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E Heat circuit breaker getting hot?

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600SL

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I'm in kind of an emergency situation at the moment with temps dropping down to near 0°F. Two days ago I smelt a burning smell and was unable to determine there it was coming from. Then yesterday I tripped the 2 pole 240V 60 amp e-heat CB, which in turn shuts down the entire heat pump system. I reset the CB and everything was fine until last night when the CB tripped again. So reset it and I took a non contact temperature measurement at the screw terminals on the CB. One terminal was running at ~ 125°F the other one was running ~90°F. Occasionally I would notice a bussing noise. I removed the hot side but really didn't find anything loose or incorrect. Re-torqued it in place and temperature is still about 20 degrees higher on one pole. I ordered a new CB but it wont be in until Wednesday. My question is would this definitely be caused by a bad CB or could the heating coil be a problem. My work around for the next few days will be to steel a 125A breaker from somewhere else but I would really hate to do that if there is a problem with the heating coils
 
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PCustoms

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What do you mean by "hot side", temperature wise or load?

Did you pull the breaker to check the buss?
 
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600SL

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ripperd said:
Can you use an amp clamp to confirm the actual current being used on each leg? That will help tell if its the breaker.
Click to expand...

its running 59 to 62 amps on both legs, I think the CB might be to small so I'm looking into that as well.
 
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mm08822

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Pull the cb and inspect the buss stabs. Are they corroded? Also look at the mating cb interface.

If the buss stabs are corroded, can you locate a NEW cb onto different buss stabs?
As a temp, a 70A cb , maybe 50A cb could get you through for a few days.

Have you measured the amp draw and compared to nameplate?
 
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600SL

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PCustoms said:
What do you mean by "hot side", temperature wise or load?

Did you pull the breaker to check the buss?
Click to expand...

Hot side is temperature wise. Electrically bot sides are hot, single phase 240V US circuit.

I did not pull the breaker out to check the buss. What would I check on the buss.
 
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PCustoms

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600SL said:
Hot side is temperature wise. Electrically bot sides are hot, single phase 240V US circuit.
Click to expand...

Thought so, but worth checking.

600SL said:
I did not pull the breaker out to check the buss. What would I check on the buss.
Click to expand...

Corrosion or evidence of arcing/loose connection.

Only do this if comfortable working in the panel, and ideally with the panel OFF, otherwise the buss will be energized
 
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BillK

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If it has been working fine for years then there is a good chance its the breaker. Its rare that they fail but I have had a couple of them go bad at my shop over the years. Is there no place to get one locally or are you snowed in ? Home Depot or Lowes ?
 
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600SL

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I did confirm that the breaker is too small. Its a 15KW heat coil. Should be 70 - 80 amp breaker. Its been working fine fro three years now but I guess this is the first year Ive had prolonged cold with continuous use of E-heat. I will need to up size the breaker, my wire and disconnect to fix it. I believe I have an 80 amp breaker I can steel from my plasma cutter, if a Siemens breaker will fit into a GE box. I know your not supposed to do that but I'm not worried about it for a few days.

Thanks everyone for the quick replies.
 
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600SL

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BillK said:
If it has been working fine for years then there is a good chance its the breaker. Its rare that they fail but I have had a couple of them go bad at my shop over the years. Is there no place to get one locally or are you snowed in ? Home Depot or Lowes ?
Click to expand...

HD no longer stocks much of GE and there is no lows around me. I tried to go out last night before the snow but none in stock.
 
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rlitman

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600SL said:
...One terminal was running at ~ 125°F the other one was running ~90°F...
Click to expand...
With my thermal camera, 125F isn't too hot (it's only 52C, and wires should be fine to at least 60C or 140F), but the difference between the two, and the fact that you're using a non-contact thermometer has me concerned. IR thermometers under-read the temperature of metallic surfaces, and average the temperature of a wide spot, so maybe your wire really was too hot? The large difference in temperature between the two terminals, and the small difference in current tells me the problem lies entirely between your panel and breaker terminals.

Sure, perhaps a bigger wire and breaker might help, but for starters, it sounds like either your breaker is failing, or it's connection to the bus, or one of the terminals was loose, or the wire in that terminal is oxidized. It's a short list, and all in one place to look. Start checking.
 
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mm08822

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15KW will need wire and cb rated for 80A.

I'm surprised this has just appeared as a problem this late in the game.

What's you typical measured voltage?
 
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PCustoms

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600SL said:
I did confirm that the breaker is too small. Its a 15KW heat coil. Should be 70 - 80 amp breaker. Its been working fine fro three years now but I guess this is the first year Ive had prolonged cold with continuous use of E-heat. I will need to up size the breaker, my wire and disconnect to fix it. I believe I have an 80 amp breaker I can steel from my plasma cutter, if a Siemens breaker will fit into a GE box. I know your not supposed to do that but I'm not worried about it for a few days.

