Electric Heater Tripping Main Breaker

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  #1  
Old 04-15-18, 07:09 PM
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Electric Heater Tripping Main Breaker

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Lennox Air Handler: CBX32M-048

with electric heater: ECB29-15CB-2P (15.0/11.3 KW @ 240/208)
AMPS: CKT 1 20.8/18.1 CKT 2 41.7/36.2

On the unit are two breakers, a 30 amp and a 60 amp. They have not tripped.

The breaker at the main breaker box in the garage trips intermittently during the heat cycle. It is a 40 Amp Double-Pole BR breaker.

Question
Should this be a at least a 60 amp breaker if not an 80 amp breaker? And, if so, can I change out the breaker as long as the wires are the correct gauge?
 
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  #2  
Old 04-15-18, 08:13 PM
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Welcome to the forums.

Normally two cables would be run to the power panel. You can only increase the breaker size in the panel if the wire can support the increase. Check at the air handler end or the panel end for the wire size. It should be on the jacket. Let us know what it says.
 
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Old 04-16-18, 03:52 AM
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Is this a new install? The 40 amp circuit is not large enough to handle the load. A new circuit needs to be run to the garage to support this load.
 
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Old 04-16-18, 08:25 AM
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I could not find the wire gauge size on the jacket but here are pictures of what I've described.

Heat label
https://www.doityourself.com/forum/a...1&d=1523901707

Breaker for electric heater at air handler
https://www.doityourself.com/forum/a...1&d=1523901707

A closer look at the wires coming into the breaker for the heater at the air handler.
https://www.doityourself.com/forum/a...1&d=1523901707

Breaker located in the garage that keeps tripping. This is the breaker I believe should be at least a 60 amp if not an 80 amp breaker. Just checking to see with those that have experience (since I don't).
https://www.doityourself.com/forum/a...1&d=1523901707
 
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Last edited by DYI45; 04-16-18 at 11:03 AM.
  #5  
Old 04-16-18, 08:36 AM
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This is not a new install. We purchased this house last July and the inspector noticed the breaker tripped during the heat cycle. I questioned it at the time and the previous owner had an HVAC guy come take a look. He noted on the invoice that the 40 amp circuit was OK. We went through with the purchase and haven't had trouble until our latest colder weather. I got to checking things out on the internet and based on what I'm reading (if I understand correctly) a 15 KW @ 240 volts should be 62.5 amps. So I believe the circuit breaker in the garage needs to be at least a 60 amp if not an 80 amp. Then let the internal circuit breakers take it from there. I would definitely verify the wire gauge before changing the breaker though.
 
  #6  
Old 04-16-18, 01:12 PM
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I found the install instructions for my heater. It looks like I should install a 90 amp circuit. Correct??
https://www.doityourself.com/forum/a...1&d=1523910120
 
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Old 04-16-18, 04:38 PM
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It is hard to tell what you have by the pictures, Is the heater unit fed with conduit or a cable? If it is a cable, the wires size will be marked on that.

The 60 amp breaker appears to have some of the strands cut off to get the wire to fit. Also, it appears that there is another set of wires coming of the left side of the breaker. Is that feeding the 30 amp breaker?
 
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Old 04-16-18, 04:53 PM
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There are multiple problems here.

1) that looks like some type of #8 copper service cable. Could be confirmed with a picture of where it enters the unit,

2) only one set of wires is allowed to be connected into a breaker. There you have the 30A breaker bridged to the 60A breaker with what looks like #10 wire.

That air handler is setup for two circuits to the main panel. From what I see you cannot increase the main breaker size on that cable.
 
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Old 04-16-18, 05:15 PM
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That air handler is setup for two circuits to the main panel. From what I see you cannot increase the main breaker size on that cable.

I would agree, and that is how I have always done it, but the chart the OP posted says "single point power feed" which confuses me a bit. If it was me, I would run a single feeder to a small sub panel and then feed the heater with separate branch circuits.
 
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Old 04-16-18, 05:24 PM
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That works but an awful lot of breakers.
 
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