i’ve searched some past posts about similar problems, but would like to get your op.
i’ve got a 1987 house w/copper wiring and a GE panel, 200 Amp service. Standard GE breakers with a combination of full and half breakers.
recently, an AC service man noticed my breakers were really hot. he measured 100 degrees with a ‘laser thermometer’ (very neat toy) on one breaker, but all of them adjacent to and ‘across’ from one 15 amp breaker were hot.
At the time, i was running a portable AC unit (because the main unit blew a capacitor) in a room that normally does not have heavy loads on the circuit. wiring is 14ga 15amp. the rating for the portable AC unit is 9Amps. After running all day, EVERY outlet on that circuit and the breaker were very hot.
Adjacent breakers were also very hot.
After my main AC was fixed, i removed the portable AC unit. Now there is no more heating on that circuit, but i have always felt that circuit was overloaded or had high resistance since the lights dim when the TV is turned on.
But since then, i’m paranoid and check the panel frequently. I’ve observed that when running the washer and dryer together, those breakers and the water heater breaker gets hot too (for laundry). These also heat up adjacent breakers.
When the AC is running on a hot day, it compounds the problem, though the AC/fan breakers themselves don’t get hot.
So, i’ve forced my wife to avoid doing consecutive loads of laundry until i resolve it.
I replaced the dryer breaker and the 15Amp room breaker but did not fix any of the problem.
To complicate more, a year ago, I added a 40A double breaker for a garage subpanel (also GE). Neither that breaker nor any of the subpanel breakers get hot. But I had to shift some single breakers down and to the other side of the main panel to fit the double breaker in.
Do i have two problems (1.the hot outlets/breaker plus 2.washer/dryer breakers overheating? Did I create this problem by putting in subpanel breaker (i.e. Do I have neutral sharing problems)?
Do you have suggestions on how to troubleshoot?
Any help? Thanks.
Replies
You'll get a real electrician to pipe up on this sooner or later, but the first thing I would do is pull the covers on all your outlets and make sure all the screw connections are absolutely tight. Turn off the individual breakers first. Also check those screw connections.
If your receptacle connections are just stabbed in to the backs, redo those under the screws.
If an unused outlet in a string is hot, with load somehere, you can bet and win that the connections are somewhat loose.
You can also pull the hot breakers and check the buss connections. If they are burned or pitted you have arcing and heat.
Hot is a relative term. Was that 100F or centigrade? The later would be classified as a real problem. The former less so.
General run of thumb for electrical equipment is the 'hand test'. If you can keep your hand on it comfortably, non-electrified parts only please, it is likely not a major concern.
Breakers should be cooler than even this standard. Warm is OK. Hot not so much. Depends on the situation and loading. A judgment call. A 15A breaker should not, under any circumstances I can imagine be hot. Slightly warm at most. So yea there is an issue here.
Question is what is the fault. I don't suppose the guy put a ammeter on the feed to the breaker running hot. That would have been useful information. I would have checked the voltage across all the connections and through the breaker. More than a tenth of a volt or two, on more heavily loaded circuits, says something is wrong. This is more a comparison than absolute measurement. A bad connection, terminal or bad contact within the breaker.
That the heat is evident in surrounding breakers is not unusual. I would turn off the main and remove all the breakers, preserving their order while doing so. Then I would carefully examine the buss bars, stabs, where the breakers connect to the busses, and the breakers. A strong flashlight and a mechanics mirror are helpful.
Look for darkening, discoloration, pitting or corrosion and signs of excessive heat like contracted or melted insulation, paint or plastic.
If your lucky the problem could be as simple as a loose connection at the breaker. Cleaning and relanding the wire, sometimes just tightening, will take care of this. A bad terminal on the breaker pretty much demands replacement of the breaker. Bad contacts internal to the breaker demand the breaker be replaced. A damaged clamp on the other end of the breaker, where it contacts the buss bar, also triggers replacement.
Things get worse if the buss bar stab, where the breaker grabs it, is damaged. Copper busses can sometimes be cleaned and burnished. Aluminum bus bars, actually tinned aluminum, once damaged can't. You might be able to clean a slightly damged one a bit and smear it with anti-oxidant compound but this is usually a temporary fix.
With a badly damaged stab the best course is to take the breaker off it and relocate the breaker to a stab in good condition. If you have a spare your all set and can relocate the new breaker. If not you may need to change one or more circuits to wafer, tandem or duplex breakers to make room on the remaining good stabs. Care has to be taken to make sure that any shared neutral circuits get on opposite phases. Failing to do this can overload the neutral. Another reason I don't much like shared neutrals in residential settings.
Of course these are the simple cases. Often the load terminal of a breaker goes bad due to overloading, improper termination procedure, especially if the conductor is aluminum, or simple failure to tighten the connection. Seen a few cases caused by overtightening also.
The load-side terminal will overheat and damage the breaker internally. Similarly a bad internal contact can damage the breaker to buss bar connection. Causing arcing that eventually destroys the buss bar stab. Possibly to the point both sides are destroyed and causing both breakers to need replacement. And, as you noted, the heat seldom stays localized. Heat can damage adjacent breakers and connections. Worse case I have seen entire breaker boxes destroyed beyond repair.
