Why does the circuit breaker for my bedroom continue to trip without any visible event after a power loss?

Question

The 20A breaker for my bedroom will trip whenever we have a power outage at my house. If you reset it, it will trip again after an interval, say 5~10 seconds. The longer you wait to reset it, the longer it will go before it trips. It generally takes 5-6 hours of waiting before you can reset it and and not have it trip again. What might be causing this? Could it actually be a wiring or electrical problem in my house or is it likely that the breaker is failing?

Things connected to the breaker:

1. Two desk lamps
2. One overhead lamp
3. One fan
4. Two desk clocks/alarm radios

Having the lights and fan off does not seem to impact this.

The last time this happened, we contacted our landlord to have an electrician come fix it when we could not get the breaker to stay on. An electrician came out the day after and found nothing wrong and it was working: very unhappy landlord.

Answer 1

Probably a bad breaker, but the symptoms are also consistent with a mild overload causing the breaker to heat up and trip over time, the longer you let the breaker cool before resetting, the longer it takes for it to heat up and trip again.

I'd leave it turned off until you've ruled out a short in the wiring or other overload condition causing it to trip - if it's a short somewhere, that short is causing a lot of heat somewhere in the walls or other inaccessible place.

It's possible that the wiring is not straightforward and there's a load connected to the breaker that you're not aware of - like maybe the toaster in the kitchen is on the same circuit so be aware of what other appliances in the house may be in use when you experience the trip.

The hard thing about finding a short circuit is that if it's due to, say, a bad connection in a junction box under the floor, it may not short out until you walk near it and make the wires flex enough to touch. If you notice any kind of burning smell associated with the trip, keep the breaker turned off until someone finds the problem.

Some types of breakers are subject to "nuisance tripping" even without any overload or wiring problems - if you have an AFCI or GFCI breaker, you could be experiencing nuisance trips due to a device that's plugged in.

If you have 20A service to your bedroom, you're probably in a newer house (15A is more typical, especially in older construction), so a short is less likely than if you're in an older house so the most likely cause of the problem is a bad breaker. Hopefully the landlord had his electrician swap out the breaker since a breaker is relatively cheap compared to having the electrician make another service call.

The consequences of a short somewhere are severe enough (i.e. a fire in the walls or other inaccessible area) that it's worth ruling out a short before you leave the circuit turned on. If the landlord can't fix it to your satisfaction, hire an electrician of your own and bill it back to the landlord. Even if it's just a bad breaker, the landlord is responsible for wiring problems.

The fact that it stays on after waiting 5-6 hours probably means that it's not a short, but I wouldn't dismiss any repeated circuit breaker trips since the circuit breaker is your only warning about a dangerous short in the wiring.

Answer 2

The circuit is either (nearly) overloaded or the breaker is defective.

An ammeter check of the circuit in question is the best way to verify an overload. This is not a recommended DIY test because the breaker box has to be opened and the ammeter put in series with the breaker.

Your list of devices wouldn't normally be close to using 20A, unless a device was faulty.

The electrician could have done the test I described. If the load is normal, replacing the breaker is in order.

Update: To be thorough, the wire gauge of the circuit should be verified (it should be 12 gauge for 20A, 14ga for 15A), as well as doing the load testing... Perhaps this circuit has been a problem before and someone increased the breaker to 20A (from 15A) to eliminate nuisance tripping. Overloaded breakers are not good, overloaded wiring is dangerous.

Answer 3

Perhaps the bedroom circuit breaker is one of the "special extra sensitive" circuit breakers that we have experienced...

Unfortunately when we completely rewired our (circa 1939) cabin we ended up with several circuit breakers which had been manufactured just after a new regulation was put into effect.

The bedrooms due to a new regulation required a new type of breaker which was different from the kitchen/bathroom gfci's. These "new bedroom circuit breakers" are supposed to trip much more easily -- in order to protect silly little children who may put things into outlets.

We found that the ones which had been manufactured during the first few months were especially weird... Supposedly "nothing wrong with them", but replacing them the fixed problem. Note: electrical work was being done while we were doing other remodel work (when walls were open). We were there, so we know which electrical items were replaced when.

Since we were re-wiring everything, meter box, adding breaker box (instead of screw-in fuse box), all work fell under new regulations. i.e., we had to meet "current code". Since you mentioned Bedroom, it set off a little light in my head.... The bedroom breakers are supposed to be more sensitive! We have also found that they are the more prone to behaving strangely. We found that the breakers which were from the earliest ones manufactured under those new regulations are extremely "twitchy"(prone to tripping).

An electrician who has worked in your area of the country for a while would probably be able to replace a breaker cheaper than trying to "figure out what is wrong with it." As our weird "overly-sensitive" "bedroom breakers" were technically working "within spec's", nothing was technically nothing "wrong" with them from an "electrical code" point of view. Replacing the "old design bedroom breaker" (2005) with a "new design bedroom breaker" (2008) helped with the worst one of the bedroom breakers which were tripping too easily.

These "overly-sensitive breakers" were even more frustrating for us, as we had opted to move our electrical panel outside. When the one remaining "old breaker" flips during a thunderstorm, we have to wait for rain to cease, and go outside to open panel to reset breaker. Yet another reason we have UPS's -- so we can gracefully shutdown computers until rain stops.

Because of those "ultra-sensitive" breakers, we try to never have anything plugged directly into the outlets on them. Even plugging and unplugging items would trigger them to flip! Since we have mostly electronics in the bedroom with the most sensitive breaker left, we kinda look at it as an extra protection. Our solution for tripping bedroom breakers when unplugging items was solved by using a battery-backup UPS.

For What It's Worth, here are just some of the things which we no longer experience with our "new bedroom breakers" which used to cause the "extra twitchy" bedroom breakers to trip:

• using remote control on air conditioner (on it's own circuit).
• unplugging a lamp while it was still on (we avoid anyway, but duh!).
• plugging/unplugging vacuum cleaner (good excuse to get cordless vac).
• lightning storm which cause power fluctuations.
• electrical surges/drops which cause our other UPS's to beep.
• turning off switch on conventional "power strip" plugged directly into outlet.

Answer 4

As a former electrician I have real problems with this situation.

1. All devices on branch circuits say lights, radio etc. plug in to wall receptacles rated at 15 Amps.
2. You say the circuit feeding these lights is 20 Amps. This does not provide the necessary protection for the light and receptacle. If the wiring IS 12 gauge the wiring would be OK but the terminals in the receptacle and the wiring inside the light are only rated at 15 Amps. The breaker needs to be replaced with a 15 Amp breaker.