Buzzing From New Dimmer Swith

Old 09-10-00, 07:37 PM
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I changed a wall outlet on/off swith that controls a 4-bulb vanity light in the bathroom to a dimmer switch. It was a simple straightforward job, BUT this is a hissing/buzzing at the swith now. I have the disconnected breaker switched off until I can figure out what's wrong.

Anyone know why this might be and/or how to fix it? Is it due to a loose connection?

PS: Sorry if this topic has been addressed, I search the Forum for answers/suggs, but had no success. Please help.
Old 09-10-00, 10:10 PM
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Could be a loose connection, or it could be a faulty switch. If you can't find any problems with the connections, try another switch.
Old 09-12-00, 10:19 AM
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A dimmer switch will sometimes have a humm in is caused by the resister holding a load. This humm is most often experienced when you approach nearer to the maximum capacity of your dimmer.

You say that you have four bulbs on that dimmer. Most likely if you have a residential light duty dimmer switch, it will be 600 watt rated. If you have four one hundred what bulbs in that fixture you are approaching the maximum capacity of your dimmer. I do not see a hazard but it may be an annoyance.

To confirm that it is a humm due to the vibration of the resister in your dimmer, turn you dimmer to full brightness. The humming should lessen the closer to full brightness you go and increase the closer to maximum dimness you get.

This is also sometimes experienced in the light bulbs that is controlled by a dimmer. The filiment of you bult [fine wire that gets hot to produce light in the bulb] will tend to vibrate.

These vibrations tend to coincide with the frequency of your a/c type current. 60 times a second in the reversal of electricity tends to produce the vibration. Now the lower the voltage becomes the more pronounced the hum becomes because of the hertz cycle of your a/c.

Watch that you dimmer does not get too hot to hold your hand on it. Warm is ok. Hot is something to worry about. If your dimmer gets hot to the touch make it feel like burning the skin or making it uncomfortable to touch by bare skin, then change the dimmer to a 1000 watt dimmer that has cooling fins on it and it should eliminate the hum and correct the overheating.

Good luck

Old 09-12-00, 02:56 PM
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If the switch is defective, then so it is. The question that automatically comes to my mind is: Was this a cheap dimmer switch in the $3-$5 range? I rarly install cheap dimmer switches because they do not have components that filter out some of the anoying noise produced from the lightbulb filiments very well.
Another avoidance to make is Lutron. Lutron's electrical supplies are not very good compared to other manufactures such as Leviton, Motorola, Osram Sylvania, Eagle Electric, General Electric, or Bryant/Hubbell.

$8-$13 is a reasonable price to pay for good single pole 600W standard grade dimmer switches.
I hope my advice for choosing a better dimmer switch helps!
Old 09-13-00, 07:07 AM
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Thank you wgoodrich, I think I had a dimmer swith that had gotten too hot. I replaced it & now everything is working properly. You
guys really know alot about home projects, thanks for sharing your extensive knowledge with me.


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