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Electric furnace blowing breaker

26K views 27 replies 10 participants last post by  beenthere  
#1 ·
Have an American standard electric furnace.

Couple times over the past month I've woken up and the furnace hasn't kicked in. Further check shows that the breaker (in the box) has blown.

I'm a rook so excuse the questions, but where should I start first?

Thanks in advance!
 
#3 ·
You need to get it checked by a licensed service electrician or heating tech ASAP. You may have bad connections inside and they WILL overheat, arc/spark and the wiring can melt and smoke and if left long enough start on fire. Seen quite a few roasted electric furnaces in my career.
 
#6 ·
Did it again last night, tried calling a tech today. No one available that's familiar with electric furnaces, but the guy said that the first thing they'll do is change the breaker.

As a side note, the two 60A breakers on the furnace have never tripped on me (I assume one for each stage), only the main 125A one.

I took the clamp on multimeter home from work and read approximately 80A running through the feed wires at first start-up and during regular operation. The connections at the breaker are tight and it doesn't seem to be getting very warm.

I guess I'll try changing the breaker and if that doesn't work, have to wait for a tech to check it out.
 
#7 ·
If you are tripping the Main 125a breaker then it is either:

Main breaker is failing
OR You are exceeding the 125a capacity

What else in your house uses electricity ?

You have (2) 60a feeds for electric heat & only a 125a Main panel ?
 
#8 ·
Hi Scuba,

Sorry I wasn't more clear.

I have a 200A service to the house. The electric furnace has a 125A breaker switch. On the furnace itself is a small hatch, behind it being (2) 60A breaker switches. It is the 125A breaker specifically for the furnace that is tripping on me.

Like I mentioned, I had a gauge on the amperage draw on startup (which I assumed to be where the most draw will occur?) and it doesn't get much higher than 85A. So unless there's a short that occurs at a different part in the cycle, it doesn't seem to be exceeding the 125A.
 
#11 ·
At the panel box. Are you thinking there might be a problem with the wiring between the 125A breaker and the (2) 60A breakers in the handler? I'll have to check that after work.

On the bright side, it didn't kick off last night :)
 
#14 ·
Yeah simple things first then amp readings then solution.

Oh sorry it's back wards first open heater and look around real good and check all connections then proceed to our suggestion.
 
#15 ·
how about checking obvious stuff before the guy starts replacing circuit breakers? like a filter that hasnt been changed in months cusing no air flow across motor or heat exchanger,or a filter wrapped up in the motor causing an overload.definately dont check simple things first! :laughing:
 
#17 ·
OK time to open up the electrical panels on the heater and look at all the wiring and check all connections for loose ness(is that a word?) .Also look for burnt wires.

AFTER YOU SHUT OFF THE MAIN POWER.
 
#22 ·
Connections all seemed fine, didn't see or smell any burnt wires/connections.

I'll try changing out the breaker, probably won't know if it works for a while though, problem is very intermittent.

I'll let you know!
 
#23 ·
Changed the breaker a couple of weeks back and all seems well.

A fellow that does instrumentation work for us is an electrician and offered to buy the breaker for me, little bit cheaper that way. He happened to be in town so came over and looked and found quite a few problems.....

20A breakers where 15A breakers should have been
30A breakers running two appliances (220V hot water heater, 220V dryer, etc)
There was a single pole 40A that he took out, I'm not sure what that was supplying :eek:


So, all is said and done, have a new 125A breaker, 3 new 30A breakers and the peace of mind to know that it's as it should be. The breakers below the 125A seemed a bit loose on the panel, he said it was possible that the heat that was generating was moving up and causing false trips.

Thanks for all the tips, hopefully this'll solve it!
 
#25 ·
Not really. The wire will burn up more as its used. May need an HVAC tech, to find out why its burning. Many electricians don't get involved with electric air handlers.
 
#28 ·
Those are the thermal limits that have the burnt wires. Depends what caused the burnt wires, as to how expensive the repair is or isn't.