I have a dual 50 amp breaker in the main box leading to my garage sub-panel. The sub panel has a dual 30 amp breaker on the circut for my dryer. The 50 amp breaker in the main box keeps tripping but the 30 amp breaker for the dryer does not trip. Nothing else is plugged in in the garage.
Could the 50 amp breaker be “worn out” or something.
I have been in the house for about 4 years and never had a problem before about a month ago and its been tripping more often in the last few weeks. No changes have been made to any of the wiring or things plugged into the circut to contribute to the problem.
By dual breaker its two breakers with a little metal clip connecting the switch part, each breaker IIRC is one 110V leg of the 220V circut for the dryer.
Probably someone with more in-depth electrical experience can answer this more authoritatively, but a house I lived in did have a breaker that tripped when both ovens were on. Considering the circuit was designed for both ovens, it seemed reasonable that the breaker should be able to handle it.
An electrician confirmed that it was “worn” and replaced it with the same amp service, and the new one did not trip.
They sure can wear out. I’ve had breakers that mechanically couldn’t stay on - with no power to the panel, they’d refuse to hold in the on position.
Another possibility is there’s a wiring fault - chafed insulation, moisture, mice, etc - between the main panel and your sub panel.
A replacement “two-pole” 50A breaker should be around $20-40, depending on where you buy it and what specific panel it’s for. (assuming you do it yourself) It’s a common size used for electric stoves and ovens so it shouldn’t be hard to find. I’d try that first, before contemplating chafes, mice or wet wires.
Damn straight. I had it happen at my house just this year the switch in question was one of the masters, and for a couple days, we had something like 50% power throughout the house. Basically, the lights would only be half at bright as they were supposed to be, computers and air conditioners didn’t have nearly enough power to work, along with other problems.
And of course, it happens on saturday, on one of the hottest weekends of the summer, gurenteeing that nobody will be able to come out until at least monday.
Mechanically the breaker can wear, this shows itself as tripping on too low a current (they are made to fail safely) other times when it has tripped out on large overloads, you get a black residue inside which is formed by oxidation of the metal contacts during an internal arc, and this can form a conducting path in the current sensing part, this is also known as tracking.Extreme cases can cause tracking across the main contacts or to an earth path.
The units are sealed and non-maintainable and so are faulty.
Is it possible that one leg is drawing way too much current (and the other far too little) and causing the trip on just one half of the breaker ?
One other possibility is that most circuit interruption devices have a fault trip time, some are much more sensitive than others. It is possible that the 30A breaker has a longer fault current tolerance time than the 50A breaker.
Lastly, if there is dampness or dirt inside the 50A breaker it may cause the current sensor to trip out.
Myself I’d favour getting another, but first make sure all the connections are good, if you have terminal loose this can cause a heat build up and cause it to trip too.
Picked up a new 50A two pole breaker (just over $12 @ home depot) will wait till 25th to swap it so I can do it while someone else (namely my ACLS certified wife) is around to call 911 in case my attempts at fiddling with a live breaker panel result in unsynchronized cardioversion.
Not that waiting around for the mrs is a bad idea (which it certainly isn’t) but doesn’t your breaker box have a main disconnect? There shouldn’t be any need to hot swap the breaker.
I looked it over and there does not appear to be any kind of master on off on the box that I can find. Its kinda an old house so I often run across things that are common safety and convenience features in recent years that were not in 1953 when the house was built. Don’t even get me started on the cloth covered aluminum wire rant… At least its a brick house so an electrical fire would have a hell of a time getting a foothold in most of the house.
Circuit breakers will trip when exposed to a slight overcurrent of long duration, or a great overcurrent of short duration. Although not often, I’ve seen breakers become faulty.
Since this breaker is in the main panel, you should be able to replace it with all power off, once you’ve thrown the main breaker.
If, by chance, the breaker is manufactured by Federal-Pacific, you want to replace the panel and all breakers as soon as possible, as the FPE Stab-Lok breakers were known to be problematic.
So long as there are not more than six (6) breakers which need to be tripped to disconnect all power in the dwelling, it is a code compliant arrangement. Exceed six in a panelboard, and a main disconnecting means, either inside or outside, is required.
Regarding cloth covered aluminum wiring-there is nothing wrong with it so long as it is maintained. Note that I’m speaking of 50A and up branch circuit wiring and/or service entrance conductors. Even when the outer insulation fails, a retaping with dielectric rubber and vinyl overwrap will protect the outer neutral for years to come.
As far as a brick dwelling being fire resistant, you’re correct-the masonry won’t burn. Everything else inside will.
Like everything else, YMMV. My mother’s house has no main disconnect other than pulling the meter, and the panel has roughly 24 breakers. The builder was very good at dedicated circuits for things like the clothes washer, disposal, dish washer, water softener, etc. But no main. Perhaps a quirk of the Chicago Electrical Code in 1965?
drachillix - as long as you have the panel open, snug down all the terminals - you’d be amazed at how much those screws loosen over the years. (And don’t forget the neutral / ground bus) Loose connections not only waste power, they make heat, which can hasten a breaker’s demise.
As for the advice on FPE - yes, FPE is bad and has the distinction of having lost its UL listing. But, buying a replacement for $12 strongly suggests that this panel is a “universal” GE / Murray / Westinghouse / Bryant / Sears type.
To the best of my knowledge, the rule of 6 has been around since at least the 1950s, although my Code books don’t go back that far, and there’s no guarantee that Chicago had adopted the NEC back then.
Since you mention the universal type breaker, that brings up another point: just because it fits, that doesn’t make it acceptable to UL. On the inside of the panelboard door is a list of breaker types that are allowed, and if a noncompliant breaker causes a problem, your insurance company could deny a claim based upon that fact.
Siemens/Square D homeline/Arrow-Hart/Challenger/Crouse-Hinds
Gould and Cutler Hammer in addition to the ones you’ve listed will interchange, but aren’t necessarily compliant.
The NEC requires that all devices and components of a wiring system be installed and used in a manner consistent with their labeling and listing, so if a breaker is not UL listed for use in a panelboard manufactured by X, installing it constitutes a Code violation.