tractor trips GFCI outlet....help

[Bobvt]

My GFCI outlets (on 2 different circuts) will trip if I plug my tractor in. I believe they are 15 amp GFCIs. Have to run an extension cord to a non GFCI oulet. On my previous tractor I had a 1000 watt heater and it would work fine on the GFCI. When I replaced the heater with a 1500 watts unit, it would blow the circut.

Bob

 

[_RaT_]

My GFCI outlets (on 2 different circuts) will trip if I plug my tractor in. I believe they are 15 amp GFCIs. Have to run an extension cord to a non GFCI oulet. On my previous tractor I had a 1000 watt heater and it would work fine on the GFCI. When I replaced the heater with a 1500 watts unit, it would blow the circut.

Bob

Do these heaters always stay on? I am aware of block heaters, just have never needed one.

 

[shaley]

Block heaters are direct wired and have no T-stat. They just heat the water jacket to whatever the outside temp will allow. If I plug mine in on a 70 deg day the block is about 115 deg in about 3 hrs. I try to use mine only when the temp is below 40 deg. I have a 400w in a 160cu in. engine. I think my Dodge Cummins uses a 800w so a 1500w unit could cause some problems if it was left plugged in.

 

[_RaT_]

Block heaters are direct wired and have no T-stat. They just heat the water jacket to whatever the outside temp will allow. If I plug mine in on a 70 deg day the block is about 115 deg in about 3 hrs. I try to use mine only when the temp is below 40 deg. I have a 400w in a 160cu in. engine. I think my Dodge Cummins uses a 800w so a 1500w unit could cause some problems if it was left plugged in.

I would think it would be expensive to operate. 1500 watts is going to show up on the electric bill. A 1500 watt element can be operated continuosly by a 15 amp breaker provided there is nothing else on that circuit. We use the 80% rule of thumb, that is, a breaker/circuit should be designed to continuously handle 80% of its rating with no problem. That gives 1440 watts on a 15 amp 120V circuit of reliable power to the heater. 1500 is close enough.

 

[SpringHollow]

My 15 year old block heater on my 2120 just started tripping my GFCI outlet about a month ago. I checked the outlet and it was working fine. I replaced the heater with a new one and everything is fine.

Ken

 

[woodlot]

Here's the numbers on the block heater. I measured these data last night in a dark, cramped, very cold barn, so I hope there accurate.

First what I could read on the face of the block heater: Made in Canada; LR1843; x00 watts (I could not read the first digit).

Then the resistance measurments. I measured between the two outter pins and the center pin on the heaters fitting. I assumed the center pin was ground. I got strange readings. I put a prode on the first outter pin, and the other probe to the center pin and my meter showed 1.5 M-ohms and then resistance increased as I held the probes on the pins. I held the probes for about 30 seconds and got up to 2.1 M-ohms. The reading was still increasing but thats all the longer I could hold the probes. The second outter pin -to- center pin reading was the same, it started at 1.4 and increased to 2.0 M-ohms after approx. 30 seconds.

Finally the freeze plug port next to the heater measured 1.575 inches ID.

What's the diagnosis?

 

[shaley]

Well, 1.575 is 40mm. I can't really say about the ohm meter readings. You really need a "megger" to check leakage current to ground.
The NAPA P/N is 605-3032. You might see if they have a unit W/O a cord. The cord is about $20 of the total $45 cost.
Just drain the coolant and unscrew the center screw and the unit will pull right out. The unit has a butterfly tab similar to a toggle bolt which the center bolt will expand after the heater is inserted.

 

[Bobvt]

I don't think my block heater (or ones on previous tractor) had a thermostat. I don't leave my tractor pluged in all the time. The 1500 watt versus the 1000 cut the the wait time in half (e.g. 10 below, approx. 50 minutes with 1000 watt and about 30 minutes with 1500 watt). This morning it was 21 below, took almost an hour before tractor would start.

While a non GFCI 15 amp breaker (1800 watts) can handle 1500 watts, the 15 amp GFCIs are more sensitive to changes in the draw. Plugged in to a GFCI, the heater will run for about 2-3 minute before tripping.

 

[slowrev]

I would think the heater is leaking electricity into the coolant and therby into the tractor, etc. It only takes a few Ma of leakage to trip.