I replaced the above double 60 breaker in my main panel - furnace breaker. It smoked when the furnace came on. I thought I put the black and white wires in the same places where they came from, but I want to be sure, becaue it did the same thing only worse when I turned the furnace on after installing the new breaker and I am going to replace the breaker again, and would really rather NOT burn my house down in the process. I think my furnace has a problem that is causing it to draw too many amps when it calls for heat and I have a service man on the way to check that end. I don't think he will install my breaker in my main tho, so I want to be sure I do it right. I have wired or changed wiring in most everything in my house, so I'm familiar and a can do person, but I haven't messed with the main panel until now. Thannks in advance

 

So why don't you start by telling us why you replace the breaker in the first place.

Did you replace the breaker with an identical make, model, and size? Was the old one bad? How so?

Then tell us more about what kind of furnace you have.

 

Also, if you find the nameplate on your furnace it should tell you the amperage and horsepower if there's a motor, and often will tell you the circuit breaker size recommended. It's hard to believe that a residential furnace would take 60 amps at 220 volts. It should take less, in which case I can't reckon how you could possibly be overloading it.

Also, there is a possibility that you may have the wrong wire size. Your furnace installation & maintenance manual may tell you the recommended wire size, but according to the NEC, and with no other information to go on, a 60 amp breaker should feed minimum #6 AWG wiring.

Juice

 

my furnace (heat pump) had problems, fixed them, but when I turned on the breaker to the furnace on the main panel and turned on the stat to call for heat, the furnace worked, but in about an hour it (the breaker) smelled like burning plastic and smoked. Figured it was better to replace it than hope it wasn't damaged. Replaced it with same size breaker, same type but not same brand name. tried it again and it worked about 3 hours, thought it was ok, went to bed, plastic smell woke me up and it was smoking again. turned it all off, cussed out and went back to bed. I am putting another new one in (to be sure it is not damaged) the furnace was installed 10 years ago by a professional. I am assuming the main panel was also installed by a professional according to local codes. There is no manual, this used to be a rental until I bought it. The unit is a Trane heat pump for a 1200 sq. ft. home.

 

Unless a manufacturer has gone out of business there is always a manual. Look on-line. Call or email the manufacturer.

 

One thing that can cause a 60-amp breaker to burn up is if it is attached to wire that is too small. Do you have 6-gauge copper wire connected to it, or something else? If the wire is smaller, you're playing with fire (literally).

 

the only printing on the wire says type NM B 600 volts, the rest of the wire is down in the wall. The unit has worked (I guess) this way for 10 years, that's when the unit was installed. Right now the 60/60 breaker is completely out of the panel. But did you ever answer my question of whether I had the wires in wrong. The breaker is on the right side of the center column, so the wires come in from the right. Does the white go on top or bottom? That is if everything else is correct. I will get an owners manual, the building is a duplex and my daughter and granddaughters live in the other half and they have the same system. Theirs works ok.

Now something I haven't mentioned, is that on the front of the furnace itself there are 2 60/60 breakers that the wires bolt on both sides, they do not snap in. One of the breakers was bad and the white wire was burned on this bad breaker, in the beginning of this saga. I replaced the bad breaker on the furnace and trimmed off the burned wire to good wire. That's where all this started.

 

The wire are correct. It's pretty hard to get them wrong. It doesn't matter which wire goes on the top and which goes on the bottom.

A breaker does pretty much nothing until you have a fault or overload. And then its function is critical. My best guess is that you have some kind of problem with your furnace combined with perhaps the wrong breaker size and/or wrong wire size.

 

Of course all connections must be tight as well. I've personally had cases were just a quarter turn on the screw that holds the wire to the breaker reduced the wire temperature from about 275 degrees to the room temperature 75 degrees. I found the loose connection by using one of those infrared hand held non contact thermometers. As the currents through the breaker increases the tightness of the connection become more & more important. Fifty or sixty amps is more than enough to generate enough heat to melt wires and cause smoke with a loose connection. The junction between the main panel and the breaker may also be the cause. You could try moving the new breaker to another slot in the breaker panel if you have the room. The excessive heat should cause the breaker to trip if the cause was excessive current draw from the load but I've seen loose connections cause the breaker to trip as well. I'm surprised that you don't have that problem as well.

 

Following jughead's train of thought, it's also a bit worrisome that you switched makes of breaker. Sometimes a breaker not specifically designed for the panel will fit pretty well, but not well enough. This poor fit can cause heat too.

 

Maybe you can tell us what on the furnace needs 60 amps

Is this a gas furnace or electric ?
How many motors does it have ?
Does it run an air conditioner unit ?
How many amps does the heat pump pull ? should have a label on the motor.

Did you change any wires on the furnace, or that goto the furnace ?

 

ok here are the numbers on the unit. it has 1 motor - 1/2 h.p., 3.3 F.L. amps, 200-230 volts. It is an electric unit, it is a heat pump set up with AC. I have a 30/30 breaker in my main panel that is also for the furnace, but has caused no problems. There are 2 breakers for the AC on my main panel a 40/40 and a 30/30. I have a heat pump with auxillary heat from the electric furnace. The aux heat has never been used (heck at this point, the main heat has barely been used by me). I put a thread in the section on heat pumps a while back, but received no reply, so when the breaker acted up, I came to electrical section. You guys are great!

