Lately I've been noticing that when the microwave cycles on half-power
setting, the lights in the kitchen and every where else on that
particular circuit flickers perilously along with it. Sometimes just
turning on the kitchen light makes the other room lights flicker.
I suspect a short, but since nothing ever trips a circuit breaker, it
doesn't seem to be anything I can definitely put my finger on to test or
repair. Does anybody have any suggestions for tracking down this
Are they dimming and then growing brighter, or just shutting off and
on? Are they florencent?
A short should have tripped yoru breaker, so let's hope your breaker
first is working ok. If you think you have shorting or arcing
problems, I would immediatly get professional electrician to check.
Cheaper to have a sevice call than a fire. Don't PANIC, just be
tom @ www.WorkAtHomePlans.com
If by "flickers" you mean that the lights actually go on and off, not just
dim, then it's likely that you have a loose connection somewhere, not a
If you aren't comfortable working around electricity, call a professional
electrician right away. A loose connection can generate an electrical arc
(very hot) and cause a fire.
A loose connection could be anywhere in the branch circuit. The microwave
is a fair power load; so when it comes on, the current flowing in the
circuit probably stresses a connection somewhere and there's intermittent
You can check a few things. Kill the main power and look at the branch
circuit breaker for the microwave oven (you will have to take the cover off
the CB panel). Be careful. There is still power in the box by the main
breaker. Check the circuit breaker to be sure it's tight in the panel and
check especially the screw that connects the black or red branch circuit
wiring to the breaker. Check the white wire (neutral) for that circuit too.
If you are lucky, you may find a loose wire or melted insulation or
blackening that indicates arcing.
If the connections in the panel look good, check the outlet that feeds the
microwave. Again, make sure the power is off. Take off the wall plate and
look at the wiring that feeds the otulet. Take out the screws that hold the
outlet in place, pull the outlet out of the box and check the tightness of
the outlet screws. If there are other connections in the box (wires
fastened together with wire nuts), check those too. Put everything back
very carefully and watch that any bare (ground) wires don't touch any other
Those are the easy and obvious checks. Less likely would be an electrical
problem inside the microwave; but you can check that by running a
heavy-dluty extension cord to the microwave and plugging that into another
Again, if you don't have a healthy respect for electricity and don't
understand what you're doing, have an electrician do the work.
I always thought it was the microwave, but before I could get the chance
to do much of anything, I went to turn on the kitchen lights and that
went dead along with all the other lights on that circuit. I checked the
breakers and like before, none of them have tripped.
I can't get an electrician until Monday, so I turned off all of the
other lights on the circuit, but I thought that if there's an overload
condition the circuit breakers would trip. Is this intermediate
Switch the breaker for that circuit to off until the electrician can check
the circuit. If you leave it energized, there's a chance that the
intermittent connection, that is apparently the problem, could arc and cause
There are several possible problems. A number of them could be very
dangerous (generally fire danger).
If the home about 40 - 60 years old it may have aluminum wire and the
whole wiring system should be considered suspect.
A floating neutral, poor connection. undersized wiring and others are
Be safe, have it professionally checked if you are not sure what all
Bear in mind that when your microwave is on the 50% setting, it
is going FULL ON 50% of the time and MOSTLY OFF for 50% of the time.
If it is a big mother microwave, this can be a 10 to 15 ampere change.
An experiment would be to turn on the lights, then turn on the
microwave to full power. If there is a single flicker when you
energize the microwave, and a single flicker when you turn it off,
you are certain of the source and the reason. When the mother
microwave turns to "ON, FULL POWER", there is a big current draw.
Much like when you turn on your vacuum cleaner.....
Go to your breaker box and tighten the connections to the breaker
that feeds the microwave. Then tighten all the connections on the
neutral bar. If these connections are loose, this should clear up
the problem. However, usually the mother microwave has it's own
circuit breaker and it doesn't usually feed other circuits......
at least in newer construction.
I hope this helps. Wear gloves. And if you are really scared around
the electrical box, have your brother-in-law do it for you......
Andy in Eureka
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