We had a GE microwave that was about twenty years old. Latterly, it started blowing the fuse if i ever ran it with the (gas!) oven on. i figured it had a problem with power consumption.
My neighbor bought all new samsung appliances and said i could take her perfect working GE microwave which is about fifteen years newer than mine was. So i switched my old one for the neighbors newer one.
Now the fuse blows every time i turn the microwave on!!
Besides, of course, only running mine at half power, is there anything I can do to stop the fuse blowing please?
Are you using fuses or circuit breakers? How many Amps? How many Volts? How many Watts is the microwave?
If a circuit breaker, it is possible you have one defective that blows at less than rated current.
You might just have a defective Microwave. Or you might be using a high-power coffee maker at the same time on the same circuit.
Note that a microwave running half power, may be running full power half the time.
I am running an 1100 Watt GE Microwave that has no trouble on a 120 Volt
20 Amp circuit breaker.
My circuit breaker is 120V * 20A = 2.4KW. An internal Microwave label says 1.5KW, which is 120V * 12.5A. If yours is the same, you should get by with a 15A breaker or fuse @120VAC with little else on the circuit.
Thanks for this guys but it hadn't struck me that the circuit breaker might be bad. It makes perfect sense. the only other possibility is that whoever wired the breaker box put too much on that circuit, which is something about which we wondered ever since we moved in.
This circuit breaker plainly can't take whatever is on the circuit, - while the probability is that the newer GE Profile microwave uses LESS power than the ancient GE Profile, not more!
How difficult is it to change an individual circuit breaker in an 8 fuse box please? And can i test whether is (and one other CB which is also blowing far too often) is performing to specs? this is the original CB box that has been in the flat since the building went up about 40 years ago.
6 of the fuses are 20 amp breakers, while the one which blows constantly is a 15 amp one! And although I have a theory that fuse boxes tend to have been installed by competent licensed electricians when the building went Various appliances in the kitchen (but not the fridge or dishwasher or washing machine), including the oven, all wall socket powered lights and 23 pieces of TV/stereo equipment in the living room, all wall socket powered lights, stereo and television in the bedroom etc!!
I have always wondered whether doing all this on one circuit breaker was asking-for-trouble. With all the stereos, TVs, lights etc , that 15 amp CB would ALWAYS blow when i turned the old microwave on when the oven was on. Now it blows even when the oven isn't on.
A 1500 watt microwave should NEVER be on a shared circuit. Assuming this is a 120 volt circuit, it requires the total capacity of a 15 amp circuit. Current code REQUIRES a separate dedicated circuit for the microwave.
The microwave should be the only device operating on the breaker. It is right at the limit of a 15 amp breaker.
What else stops working when the breaker trips ? If anything, I would say you just have the circuit overloaded and the breaker is doing its job. If a breaker is reset many times, it can become weak or defective.
One minor point, if you actually have breakers , do not refere to anything as fuses or fuse boxe. They are breakers and the breaker or panel box.
You asked how hard it is to change a breker. Not very hard. You cut off the main breaker, open up the panel box , check with a tester to make sure the power is off below the main breaker. Unhook usually one wire from it that goes to the circuit. The breaker will snap out.It may have a screw holding it in. Reverse the process to get power back on. There are several companies and types of breakers, so you have to make sure you get the correct one. Replace it with the same amp rating. They are there to protect the wiring.
If you have never been in a panel box, do not do it because even though you cut off the main breaker, there is still some 'hot' wires in the box.
I think you said there were only 8 breakers. This must be a very small house/apartment or an older house that was rewired and changed from fuses to a breaker box.
You should know what's on it by now and be able to figure out the approximate load.
It's easy, but you have to know what you're doing. With the cover off there will be live conductors on the service side of the main breaker, even with it off and those are unfused too.
And can i test whether is (and one other CB which is also blowing far too often) is performing to specs?
Sure. Find every load that's on the breaker. If it's variable, turn it off. If it's fixed, eg incandescent light bulbs you can turn them on. Add up the currents, eg a 100W incandescent bulb will be 100/120v = .8 amps. Take large, known fixed loads, eg hair dryer or small resistance heater to get close to the breaker limit and beyond. Whatever the dryer is rated, the actual will be a bit less. Make sure any heating device is set high enough so that it's full on, constantly. If you're right at the breaker limit it can take some number of minutes to trip. The further beyond, the faster it trips.
this is the original CB box that has been in the flat since the building went up about 40 years ago.
Unclear what that means. Are you saying all that is on the one breaker?
Don't change the 15a to 20a unless you're sure that the circuit uses at least 12g wire. You don't say how big this place is, but 8 breakers isn't much if it's a house. I presume that 15a is for the kitchen counter? Strange they would put 20a everywhere else, but not there. Demands have increased, microwave being a key one, but even back then people had toasters and other small appliances.
This IS a small one bedroom apartment. But now I need to figure out how to put this microwave on either its own breaker or on some minimally utilised one.
Or is it common to add another breaker to the box, if possible without re-wiring the whole place!
Adding a breaker is easy, if there is an empty spot for one. Getting the cable from it to wherever the new receptacle is, that's another story, which totally depends on what's there, ie is their access from an attic, basement, etc. Could be not too bad or real bad. Another option would be to trace out how the existing problem circuit runs and see if there is a convenient point you could intercept it and run a new circuit to and separate it so it's two circuits on two breakers. But first, I'd make sure it's not just a bad breaker.