 

You mention "auxiliary heat which has never been used."

Is the control for the A-H manual or automatic? Manual control means the A-H will be in-operative until you manipulate a control-device that will cause power to be switched to the A-H heating elements. Automatic control means a sensing-element will repond to a system-deviation and energize a control that will in turn cause the A-H heating-elements to be energized, the purpose being to keep the interior temperature at the "comfort" value.

An example of automatic control would be an exterior temperature sensing element that would cause the A-H to operate if the out-door temperature fell to 20 degrees.

If my undersatnding is correct, the house HVAC system(s?) includes three 2-ple C-B's at the Service-Panel ( 60, 40, 30), and two 2-pole 60's at the Air-Handler where the blower is located. Best if you can determine exactly what circuits the C-B's protect, and then permanantly indentify them.

Good Luck & Enjoy the Experience!!!!!!!11

 

aux heat is auto controlled. I have the AC identified it is a 40/40 and a 30/30 on one side of the panel. the 60/60 and 30/30 for the heat, aux heat and blower are on the other side of the panel. Yes there are 2 60/60's on the front of the unit itself. still waiting on my service man, they are real busy this time of year, with people like me who wait until it gets cold to worry about this stuff.

 

You've got a big enough load to cause yourself problems if everything isn't right with the breaker. I feel that your origional problem was a loose connection to the wire, that's why you melted the insulation on the wire. Perhaps you can closely examine the breaker to get an idea where it's getting hot. At this point it sure sounds like you have the incorrect breaker for the panel you have. Like John said, the breaker is close to being the right one, but not close enough. You MUST make a low resistance connection between the breaker itself and the breaker box. Any problems with that junction will manifest itself with lots of heat when you put a load on the breaker. I'm thinking that the problem isn't with the load itself because you've never said that any of the breakers you've installed have tripped. I would expect that if you had a problem with the furnace and the load was excessive that the breaker would trip. Breakers that are overloaded will trip without getting hot enough to smoke or melt the plastic if everything else it up to snuff.

 

I seldom say this to people who have the initiative and are honestly trying to DIY, but given the potential risk of loss of life and/or property, and given grandmab's descriptions and questions, I honestly feel there is a chance our friend may not be qualified to safely diagnose and correct this situation. I think it is time to bite the bullet and call in a qualified electrician. This thread is scaring me.

Sorry.

Juice

 

Maybe.
The HI rating of the breakers are to handle the starting current when the pump starts.
This is my guess. the pump circulates freon.
If there is moisture in the system it will freeze, (maybe 10 minuets, maybe hours) the current will increase as the moisture freezes.
the pump will work harder and may stop. this may increase the current to the point the wires will over heat.
You may need to replace the filter / Dryer and vacuum the moisture out of the system for 3 hours or so.

If this is the case the breakers maybe to large for the wires.
You need to get the specs. and check the size of the wires to the breakers.

Like every one is saying big fire hazard.

JuiceHead is right.

 

I may be GrandmaB, but I am not 70 years old and feeble (joke) I am 50, but I am a grandma. I have to tell you all how much I appreciate all your help and wisdom (no joke). I mean that sincerely. Now I have to tell you what the problem was, it was a dumb operator error - mine. The serviceman checked the amp draw on all the furnace wires and they are below what they could be safely, so the unit is ok. He then looked at the burned breaker which I had removed from the main panel and said that from the looks of the breaker and where it had melted, I probably had not seated it good enough on the panel. The first breaker probably was worn out and ready to go anyway and then I messed up the second one. The service man installed a new breaker and wired it for me and checked the 30/30 that I had also installed. And yes, you are right about contacting a professional. After I removed the second burned breaker, I decided not to touch any of it until the service man showed up. I now have heat, have had since 3:30 p.m. CST and all is AOK. I also asked him which breaker controls what on the unit, etc. This has been a real learning experience. Once again, I can't tell you how much I appreciate all the knowledge you all have shared with me and your concern for my safety. Thanks again. I love this site.

 

Here I took responsibility for installing my breaker wrong and was just happy it works now and I was sitting in the living room watching TV when I heard this sizzle noise and walked into the kitchen to see sparks at the 60/60 breaker. talked to the furnace people and they agree something is wrong with that spot in my panel. I am calling an electrician tomorrow. Still no darn heat again tonight. We may have to put another "attractaive" box pigtailed onto the existing one as I only have 1 empty single slot in my current panel. I JUST WANT IT FIXED. Thanks again. just wanted to let you all know "I didn't do it".

 

You could pick 2 less used circuits that you could do without and remove the breakers use those slots for a new double pole 60 temporarily. At least you will have heat.

 

the electrician cleaned off the center column connections and found that the 30/30 AC breaker down one and on the other side of the column was the troublesome breaker, he moved it, changed it and rewired it and so far so good. I keep walking by and feeling to see if its hot and if it smells, not yet. He said its fixed. I am hoping so, I'm tired of this.

 

To be on the safe side.
Get your self some battery operated smoke detectors. and one for us in your breaker panel room.
O and get good batteries.