Question about Rheostats and Watts/Volts

Kiljosh · 11-21-11, 04:56 PM

Hi, so I don't want to burn my house down.

Today I went and got a replacement bulb for my BP's 55gal tank. The hotside needed two lamps to get it up to 90, I've been making due with a bright heat bulb and an infared bulb. When at the store I couldn't remember the max rating for the fixture with the bright bulb in it. I got a 75watt infared bulb and brought it home to find the fixture is rated for 60watts.

I have been told the ratings are for the safety of the fixture and a higher wattage bulb than it's rated for can melt the insulation on the wires inside. So it sounds like the biggest issue is heat.

So my question is, can I use the 75watt bulb in the 60watt fixture if I hook it to a Rheostat and turn it down low enough where I can get the temps I need without having the 75w bulb run at full power and possibly melting stuff, causing an arc, and burning my house down?

Also, for future knowledge; when using a Rheostat does it change a device's incoming voltage, wattage, or both. I'm no electrician and I apologize if this question is semi-stupid.

Thanks guys.

infernalis · 11-21-11, 05:09 PM

Rheostats are a resistor that is variable.

However a dimmer is not. A dimmer chops off the peaks of the voltage on the AC sine wave.

Potentiometer - Wikipedia, the free encyclopedia

I would personally get ceramic sockets, 60 watt sockets are plastic.