Most every switch in my home and at work are fully silent. I have run into a batch of 25 year old switches that are strictly mechanical. Is it common to be able to hear a slight crackle when operating these swicthes? The owner of the home tells me his family room lights when out but came back on by themselves. Breaker appears good so I checked the switches and that's when I noticed a crackle when operating the switches slowly. Is that normal? Thanks, Bob

With a 25 yr old switch, even a new one, tarnish has possibly built up on the contacts and they are not allowing current to flow through smoothly. Unlees there is some reason to use them, regular SP switches are .50 at HD and Lowe's.

Bob,
Suggest that you check to see if the "Quick Connect" holes in the back of the switches and outlets have been used as the cause of the intermittent light failure. Not unusual to hear the arcing that occurs when a switch is opened or closed, if you listen closely.

The "Quick Connect" holes are notorious for bad connections after a period.

Toggle switches all have springs to open the contacts fast to eliminate the arcing.

The springs in older switches will wear out and allow the contacts to open slow. In a home, the power is low enough usually not to be a hazard, just after a while the contact do burn and add to the air gap, and usually fail without any great damage other than the switch.

Back in the old days, esp in industrial plants, there were what is call Isolation Switches, those open blade switches, same as seen in Frankenstein movies. These switches, per Code:

404.13 Knife Switches.
(A) Isolating Switches. Knife switches rated at over 1200 amperes at 250 volts or less, and at over 600 amperes at 251 to 600 volts, shall be used only as isolating switches and shall not be opened under load.

Had signs warning Do not Open Under Load. What you see in the movies with the arcing is because a human cannot open the switch fast enough to prevent the arcing.

The arcing is due to the electricity is conducting through the air, moist air the better, and ionizing the air to continue the flow as much as possible, until the gap is great enough.

Here is a video of a slow moving switch and the result of high power and/or load to illustrate what is happening inside the switch at home, at much lower energy level.

And this is an excellent reason also;

Quote:

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Originally Posted by hkstroud

Bob,
Suggest that you check to see if the "Quick Connect" holes in the back of the switches and outlets have been used as the cause of the intermittent light failure. Not unusual to hear the arcing that occurs when a switch is opened or closed, if you listen closely.

The "Quick Connect" holes are notorious for bad connections after a period of time.

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