Thanks everyone for the quick replies.
Click to expand...

How are you up sizing the wire so quickly?

Have you checked the buss yet? If you have a problem there then throwing an unlisted breaker in the box may make it immediately worse...
 
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Stuff

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600SL said:
HD no longer stocks much of GE and there is no lows around me. I tried to go out last night before the snow but none in stock.
Click to expand...
GE breakers are history. ABB bought them out a few years ago and now only sells with their name on them. 100% compatible and listed for legacy GE panels.
 
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600SL

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I have a heat pump system that I have just found out needs to have the wiring up sized. Currently it has a 15KW E-heated on a 60Amp circuit 8ga wire, with a 60A disconnect at the indoor unit. Plan is to upgrade to 6ga wire with 70 or 80 amp CB. One question I have is do I need a disconnect at the indoor unit if I the CB panel is 10' away from it and in sight of the indoor unit.
 
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Stuff

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You might have to rethink this as most US codes allow a maximum of 60 amps per breaker for heat loads. I think Canada allows it though. Find the air handler and heat kit manual to see how it shows things should be connected.

424.22(B) Resistance-type heating elements in electric space-heating equipment shall be protected at not more than 60 amperes. Equipment rated more than 48 amperes and employing such elements shall have the heating elements subdivided, and each subdivided load shall not exceed 48 amperes.
Click to expand...
 
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600SL

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rlitman said:
With my thermal camera, 125F isn't too hot (it's only 52C, and wires should be fine to at least 60C or 140F), but the difference between the two, and the fact that you're using a non-contact thermometer has me concerned. IR thermometers under-read the temperature of metallic surfaces, and average the temperature of a wide spot, so maybe your wire really was too hot? The large difference in temperature between the two terminals, and the small difference in current tells me the problem lies entirely between your panel and breaker terminals.

Sure, perhaps a bigger wire and breaker might help, but for starters, it sounds like either your breaker is failing, or it's connection to the bus, or one of the terminals was loose, or the wire in that terminal is oxidized. It's a short list, and all in one place to look. Start checking.
Click to expand...

I put the Siemens 80A breaker in as a temporary solution. Just before pulling the old one out, I took another reading and it was at 135°F. With the new 80A Siemens both sides are running at ~ 80°. With the breaker out I took a look at the buss, nothing obvious but I wasn't going to touch it live. Seeing that the temperature is now stabilized I think the breaker was just defective and probably as a result of operation at its trip limit. That breaker has been discarded.
 
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600SL

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mm08822 said:
15KW will need wire and cb rated for 80A.

I'm surprised this has just appeared as a problem this late in the game.

What's you typical measured voltage?
Click to expand...
Not supersized. The system has only been operational 3 years now. But this is the first winter where E-heat has been on continuously.
 
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600SL

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PCustoms said:
How are you up sizing the wire so quickly?

Have you checked the buss yet? If you have a problem there then throwing an unlisted breaker in the box may make it immediately worse...
Click to expand...

Haven't up-sized the wire yet. Now that I have the problem understood, I'm not too concerned about 8 ga wire carrying 60A for a few days.

I have only checked the buss visually but temperatures at both terminals are now down to ~ 80° so I believe I have that under control.
 
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600SL

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minke said:
What is a bussing noise? 60 Hz? I hope it isn't arcing.
Click to expand...

I hope it 60Hz too. Haven't heard the buzzing in a while. I did notice that one time when turning off the 60A breaker there was a big flash. But that breaker is gone now.
 
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600SL

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Stuff said:
You might have to rethink this as most US codes allow a maximum of 60 amps per breaker for heat loads. I think Canada allows it though. Find the air handler and heat kit manual to see how it shows things should be connected.
Click to expand...

Not sure if this is what your looking for. This is installed in the USA

1769375313531.png
PCustoms said:
As requested in your other thread about the overheating/tripping 60a breaker
Click to expand...
 
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600SL

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PCustoms said:
No, the post above it.

These 2 threads are really the same thing...
Click to expand...

They are turning out to be the same especially if I cant use an single 80 amp circuit. But the question still stands. Do I need a disconnect if I'm in sight of the CB box?
 
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mm08822

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Stuff said:
You might have to rethink this as most US codes allow a maximum of 60 amps per breaker for heat loads. I think Canada allows it though. Find the air handler and heat kit manual to see how it shows things should be connected.
Click to expand...
1769377186006.png
OP needs to look at what he has inside the unit to figure out what size feeder(s) to run. A single to the unit can be run IF internally, it separates the circuits to be below the 60A limit.
 
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mm08822

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600SL said:
They are turning out to be the same especially if I cant use an single 80 amp circuit. But the question still stands. Do I need a disconnect if I'm in sight of the CB box? I will refer all wiring related questions to the other thread.
Click to expand...
If it's in-site (and nmt 50') of the panel then no extra disco needed.

I asked mods to combine these 2 threads.
 
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