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ScottyMac
Jan 5, 2009, 08:18 AM
I have one outlet dedicated to a 15 AMP breaker in an older house( 35 years) that I have a 1000 watt microwave and a 80 watt water cooler plugged into but it keeps on tripping.

I have replaced the breaker with a new one and it still trips about once a week when I start up the microwave. I am new to this but from what I read here that circuit should handle about 1800 watts. Is there any other possible solutions?


Thanks

Scott

StaticFX
Jan 5, 2009, 08:26 AM
You need to check the AMP draw on the microwave & water cooler... Watts isn't as important.

I think the avg AMPs is 9 or 10 but some microwaves can pull 15amp.

Someone else will need to verify this, but cant you just up the breaker to a 20 amp?

codyman144
Jan 5, 2009, 01:33 PM
Watts is important... and you are right that circuit should be able to handle 1800 watts (120V*15Amps=1800 Watts).

No you CANNOT just up the breaker to 20 Amp… Only if all the wires on the circuit are 12 AWG and the outlets are all rated at 20Amp can you do this. And chances are if your breaker is 15 Amp that is because that is the max your wires can take (14 AWG). If you put a 20 amp breaker on a 14 AWG wire you are creating a big fire hazard and violating code big time.

What I would do is check the size of your wires. If and only if they can be upped to 20 Amp do so. Sounds like there is more on this circuit than the microwave (like some lights etc) and that is what is causing your breaker to trip. If you find that you have 14 AWG wire in the walls consider changing it to 12 AWG and installing a new 20 Amp breaker. In new code you are required to have two separate 20 Amp circuits at your Kitchen counter. This is because these new appliances use more power than before.

KISS
Jan 5, 2009, 02:06 PM
The magnatron in your microwave could be aging and poor heating and breaker blowing may be a sign. How old is the microwave?

stanfortyman
Jan 5, 2009, 03:25 PM
I bet there is simply more on this circuit than you know/think.

ScottyMac
Jan 5, 2009, 03:43 PM
Thanks for all the tips.. I checked and this is the only outlet on this breaker, nothing else goes off(lights/appliances etc) when it trips. The microwave is about 10 years old now.

Based on the age of the house an electrician I called today thought I would have older wiring that could not handle a 20 AMP breaker due to fire hazard.

Would getting a microwave with 700 or 800 watt rating help or make no difference? None of the specs on the microwave tell me the AMP rating just watts.

KISS
Jan 5, 2009, 04:29 PM
Perform Microwave test #3 in this link:

http://www.ctahr.hawaii.edu/new/Pamphlets/MicrowaveCookingFnl-3.pdf

andrewc24301
Jan 5, 2009, 04:54 PM
It is recommended not to exceed 80% of the circuit breakers capacity. So about 12 amps would about be your limit on a 15 amp breakers.

Just something to keep in mind.

Stratmando
Jan 5, 2009, 07:23 PM
If you have an Amprobe, you could connect on wire from that breaker, It may be drawing something already, take note, heat something and see what the additional current it is drawing. If drawing 17 amps and it trips, breaker is likely good, if you see it tripping at 12? Amps, the breaker is bad or loose on the buss or loose wire on Breaker.

StaticFX
Jan 8, 2009, 06:06 AM
Watts is important... and you are right that circuit should be able to handle 1800 watts (120V*15Amps=1800 Watts).

No you CANNOT just up the breaker to 20 Ampů Only if all the wires on the circuit are 12 AWG and the outlets are all rated at 20Amp can you do this. And chances are if your breaker is 15 Amp that is because that is the max your wires can take (14 AWG). If you put a 20 amp breaker on a 14 AWG wire you are creating a big fire hazard and violating code big time.

What I would do is check the size of your wires. If and only if they can be upped to 20 Amp go ahead and do so. Sounds like there is more on this circuit than the microwave (like some lights etc) and that is what is causing your breaker to trip. If you find that you have 14 AWG wire in the walls consider changing it to 12 AWG and installing a new 20 Amp breaker. In new code you are required to have two separate 20 Amp circuits at your Kitchen counter. This is because these new appliances use more power than before.

Thanks codyman - learned something new! I always thought it was amps that was most important. That formula is handy too!