Microwave blows Circuit breaker randomly, has new circuit breaker in main box. I think the microwave is causeing this.
Other day the microswave shut down for about a minute after
it was running, appeared to reset itself and now running ok.
Microwave has two high power diodes, this problem usually occurs when the diode which one end is grounded with the steel body of the oven becomes faulty and starts drawing more current, so you have to replace that one with the same type, replacement is very simple as no soldering requires, it has a clamp on one end and nut bolt arrangement with the grounded end, this component can easily be found near the outo transformer of the oven. Also if the oven stops heating, check this component it may be worn out, drawing no current for magnetron.
One thing to check is that all the wire connections at the breaker are really tight. Also check the wiring connections behind the built-in microwave. I have had several cases of loose wiring causing breakers to trip due to the reduced ability of the connection to carry the rated amperage flow when the wire is loose.
If it isn't a built-in, try temporarily placing it somewhere so it can plug in on another circuit where there is little or no load for a test.
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Re: Jenn-air model jmc7000
First of all, a microwave should be on its own circuit breaker.
It's very common for a breaker to blow if it has a microwave and a fridge, etc., on the same circuit.
The fuse is usually rated at a lower current than the breaker, so it's very unusual for a microwave to blow a breaker without blowing the fuse.
Once a breaker blows a few times, it should really be replaced. It has a bimetallic element which will experience metal fatigue and become inaccurate. This could be the problem, too.
The breaker for a microwave should be no less than 15 amps, and 20-30 is better.
If you or a friend has a a clamp-on ammeter, you can monitor the current the microwave consumes. This can be helpful in diagnosis.
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Generally microwaves should be on their own breaker. Hard wired ones are required to be by code.
If yours has a plug - make sure the plug is original with the unit, not added later or spliced onto hard-wired power leads.
Plug into and outlet rated 15A as the only thing on a 15A branch circuit and try again. If it still trips, try a 20A line and circuit. If it trips that, trash the microwave and buy a new one. Nothing is meant to be repaired inside.
I have a hard time believing that the home's main breaker is tripping instead of the branch circuit breaker that feeds the microwave. I suspect it is really just a difference in terms. You should disconnect it and try using in another outlet - preferably one on a different circuit if possible. If the breaker continues to trip; this appliance should be disconnected and either be discarded, repaired or replaced before using again.
If the microwave works as expected (on a different circuit), it may indicate the original circuit is overloaded. Microwave overs are supposed to be installed on a dedicated circuit. This means only one outlet is on the circuit - no other loads (lights, appliances, etc.) are permitted on this circuit. A microwave typically requires 10 Amps or more when on "high" and will require a significant portion of the power supplied by a 15 or 20 amp circuit breaker. There is little unused to power much of anything else. If other appliances go out when the microwave trips the circuit breaker, you should contact an electrician to have a dedicated outlet installed for the microwave.
your power transformer for the magnetron could have a shorted primary power winding,the door safety interlock switch could be mis-adjusted,this normally blows the internal unit fuse,a shorted high voltage capacitor,or diode,a bare wire inside the unit,more than the microwave on that circuit or a weak circuit breaker in the house power panel
Is it just the microwave or are there other things riunning on the same circuit? Electric jug, dishwasher. TV
If nothing else is on at the same time and the Mwave trips then it time to get a new Mwave. But have an electrician put in an additional circuit to lessen the load on that one circuit. Cost about $70-100 depending on distant of meterbox to the main plug.
I've had this problem twice with our microwave. The hint to where the problem lies is that the breaker blows when you open the door at times. Inside the microwave are three microswitches; primary and secondary interlock micro switches and an Interlock Monitor switch. The switches are supposed to shut down the microwave if it is running and the door is opened. But, I've found the upper primary switch can stick internal at times and when the door is opened the stuck switch will, because of the way it is wired as a safety switch, cause either the fuse or possibly the main circuit breaker for the oven to pop. The reason the stuck switch blows the breaker or fuse is when the door is opened the interlock switch will cause the neutral wire from the AC power to be applied to the Upper Primary Interlock switch which normally should be open when the door is opened, but if the switch is intermittent or the contacts weld themselves shut the neutral line is connected direct to the "hot" side of the power line through the fuse and thermostat. The first time my microwave failed the switch had melted the contacts together inside the switch and the second time the switch became intermittent and would blow the breaker to the over ever so often. I suspected the switch the second time this happened and utilizing an ohm meter I checked the switch several times by opening and closing the door and once in a while it would remain closed instead of opening when the door was opened. Of course while trouble shooting the power cord to the microwave must be disconnected and use all safety precautions when working around the high voltage areas inside the microwave. I wrote Jenn-Air about the bad switch and the way it is wired into the circuit, but never received any acknowledgement. I suspect these microswitches are under rated for the amount of current that passes through the switch, thus they overheat and eventually arc the contacts together. I hope this helps explain the intermittent problem and could explain many of the intermittent blown fuse problems I see in these internet help sessions
The problem may not have anything to do with the magnetron.
It is a device that uses DC for operation and to supply that, there is one or more heavy diodes that are more likely to fail first.
Have also seen the transformers fail occasionally too.
Frankly, it may be time to dispose of it since you will likely be billed for the repair if the magnetron is not at fault and once they have it, you don't know if the truth is being told or not.
Another possibility is a circuit breaker on its way to the grave.
If you care to go to the trouble, you might shut down the main breaker in the breaker box, swap the tripping breaker with another of the same rating and try the microwave one more time.
The surge current the microwave draws is probably a good bit higher than the hair dryer and might be enough to trip an aged breaker.
Normally when the circuit breaker blows, it a bad door switch or door switch mount.
If you or a friend decide to look into it, we have critical safety information, info on door switch diagnosis and replacement, and
disassembly information at our site, and our link is at our listing here on FixYa: http://tinyurl.com/yzjozk
You can usually find helpful exploded view diagrams and order parts by entering your full model number here: http://tinyurl.com/gv383
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