I’ve been noticing something odd about a couple of lightswitch plates in our house–both dimmer switches. They feel warm. Not hot, but definitely warm (about 100 F), and the other lightswitches don’t. Is this bad? It is a sign of wires getting old or something, or is it nothing at all?
It’s OK for Dimmers to feel warm. They’re not 100% efficient.
In fact the switching device (most likely a TRIAC) is usually mounted to the underside of the metal faceplate to help it dissipate heat. That’s what you’re feeling. If it’s getting warm while the switch is off then there might be danger, mom.
OK, thanks. I’ll check them when they’ve been off for a while.
Yep, it’s totally normal for a dimmer switch. A dimmer switch routes the current through a certain amount of resistor coil depending on where the knob is at. This increases the resistance and reduces the amount of current getting to the lightbulb. The way the resistor coil works is like a small heating element, and since some of the energy is used to make heat, less gets to the light bulb, with the results of romantic mood lighting.
Yep, it’s totally normal for a dimmer switch. A dimmer switch routes the current through a certain amount of resistor coil depending on where the knob is at. This increases the resistance and reduces the amount of current getting to the lightbulb. The resistor coil works like a small heating element, and since some of the energy is used to make heat, less gets to the light bulb, with the results of romantic mood lighting.
Nowadays, most dimmers are solid state. As previously noted, these generally use some sort of SCR to chop the voltage waveform to control the amount of power delivered to the bulb, rather than use a resistive element.
The switchplates were indeed cold when not in use. So I guess we’re not going to wake up one night and discover that we’re all burned and corpsified from an electrical fire in the walls. Thanks all.
Woah … I posted “use a dimmer with no moving parts”, and the post was deleted.