tractor trips GFCI outlet....help

[woodlot]

Hi, I'm hoping someone can help me solve a problem I'm having. I own a ford/new holland model 1920 tractor, its a 1997. Anyway, I can't plug the block heater in without tripping the GFCI outlet in my barn. I removed and inspected the block heater cord and it has no cuts, frays, or anything that would indicate a short to ground. The block heater is installed in a freeze-plug port on the side of the engine block. Why would my GFCI be tripping and how can I fix this? Thanks!

 

[rback33]

Is that the only outlet or are there more in a series after that outlet? If there are more, then you are drawing too much between ALL the outlets and that is causing it to trip. I have this same issue with the outlets in my shed. My guess is you have tank or buckets heaters plugged in elsewhere in the circuit that are overloading it.

 

[Soundguy]

Is the block heater using hot/ground or is there a hot /neutral miswire on the plug or receptical. A cheapy electrical outlet tester will tell you if there is miswire at the recep.

Any chance it is just too much of a load? have you tried it in another recp not on gfci but with same amperage breaker.. OR on a gfci not on a sub panel ( like at your house / garage? ).

Sounds like the gfci is sensing ground current and tripping.

Only other time I saw this was with a sears freezer i had in my garage that, if power went off, would trip the gfci when power came back on.. A real PITA.. i eventually wire dthe freezer up to a REAL plug after throwing out the contents for the 2nd time..

Soundguy

 

[rback33]

Is the block heater using hot/ground or is there a hot /neutral miswire on the plug or receptical. A cheapy electrical outlet tester will tell you if there is miswire at the recep.

Any chance it is just too much of a load? have you tried it in another recp not on gfci but with same amperage breaker.. OR on a gfci not on a sub panel ( like at your house / garage? ).

Sounds like the gfci is sensing ground current and tripping.

Only other time I saw this was with a sears freezer i had in my garage that, if power went off, would trip the gfci when power came back on.. A real PITA.. i eventually wire dthe freezer up to a REAL plug after throwing out the contents for the 2nd time..

Soundguy

I had a similar freezer issue.... except it was empty and I was trying to move it back into the house after that part of the remodeling was done. I hosed and scrubbed on since it was filthy before moving it into the house. It would run about 30 seconds and trip the GFCI outlet. Fourth time I gave up and plugged it into an adjacent regular outlet, knowing that the issues was moisture related from the cleaning. Sure enough it ran fine there and about three days later I plugged it back into the GFCI and it has been fine ever since.

 

[ultrarunner]

There is a slim chance the GFCI is defective.

The quality and price of GFCI's receptacles vary from less than $10 to over $100 for Hubbell's Heavy-Duty Hospital Grade #GF8300WA.

 

[shaley]

Wow, I have a NH 2120 and last Dec. my block heater was doing the same thing. I plugged it in to a non GFI extension cord and it seemed to heat for about a day. Bad move. There was water behind the half moon plug at the block heater. It proceeded to electrolyse the copper heater pin away and ruined the unit. If the GFI is not tripping from moisture, chanches are the heater element is breaking down and you have a true fault to ground. It only takes 5 mA to trip a GFI. I'd test it on another GFI circuit to make sure it's not juat a bad GFI. Anyway, it is probably is a 400w 120v made by Zerostart. Mine is a 40mm dia. and NAPA had it for $40 but it came with a 5ft cord set. Advance Auto has the KATS for about $16 but wasn't sure if the cord was the same and I wanted to use my 1ft cord. Measure the freeze plug hole dia on a plug you can get at on the engine and see what size you need.

 

[woodlot]

Thanks for the replies. The one thing I can say forsure is that this is not a GFCI problem. This is a dedicated circit and the GFCI itself is a hi-grade Pass&Seymor. I'm pretty sure that there is a fault.


How hard it it to replace the heater? What's the procedure to get that bugger out & get a new one in? FYI, my heater has about a 5 foot cord and a "1/2 moon" shaped fitting between the cord and heater.

 

[Diesel-ME]

Woodlot,

After you test the heater on a different GFCI outlet (making sure that there is no other load on that circuit), it's safe to assume that the heater is going bad. I had the same thing happen on my PowerStroke. You can probably get away with plugging in to a non-GFCI for a while, but it should be easy enough to replace the heater. Heck, maybe you can ride out the balance of winter and put it off until fall....manyana.....

In any case, if you can get someone else with the same setup to measure the resistance of a known-good heater you could compare. Any cheap-o Ohm meter would work for this. I'd just measure from hot and neutral to ground.

~paul

 

[shaley]

Measure the plug diameter of the one next too it. The freeze plugs are slightly recessed and the bore can be measured with a caliper. They make a 39mm, 40mm, and a 41mm. In inches, this is only 0.040" difference so a tape measure will not be accurate enough. I can post the NAPA part # for the 40 mm. Meanwhile I'll go look at the shop manual and see if it has 1920 data.

 

[_RaT_]

GFCI's trip not from current overload but by loss of electrons. Basically the GFI counts the electrons going in and counts what comes back allowing a margin of loss. I would take a ohm meter and test the heater coil by putting one lead to the coil and the other to the tractor on clean steel. Do both sides of the coil. If you get a reading (lower the number the less resistance the more loss), you heater coil is shorting to the tractor.