in the process of making or breaking.

[smac999]

how old is the breaker / breaker panel? if it's tripping at 4.5a then replace the breaker.

[capt jgw]

If the water's hot, it shouldn't be drawing anything. Suspect when the thermo switch opens it's grounding to the case somehow. But 4.5 amps? How big is the breaker? One installed on water heater circuit would normally be 15 amps or so, it shouldn't trip less than that. They do wear out though.

[jamhass]

Is the breaker a "simple" 15A breaker, or possibly a GFI or other fault-sensing unit?

[Stewie12]

Replace the breaker first and if that does not cure it then replace the thermostat.

[stormalong]

Check your wiring. I had a wire chafe through on a sharp edge of the water heater housing. The wire was pretty burned before the breaker popped. Probably saved the boat from a fire.

[northwestsailor]

Replace the element. Most likely burned out.

[sailingchiro]

Breaker

[colinhulse]

I replaced the breaker, no luck. I guess the therostat is next.

[Rapanui]

If the breaker a simple breaker without earth leakage detection then it is either some form of intermittent electrical short in the element circuit or something in the breaker environment (heat?) if the breaker itself is ok. If the breaker has earth leakage detection then tripping after a period of time is a well known feature for electric ovens so there are scenarios you could imagine where this could happen on boat circuits due to humidity and salt environment.

[markcouz]

Intermittent fault on heating element is a common problem, the element has an internal heating element covered by insulation and an external earthed (hopefully!) sleeve.

The internal insulation begins to fail, during heating the heating portions expands and comes in contact with the earthed sleeve causing a trip - by the time you put a meter on it it has shrunk back and no longer in contact.

[Malabarista]

I had exactly this problem. Caused i suspect by running out of water whilst the element was still switched on. I replaced the element ( and upgraded to a dual 12/240 volt one) and system is now working correctly

[Turtle Blues]

If you buy the thermostat and element package you can replace them together, otherwise its a 50/50 gamble. If you have an ohm meter check the element first. The wattage should be etched on the outside of the element. With that you can calculate the resistance. a= w/v and r=v/a. An element that is shorting may operate erratically before it goes completely