Question about hookup of electric furnace

13 years ago

I recently purchased a new place and it was cold outside when I moved in so I ran the heat for about a week before it got warm and it was no longer needed. This electric furnace runs off of 2x 60 amp breakers. One of these breakers tripped several times while I was using it and I decided to turn them both to the off position and deal with this problem as a summer project.

Now that is it hot outside and I am using the AC, I decided to tear into this project while doing some other basic wiring. Well, I opened the breaker box and removed the breaker for the suspect circuit only to find that the two hot wires were not clamped down by the two screws that attach them to the breaker. The breaker came completely out in my hand and was basically not attached. I noticed that the copper wiring was discolored from the arcing and the insulation on the white wire was turning brown from the heat so I assume this is why this breaker was tripping. I replaced the breaker and screwed it down correctly this time. I also checked the others and they were all tight.

I have two questions now. 1) Is there any damage this could have done? Is the wiring or any part of the furnace suspect from this error? 2) The wire is 6-2 with ground. The ground is much smaller and is probably a #12 or #10 at largest. The ground appears to be run as the neutral and this concerns me. I am not an expert at this and it may be ok but the problem with the breaker installation makes me concerned that the person who hooked this up wasn't doing things by the book. Is this ok?

Thanks,

Conor

Sort by:Oldest

Comments (4)

tom_o
13 years ago
1. You've probably found all the damage. Make sure you cut the wire back to a point where there was no discoloring of the insulation. Also, examine the busbars where the breaker was plugged in for damage which will be indicated by discoloring, black marks and possibly pitting. Chances are, this breaker only fed part of the heating elements and not the blower motor or controls, If that was the case, damage to the furnace is unlikely.

2. The equipment ground is probably a #10, and that would be the minimum required size for a 60 amp breaker. Neutrals are typically not needed on this type of equipment, so your equipment ground is not being used as a neutral.

I'm sure that by now you've checked the connection on the other 60 amp breaker and all the connections at the furnace.
0
randy427
13 years ago
It sounds like the furnace was connected with the wrong breakers in the first place. 220V circuits must have both legs disconnect simultaneously.
You need to replace the two 60A single-pole breakers with a 60A double-pole, or otherwise tie the two breakers together so they trip at the same time.
0
Related Discussions
Electric Furnace to Replace Oil Furnace?
Q
Comments (2)
I'm suspecting you live in an area that gets quite cold and is not suitable for a heat pump (except geothermal $$$$$). Heating water resistively would cost a lot more than with oil....
...See More
Oil furnace/heat pump vs hp+ electric strips
Q
Comments (23)
Hi, we have similar situation to research. We are looking into upgrading our HVAC and have question as to go with Heat Pump with Electric or Oil backup. Background: Central Massachusetts, 20 year old house, 3000sqft typical two story colonial with central forced hot air oil furnace and AC. Currently 5ton AC and heating with 80% efficient and I think 110000BTU oil furnace. Which might be more than necessary. No natural gas available. Oil or Propane. 200Amp main panel. Electric rates are about 11.39cents per KWH. Oil rates are about $4.00 dollars per gallon. AC is only two months or so, heating is more important. So we are thinking of choosing a low temperature Heat Pump with good HSFP, SEER is less important. Questions: We were wondering if for the price of electric and oil if we can move to electric as backup in this area (New England). Would there also be any re-sale issues later too? Our dealer is also recommending Byrant 280A 5 Ton low temperature with 20KW, which we might request to bump up to the three stage 24KW heat strips because we keep warm temperature (70F). Thank you for any help you can give.
...See More
Question about home invasions and electricity...
Q
Comments (21)
Sorry, meant to get back last night, but things got crazy around here. Asked DH about the outside circuit breakers. He said he'd seen only a few (actually, not circuit breaker boxes, but FUSE boxes) and they were located at an apartment complex. Which, I suppose makes more sense than on a house. At an apt., management might need to access the box when the tennant wasn't home. DH agreed with me, that it would be extremely inconvenient, because you wouldn't be able to replace fuses in the rain for safety reasons. As to some sort of switch inside/near the meter for turning off service? Not here. The service is turned off at the meter by unlocking the ring, and removing the meter in a certain way so as to disable the connection. He has heard of the switch configuration, but it's not used in our area. Meters and power company practices do vary greatly from one area to another. I was thinking about the exterior circuit box situation and wondered if in some cases it was done that way on older homes that were retro-fitted with electricity after they were built. Perhaps that was the easiest way? As to new homes with that arrangement? Sounds like a contractor taking the easy (cheap) way out. Definitely something I'd want changed at the earliest opportunity--for security, convenience and most importantly--safety reasons. One should NEVER touch any outside electrical connection in wet or damp weather. My husband, a professional with 40 years experience and loads of safety equipment, wouldn't touch a meter or exterior circuit box in the rain. I hope, anyone here who has such a box, will be very, very careful and not let anyone change a fuse, flip a breaker switch if it's raining or the box is damp. Safety first.
...See More
Wiring electric furnace
Q
Comments (18)
Jadriance, We have wired set ups like this before, and some of them were Bryants requiring (2) circuits going to the interior furnace/air handler unit. The box on the furnace was not a sub-panel and it was not intended for only one circuit to be split inside of it. The reason for different circuits from the panel is that one circuit (the 20 amp you mention) is used for the controls only and the other (60 amp as mentioned) is simply a back up heater in case the heat pump cannot keep up with the heating demand. To directly answer your question here is what I would recommend you do: Run your feeders from your main panel to a junction box on the wall, this way you can use NM cable to that point. Install flexible conduit from the wall junction to the furnace and route THHN feeders from the wall junction through the single flex conduit and into the furnace. Most of the units I have seen like this have a large enough knock-out to accomodate the required wiring. The exact number of conductors and size of them would depend upon how far the run is from the main panel and the exact requirements from the manufacturer. As a side note I am really not sure what all the fuss is about. This seems to be a pretty cut and dry issue to me.
...See More
Related Professionals
Wellesley Electricians · Pooler General Contractors · Aurora General Contractors · Clarksville General Contractors · Linton Hall General Contractors · New Milford General Contractors · Pepper Pike General Contractors · Signal Hill General Contractors · Winfield General Contractors · Milpitas Solar Energy Systems · Palo Alto Solar Energy Systems · Gages Lake Home Automation & Home Media · Hollywood Home Automation & Home Media · Libertyville Home Automation & Home Media · Springfield Home Automation & Home Media
countryboymo
13 years ago
I think you fixed the problem

Randy It is probably a air handler with a 20kw strip package which would be 2 60amp double pole breakers of which one will usually run the blower motor and 10kw of strips and the other breaker will operate the other 10kw strip package

Cwatkin.. I would also look into 'staging' the strips with a good thermostat especially if you have a heat pump. On a heat pump it will save a bunch of money. I can explain in further detail if needed either here or post a message in the heating and air side if I dont' catch it in here.
0
dec53
11 years ago
electric furnace has two 60 amp two pole brks.15kw heat strips.
one 60 has two wires from the load side each pole ( four total). the other 60 brk has one wire on the load side on each pole (two total). There is a 2# awg
alum off a 100 amp brk in panel to one 60 and jumper 10# awg
to the other 60 brk. I think it should be a sept circuit, 10# awg
with a 30 amp brk. in the panel to the 60 amp brk. that has total
of two wires on the load side and a 60 amp brk in panel to the other 60 amp brk that has total of four wires on the load side.
I think this is the right way.wright or wrong?
0

Question about hookup of electric furnace

Comments (4)

tom_o

randy427

Related Discussions

Related Professionals

countryboymo

dec53

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US