It's damn cold out and I need to plug my truck in at work. Everytime I do it and I'm out of town every gfci outlet trips. If I plug it in at home it doesn't trip at all. Is my element going bad? I replaced the plug end of the block heater cord a long time ago and run a short extension cord off it. If the hot and neutral are backwards that shouldn't matter?
Blockheater tripping gfci
- Thread starter 08lmm72mm
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GFCI's monitor the current going out the hot and returning through the neutral. if there is an unbalance between the current in the two lines over the set limit, usually around 5 mA then the GFCI trips the power.
what is likely happening is there is moisture conducting a small amount of current away from the heater and down to ground via the vehicle. I would carefully inspect the cord and connection at both ends for split or cracked insulation. there should be no difference between hot and neutral as the heater wouldn't care and the GFCI can't tell. does it trip with just the extension cord and no heater? will other items plugged into the cord trip it?
in lue of replacing the heater you can always use an isolation transformer which will decouple the two gound references and keep the GFCI from tripping while still providing protection from shocks
what is likely happening is there is moisture conducting a small amount of current away from the heater and down to ground via the vehicle. I would carefully inspect the cord and connection at both ends for split or cracked insulation. there should be no difference between hot and neutral as the heater wouldn't care and the GFCI can't tell. does it trip with just the extension cord and no heater? will other items plugged into the cord trip it?
in lue of replacing the heater you can always use an isolation transformer which will decouple the two gound references and keep the GFCI from tripping while still providing protection from shocks
I'll have to wait until this blizzard we are getting dissipates. It works just fine plugged into a non gfci. I should try unplugging the block heater cord from the element and then plug it in? If it was shorted wouldn't it trip a non gfci then?
I wouldn't necessarily call it a short. more like leakage current. breakers have current limits of 15 or 20 amps for most outlets. that is orders of magnitude more then what will trip a GFCI. breakers are to protect the wiring in the house/structure. GFCI's are designed to protect you from shocks or electrocution.
a GFCI is supposed to trip before the current that is not correctly going through the intended circuit reaches a deadly level. infact it is normally set low enough that you may not even feel a shock before it trips. breakers in your house that are designed to prevent excessive current from burning your house wires in the wall will not trip at the levels the GFCI's operate at. infact you'll probably have smoke coming out of your ears before you overload the breakers
what you are looking for is a place that moisture can contact the copper in one of the lines and bleed away some of the current. this can be hard to find sometimes. it may be as simple as the plug itself having just enough moisture. or it can be a split in the insulation of the cord somewhere
I will say my LMM heater routing had the power cord rubbing up on some support structure. Just enough to expose a small bit of wires. Wrapped it in electrical tape took care of that. I would suggest just looking at the routing of you power cord and look for something rubbing against it. Probably just enough to make some continuity to the ground wire to induce the GFI to trip. Dean
I feel like not all GFCIs are created equal. I've had some trip more often then others especially when under a high load.
No real reason you should need to keep your truck plugged in another in your own comfort. It should start fine. Would anyone notice at work if you swapped it out for a regular outlet instead of GFCI?.... lol
No real reason you should need to keep your truck plugged in another in your own comfort. It should start fine. Would anyone notice at work if you swapped it out for a regular outlet instead of GFCI?.... lol
Get yourself a new cord. It’s probably cracked where you can’t see it.
BMI Engine Block Heater Cord Compatible with: GM Chevy GMC 6.6L Duramax 2003-2018 https://a.co/d/9L1C4Ao
2013 Sierra SLE 2500HD Crew Cab
BMI Engine Block Heater Cord Compatible with: GM Chevy GMC 6.6L Duramax 2003-2018 https://a.co/d/9L1C4Ao
2013 Sierra SLE 2500HD Crew Cab
Outside temps are currently -30c/-22f . I have new batteries in the truck but they are talking its going to get colder yet and I'm not one to have the excuse my truck won't start to not goto work lol.
I was thinking about picking this one up https://www.napacanada.com/en/p/TMR3600006?impressionRank=1 . Hope it doesn't have that stupid tstat built into it.
I was going to order that exact one you posted yesterday but can get the napa one for half the price.
I run my block heater on a GFCI protected circuit (GFCI+Arc Fault breaker, not the cheap garbage GFCI outlets) and it works fine. My cord is in sorry shape too, the inner conductors are flapping about in the engine bay. But, the inner conductors are clearly not cracked or shorting, just the outer overmolding is failing.
If it was me, I'd pull the cord off the block heater, and plug it in to power. See if that trips the GFCI. If so, the cord is bad, grab a new cord. If it doesn't trip, then the element itself is likely cracked, and will need replaced.
Side note, why the hate on the thermostat cords? Are they not reliable? Or are people plugging their truck in above 10°F for some reason?
If it was me, I'd pull the cord off the block heater, and plug it in to power. See if that trips the GFCI. If so, the cord is bad, grab a new cord. If it doesn't trip, then the element itself is likely cracked, and will need replaced.
Side note, why the hate on the thermostat cords? Are they not reliable? Or are people plugging their truck in above 10°F for some reason?
some plug in just to get some heat from the vents sooner even if they have no issues starting
you can try dialectic grease on both ends of the cord and terminals and see if that helps
failing that, you can always place a bucket of coal under the truck
As far as I know my year didn't come with the the tstat cord and when I work out of town I don't pay for power anyway, it mostly comes from diesel generators or hotel. I prefer to be easier on my bearings in the bottom end avoiding cold starts if possible.
I just read the tstat is in the plug end of the cord. I cut it off and replaced it with a normal end a long time ago.
If all glow plugs are working, it'll likely start fine, even in Saskatchewan. My truck hasn't had a block heater plug since I did my engine swap a decade plus ago, and I have four bad glow plus, and it still starts in single digit temps. Sounds like a tractor and smokes like a banshee for the first 30-90 seconds, but it starts.
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Sure it’s nice to know when you’re in the bush your truck will start but if you can plug it in, why wouldn’t you?
2013 Sierra SLE 2500HD Crew Cab
2013 Sierra SLE 2500HD Crew Cab