Water Heater and 120v Problems

So I burned out my water heater element by inadvertently forgetting to turn off the breaker or the outside switch when I drained it last fall, and then plugging in to charge the battery over the winter.  The heater element powered on in a dry tank = burnout.

Not such a big deal, for $10 a new standard 1500w or 1440w 120v screw-in heater element at the hardware store, and online there are lots of YouTube how-to videos on the easy change-out of the heater element.

BUT, a few days of worry because before I realized I had burned out the element in the Spring I had refilled the water system including the hot water tank.  Then my shore power would trip my house GFI plug as soon as I tried to plug in the trailer's 30 amp power cord.  Even after I methodically turned off all the 120v breakers in the trailer's breaker panel, no power could be run into the trailer without tripping a connecting GFI plug at my house.  And I didn't want to chance plugging into a non-protected circuit.

Not being an electrician I was stumped and worried by what could possibly be wrong if all the circuits in the R-Pod were turned off at the breaker panel and I was still unable to connect to my home 120v GFI plug without it immediately tripping.  I wouldn't even be able to charge up my battery ... gaaak!  Could it be water in the plug from when I washed the trailer - or a short in the fridge or AC through water leaking in the vents, or a defective power cord ... or something worse like a short hidden somewhere maybe by a rodent having chewed wires or something.  I spent a few hours mulling it over trying to figure out the possible cause.

Then it occurred to me that the problem was coincident with filling the water heater even though I hadn't powered it up (I had already had the "darn it" moment when I saw I had left the heater switched on by accident when dry, and assumed the element was burnt out and needed replacement).

Lesson learned - the water heater element can have a neutral to ground fault that isn't affected by whether or not the heater is switched on or off at the switch or breaker panel.  When I had filled the tank with water the faulty heater element was completing a neutral ground fault that was enough to trip a GFI plug, which senses faults in both the hot and neutral circuits.

When I replaced the heater element, everything went back to normal immediately.

Whew.  And now I own a handy-dandy standard water heater element socket/wrench (another $10), so I can replace water heater elements to my heart's content at home or in the trailer.

BTW - That outside rocker switch for the electric water heat is placed in an almost invisible spot - I'm pretty sure if it wasn't tucked down like it is, when I pulled the anode to drain the tank I would naturally have switched it off.  Lesson hopefully recalled next year, and the year after that etc,.,

Thanks a bunch Countrygent!   I now realize i've probably had the same problem for the past two years!! I've been wasting lots of time trying to find shorts, knowing the element was toast all the while. Many thanks now know what to do. Tomcamper

Sometimes they can take several cycles to light.  Keep resetting and let the lines purge, you can also light your stove to help speed up the process sometimes.