Most likely you need to replace the breaker. Assuming it is more than a simple loose connection. Inspecting the nearby breakers and buss bar stabs for damage is a good idea. Of course when you put the new breaker in it will pretty much automatically tell you about an overloaded circuit by tripping.
Lorn, would an out-of-balance load situation at the bus bars cause one of the two bars to overheat? The OP mentioned switching breakers around...maybe one side is carrying most of the load.
I had taken the statement that the heat was centered around a 15A breaker to be evidence that the problem was not at a buss bar, main breaker, level.In my experience the overloading of a buss bar is rare. The Buss bars, each one, are typically rated at the full amperage, at 120v of course, of the panel. If a 15A circuit was drawing 200A I would think there would be other symptoms. Like the fire department arriving.That is not to say that the heat concentration could not originate at a breaker to buss bar connection. This would be much more common. The clamping springs that grip the buss bar stabs can lose strength, or be defective. And the breakers can often, with enough creativity, be installed improperly and make a poor connection that overheats and eventually arcs. Also the wrong brand or model breaker can be installed. Once the connection to the buss bar overheats and arcs it can damage the buss bar. Aluminum buss bars are more prone to this damage. Once their tin coating is holed the aluminum is exposed and corrodes. The main, breaker or lug, connections to the buss bars can go bad. For much the same reasons the load-side breakers go bad.Unbalanced buss bars typically show up as a main breaker tripping. If the main fails because of age, wear or defect the feed lugs or connections usually overheat. Pretty rare and easy to avoid with some common sense. If the breakers are arranged so the double pole ones are run down one side the panel is almost always close to balanced. This also avoids the stabs overheating common when two large loads that draw at the same time are placed opposite each other. A concentration of loads on the stab that can cause any defect in the buss to breaker connection to surface. Not uncommon to have the whole stab destroyed. Not a big problem if there is still space in the panel to reshuffle the breakers.Once or twice I have seen a stab on a buss bar go so far bad that it destroyed the bus bar. Pretty rare. One time we tracked it back to a handyman working for the apartment complex who kept stuffing in new breakers on an arc pitted aluminum stab. Over time it destroyed the buss bar. Got dramatic when the Bakelite insulator holding the buss bar was carbonized enough by the heat to conduct. When I got there the situation was quiet. The vibration of removing the panel cover restarted the bus shooting sparks and arcing across the insulator to the panel enclosure. Sounded like frying bacon.
Thanks.
If the receptacles are hot then I would guess that they are wired to feed through. In other words, the wires from the source are connected to one set of terminals and the wires that go on to the next device on the circuit are connected to the other terminals thus relying on the screws and small strips of metal in the device to carry load through the circuit. This is bad practice and is generally considered to be against the code. When more than one cable enters an outlet box the like colored wires should be twisted together and joined with a wire nut. This joint should include a short piece of wire commonly called a pigtail that then is connected to the device(your receptacle). The wires should not be stabbed into the holes in the back of the receptacle, they should be under the screws and the screws should be tight.
As for the breakers...when one breaker gets hot, it will make the breakers around it hot also. The breakers are attached to a metal buss in the panel. The buss conducts heat to the other breaker(s) that are attached to it. In your panel, if the breaker that got hot was a half size breaker or if it shared a buss tab with half size breakers, as many as four breakers could have gotten quite hot. If this was a prolonged situation(days, weeks, or more) I would recommend replacing all of the breakers on that buss tab. In your case, since the heating was for a much shorter period, I would consider having an electrician check for heat damage on or around the breakers. If you feel comfortable doing this yourself, you can. Your looking for discoloration of the breaker bodies, the breakers' electrical contacts, and/or the buss tabs.
The reason the breakers heated up could be several things. The most obvious and possibly the most common, is that the terminal screws were not tight where the wires are landed on the breaker or the wires were not stripped back enough and some of the insulation is under the screw connection. The breakers could get hot if the were used previous to being installed in your panel(the buss contacts on used breakers are sometimes loose). The breakers can also get hot if the circuit is loaded to the max or near max. If your AC draws 9 amps and you have other loads on the circuit, like the lights and TV you mentioned, you may have had the circuit near max. Did anyone do a load test on the circuit with an ammeter?
As for the other breakers getting hot, depending on how hot,(you are sensitive to this issue now), it may be normal or it may be that the AC problem pointed out one symptom of a bigger problem. I think we need more info to address the other breakers, but I would start by checked to make sure that all of the screw connections on the breakers were tight.
If you haven't drawn blood today, you haven't done anything.
all suggestions are excellent.
the temp was 100F. there were no other lights etc. running when the portable AC was on. So just 9Amps shouldn't have run that hot. especially heating up 4 or so other breakers. it doesn't run that hot on other circuits in the house.
with a cheap breaker tracer i noticed that that tracer was not beeping as readily on one side of the room as the other side though on the same breaker. i traced one outlet and found a splice (a blue plastic and metal splice) in the crawlspace that is not in a box. i will correct that and see if that is the source of the resistance.
i also noticed that the wires to each outlet ARE pushed in; NOT hooked on the screws.
So there are two obvious corrections i can make over the weekend and let you know the result.
I will also check the panel box more thoroughly.
i'm going to buy an ammeter too. i need one anyway.
Thanks!