Block heater trips breaker

[JMarchant]

Hi - I have a John Deere 301A with a block heater. Sometimes it will heat the block without problems but most of the time it trips the breaker within 10 seconds or so. The heater has about a 6' cord and I'm using a heavy duty 8' extension cord. Do you think the cord is the problem? I was thinking about installing a new receptacle so I could plug the heater in directly - do you think that would help? Thanks

 

[marchanna]

I shouldn稚 trip. The more powerful block heaters are 1500w which is about the same as a hairdryer. More than likely though, yours is 400w. Have you checked to see what else is on the circuit?

 

[jeff9366]

Breakers deteriorate over years. How old is your wiring?
Most home circuits are 15 amps, so a 1,500 watt load is near max with a NEW breaker. Start up surge requires more power than later run.

If you install a new, more convenient receptacle be sure to include a GFI so you do not electrocute yourself.

 

[marchanna]

1500 Watts is 12.5amps on a 120v circuit, so that in and of itself won稚 likely trip it, but it doesn稚 leave a lot of room for anything else to run a 15amp circuit. But like I said, you probably have a 400w heater which is only 3.3 amps.

 

[dieselcrawler]

Try plugging in another high-wattage item, like a hair dryer, and see if it still trips. Try plugging in block heater to a different circuit, and see if the different circuit trips... isolate the issue using the process of elimination.

 

[marchanna]

I would start by plugging it into another circuit. Preferably one with a gfi. If it pops the breaker then the circuit is overloaded. If it pops the gfi then there is a short in the heater and/or it痴 power cable.

 

[4get gto]

You might able to check the resistance in the heater element. Higher reading probably tells you it not good. I would think it's going bad.

 

[JMarchant]

Thanks everyone,
The wiring is new and this is a dedicated circuit. I tried a new 20amp breaker - no luck. I tried installing a different receptacle - no luck. When I plug in a 1750 W heat gun, it works fine. When the block heater causes the trip it takes 10s or so to happen which seems strange (if a short I would think it would trip immediately). The heater is new last spring. Very strange!

 

[4get gto]

Can you replace just the cord on the heater. Least that would rule that out.

 

[crazyal]

Is it a GFI breaker?