My HVAC started tripping a breaker, so I called the HVAC guy to come look see. He told me that the new box I had installed last year (I didn't install it, some contractor did) had too small a breaker for the heat unit. (It's a heat pump)
He said the internal heat coil that cuts on for big loads was doing the tripping. He showed me the wires and we did the math, and he was right. I have no problem with that. I was told to replace the 60A with an 80A. He could not do it w/o charging another service call, he said. I was told exactly what to get, a Square-D 80A "home series" breaker. Home Depot had one, so I got it and brought it home & installed it.
My problem:

The new breaker is about 1/2" longer than the old one and the rest of the breakers in the box. It "fits" the contacts and works fine, but I cannot get it to snap into place, I think it is hanging up on something. Will you look at tyhe picture and tell me what you think is going on???

ANY help would be appreciated.

Take the breaker out and compare the back of it to the one you took out. Pay close attention to the length of the plastic slot where the buss bar tab goes in. It's probably too short, a common problem when mixing different makes of boxes and breakers as some buss bar tabs are a little wider than others. Square D, Siemens, GE, etc. Take a dremmel wheel and trim a little of the plastic away to make the slot a little longer, 1/8" or so to match the one you took out. You may have to lengthen the depth of the plastic slot on the side of the breaker as well to get it to go all the way in. Look carefully and you may be able to see where it is hitting the buss bar tab.

Note: In some areas insurance companies are getting picky about mixing components. I have heard of them balking on claims if a fire occurs, an electrical problem is the source AND there are mixed brand components in the main box. ie.. GE box Square D breakers etc... even though they all meet the proper spec.

Man, that's a great start! Thanks!

The HVAC guy said the box WAS a Square-D, so their shouldn't be any component mixing. I will look though, to see if I can fix it as per your reply. I may take the old 60A breaker with me to see what looks just like it.
The old box was an FPE and I was told that the breakers were getting pricey. Since I was having part of the house remodeled, I went for a new box to carry the extra circuits.

You shouldn't need to dremel the breaker. As silly as this sounds, make sure the wires are not stressed in the outward direction. Sometimes heavy gauge wires can push the breaker out.

DO NOT DREMEL THE BREAKER!!!


That said yes take the old 60A breaker with you. Better yet go to an electrical supply store and have them match it up for you. There are a few different Square D breakers and they are not interchangeble. It looks like you have the wrong one there. Also check to make sure that the wire going to the unit from the breaker is large enough to carry the 80 amps. Also on the heat pump there should be a tag that says what size breaker or fuse is needed to protect the unit.


I do HVAC for a living so feel free to hit me up with any questions you may have.


Edit to add:

The left side of the breaker, where the wires come in, should lock in first then you push the right side (center) into the buss bar. If the left side goes into place and the breaker is still too long you definitly have the wrong breaker. I'm not sure how much experience you have so I'm sorry if I'm stating the obvious to you. And for gods sake be careful in there!!

Brett, thanks! I pushed the contact side into the buss bar first. Maybe that's the problem. I will reverse the order this evening. Dion, thanks, but I did factor in stress placed by the wire...not a factor.
As far as being careful, I work sober around that kind of amperage.

No problem!


I like to have a couple of beers first. It takes away the nervous shake

Philip, Sorry if I'm coming in late on this.....maybe you've got it fixed by now. Anyway, Square D company makes a line of breaker panels called "Homeline" and they are a cheaper quality, cheaper price unit than the standard Square D unit. Consequently, the breaker are NOT interchangable between the standard unit and the homeline. The standard unit uses a "QO" breaker in it and will not work in a homeline and vice versa. As I was looking at the pictures that you posted, it looks like you've got the right breaker, you just didn't get the breaker installed correctly. Slip the notch that is on the end of the breaker by your A/C wires, onto the matching piece on the breaker panel...........Then......slide the "contact fingers" down onto the buss of the breaker. Hope this helps

Breakers are for pussies!!!


Rip that shit out and jam a couple or 10p nails in there!!!