Microwave causes lights to dim


Old 06-07-07, 07:31 AM
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Join Date: Jun 2007
Posts: 5
Microwave causes lights to dim

Just bought a new house. When the microwave is in defrost mode it momentarily causes the lights in the kitchen to dim, specifically when the microwave draws a heavy load. The dishwasher can also cause the same problem when first starting the electric motor. With my limited knowledge of home wiring it seems to me that there is simply too much on that leg. In the kitchen we have 2 hanging lamps, refrigerator, oven, dw, microwave, disposal and of course some wall outlets. Is it possible (advisable?) to split that 1 leg into 2 and add another breaker at the panel? What would be the recommended course of action? I don't mind paying an electrician but would prefer to know a little bit about what I should expect first. Thanks!
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Old 06-07-07, 09:17 AM
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Join Date: Jun 2007
Posts: 5
Well I seem to have found the answers already here in this forum. Looks like I should run a new 20 amp circuit dedicated to the mw. It was probably just a range hood originally and was replaced w/ a mw/hood.
Old 06-07-07, 09:36 AM
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You're on the right track. Ideally the dishwasher should also have a dedicate circuit or share a circuit between the disposal and DW.

All the appliances you listed should have at least 4 circuits, and probably more like 6 or 7 based on modern code. If everything in the kitchen is on only one circuit, then you certainly need to fix that. Depending on the age of your home, it's likely that 2 or 3 circuits feed the kitchen which is okay, but pushing the limits as you have found out.
Old 06-07-07, 09:42 AM
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You're correct. A over-the-range microwave should be on its own, dedicated, 20A circuit. And as ipbooks mentioned, you may want to consider some additional circuits while you're at it.

Just as a minor detail, in your original post you mentioned "legs". You're talking about adding a new circuit or two. The "legs" refer to the main feed to the house, where you have 2 legs that are split into multiple circuits. Minor detail, but you may end up confusing yourself or someone else in the future.

Good luck!
Old 06-19-07, 01:49 PM
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Join Date: Jun 2007
Posts: 5
That's what I needed to know.

Thanks again guys!

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