I see you tube videos on how to test a circuit breaker and change one. But, I see you are in an apartment and would imagine apartment management would be responsible.
Guy at the bank commented that his folks sold their home to move to an apartment near him. They said they do not even need to change a light bulb themselves now.
no, this is a coop with strong regulations on who can be uaed to do ANY electrical work, and i think this will be something for a licensed contractor. The coop will demand it if i try to even ask for the main breaker to be turned off pending making any changes to my box
And IMHO that 15 amp cb is a disaster waiting to happen, what with that much stuff on it!
Too bad. I would hire an electrician myself. Years ago when I bought a generator and had a transfer panel installed they recommended replacement of my whole home panel because of breakers that were prone not to trip. An electrician friend confirmed that he knew of the problem with my panel.
Not sure if you can perhaps save money by following one of the you tube videos to see if you have a bad breaker before hiring an electrician. I think all you need is a test meter.
Well i have a test meter but I spoke to the building super and he said that the wiring behind all the CBs is the same. Which makes sense as the one which keeps tripping controls lots of different wall sockets all around the flat.
i wonder how much improvement I would see if I just change the offending CB from 15 amps to a 20 amp CB? i have no real reason to think there is anything wrong with the CB that keeps tripping, again, it ONLY trips when I leave that 1.5Kw microwave on. I have no real reason to think it isnt just doing its job. Properly.
What with what Clare said, i do accept that this microwave needs its own CB but should a 5 amp increase in capacity suffice to prevent overload?
Not tripping the breaker isn't sufficient -- the breaker was almost certainly sized based on the wiring and the breaker is there to prevent overloading the wiring itself, NOT the loads on the circuit.
14 ga circuit wiring is NOT adequate for a 20A breaker; it would mean pulling a 12 ga wire besides just replacing the breaker.
As Clare said, it _should_ have a dedicated circuit by current Code; but the idea of just putting in a larger breaker is akin to putting a copper penny in the base of the old fuse box...asking for serious trouble.
It would not hurt to replace the breaker with a new 15A one (or even swap this one with another 15A one in the box) just to see if by chance it has become more sensitive with age and consistent tripping. Does happen...
That said, the real answer is to either distribute the load across more existing circuits (without running extension cords all over to do so) or add another circuit or upgrade the existing one--both latter alternatives mean pulling new wire.
Yes, my last posting was designed to take into account your point. Did you not see the bit where I said that the building super said the wiring is the same (gauge) behind all the CBs? I only suggested putting the 20amp cb in place of the 15amp CB BECAUSE the wiring is the same, not because the loads are unknown without a survey!
I can change a CB. I can't distribute the loads more evenly around the whole CB box, and I dont see how anyone could do that without an expensive survey
You don't need to turn off anything more than the main breaker in your box to replace that bad breaker.
While having a circuit that can't support everything that you want to plug into it is obviously an annoyance, it's not a safety issue, that;s what the breaker is there for. And the one in question, if anything, appears to be possibly opening prematurely.
If you're going to play electrician, you should have a clampmeter.
But even without a meter, in less than 5 minutes I could shut off the microwave breaker, locate all the dead outlets and calculate an approximate total circuit load.
And if you decide to install a 20 amp breaker on a 14 gauge wire circuit, please take a video of the resultant fire and post to youtube so we can all enjoy.
As I said previously, you can't change a 15a to 20a unless all the wiring on that circuit is 12 gauge or better, because the wire can't safely handle the higher current. It's worth checking what gauge the wire is, because you say all the other breakers are 20a and this circuit supports a lot of receptacles. Seems odd they'd use 20a on all the rest, not this one. It's possible someone replaced it or the electrician only had a
15a that last day, etc.
i have no real reason to think there is anything wrong with the CB that keeps tripping, again, it ONLY trips when I leave that 1.5Kw microwave on. I have no real reason to think it isnt just doing its job. Properly.
If that's all that's on the circuit, it should not trip, the circuit will support 1800W. If it's tripping, either the microwave pulls more, which seems unlikely or the breaker is bad.
It's not overloaded now. It's just that the microwave will use most of the capacity, leaving little for anything else. Sure, it's desirable to have a receptacle just for the microwave, but most people don't have that, unless it's a built-in one. Most are using a shared kitchen counter receptacle. Your solutions that I see, starting from low cost are:
Find out what else is on that circuit. If it's tripping with just the microwave, high probability the breaker is bad. Verify by putting some other loads that add up on that receptacle, eg hair dryer, electric resistance heaters, etc. Replace breaker
Move other loads on that circuit to another circuit, if possible
Get a smaller microwave
Add another circuit, put in new receptacles or split that existing circuit, etc.
The last one is likely going to get expensive in an apartment, unless the panel is located somewhere that it's easy to run wire between it and the new receptacle or where it can be used to separate the existing circuit, etc. The materials are cheap. The labor of the electrician and probably opening up walls, ceilings, repainting, etc is where it gets expensive.
Well, that's a lucky break. But you need to verify it by checking the wire gauge at the breaker and at all the receptacles on that circuit. If they are all 12g, then you can replace it with a 20a breaker.
DPB wasn't suggesting fiddling with the wiring in the panel, you can't do anything there to distribute loads. He was talking about moving any appliances, lights, etc that are plugged into the problem circuit to another circuit.
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