Phantom Flickering

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 problem?
Ron
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

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 proactive.
hth,
tom @ www.WorkAtHomePlans.com

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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 short.
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 contact.
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 connections.
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 circuit.
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.
TKM
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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 condition dangerous?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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 heat/smoke/fire.
TKM
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Anonymous wrote:

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 possible.
Be safe, have it professionally checked if you are not sure what all that means.
--
Joseph Meehan

Dia duit
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Anonymous wrote:

Andy replies:
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
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.