Block Heater Trips GFCI

[VetteGuy]

I've got an issue with my truck and it's driving me absolutely nuts

When I plug my truck into the outlet at my apartment, it SOMETIMES trips the Ground Fault Circuit Interruptor. I don't know why it does this. I need to be able to plug my truck in because it gets pretty cold here in northeast Ohio and letting it warm up for 15 minutes doesn't really work for me when I'm going out plowing. Does anybody have any ideas as to why it would do this?

Something else I notice. I always plug the truck connector in first, then plug it into the wall. I got a pretty nasty shock once doing it the other way, so I've since then I've been plugging it into the actual outlet second.

[VetteGuy]

Anybody? I really need to figure this out.

[bigcountrysg]

I bet you got a wet plug on your block heater. With the weather we are having. I bet your plug is wet and that is why it is tripping the gfci. I would go out with a flashlight look at your plug and take a dry towel to the plug and extension cord. Dry it best you can and try it again. If that does not work then you might need to replace the cord for your block heater. Or your block heater is shorted out.

[97p-stroke]

have you tried a new extension cord?

[rdodger]

i had the same thing happen to me tonight and also need to plow snow and dont wanna wait forever for the truck to warm up . i plugged mine into outlet first and when i went to plug it into the truck i almost s*#t myself from the shock i got . kinda funny now though . my plug on the truck and the extension cord were both full of snow . would that do it ? i thought i got it all off but apparently not

[VetteGuy]

I've tried 2 different extension cords. Same problem with both. I'd love to just rip that stupid outlet out and put a regular one in, but it's at my apartment complex so I can't really do anything about it.

I'll try taking a dry towel to it next time. Man if that's all it is I'm gonna feel so stupid

[Rav52202]

Im not sure what the amp draw is on the block heater but it maybe border line of the gfci amp rating? Just a thought.

[tony 340]

Had the same problem with my 6.0

Ended up ditching the GFCI for a regular 20Amp outlet with a hinged outdoor cover.

Also got zapped unplugging it in the morning.

[alberta 7.3]

Originally Posted by Rav52202

Im not sure what the amp draw is on the block heater but it maybe border line of the gfci amp rating? Just a thought.

No, the GFCI will either be 15A or 20A rated. The circuitry in the GFCI measures the current between the line (black) and identified/neutral (white) wires. If the two currents aren't equal, there must be current leaking to ground, which trips the GFCI. Make sure all plugs and receptacles are clean of salt and snow, check the cord at the block heater for melting or grease/oil contamination.
Use a multimeter to check for continuity/shorts between the blades and grounding pin on extension cords and block heater cord. On the block heater cord, there should only be continuity from the ground pin to the body/frame.

If you are getting "zapped" there is obviously a problem, and the GFCI is doing it's intended job by tripping.