Ask LiveJournal Electrician: light fixture maximum wattage?

[randomness]

We have this old swing-arm lamp that takes three position bulbs. The socket is stamped 250W 250V, but I can't tell if it's just describing the socket or if the wiring in the lamp itself is rated for 250W.

Most modern swing-arm lamps I've seen have a tag that says they're limited to 150W. I figured I'd ask around before I put a 250 watt bulb in it and started a fire. :)

Anyone have any thoughts?

Comments

[awfief.livejournal.com]

You can't start a fire with a higher watt bulb. If the socket sends 150W to a 250W bulb, you get a 150W light. That's how things like "dimmer switches" work -- they send less power to the bulb. The problem is you're going to start a fire because a 250W bulb is incredibly hot at full power. Can you even find a household 250W bulb that's not a flood light?

[r-ness.livejournal.com]

Actually, I was concerned about drawing more power through the wiring of the lamp. There are

There are 300W bulbs available for normal as well as mogul bases in the standard shape. There are a couple of 100/200/300W three way bulbs for both size sockets, although as they're too high wattage for the socket I'm not really considering them. There are also 50/200/250W three way bulbs available for standard screw-in bases, which are the bulbs I'm looking at.

Heat isn't a problem right now, actually; the fixture is base-down and if it helps to heat the room it's all to the good. :)

If there were a three-way CF that put out 2500-3000 lumens at max output, that would be nice, and it would probably be less than 50W at max output--I found a 60W single power that does 4000 lumens or so--but there isn't.

[gravitrue.livejournal.com]

Wires are resistors. They waste some of the power that goes through them as heat. The thinner the wire, the more it will heat up given the same amount of power going through it. A heavy load will try to suck more power through. Suck too much power through and things can catch fire, or simply melt off the insulation and cause shock hazards.
A standard light socket does not magically stop power at some wattage cutoff, it starts heating up. Of course, it might start melting from the bulb's heat first, which also isn't going to improve its safety any.

A dimmer, on the other hand, does magically stop the power at a given cutoff; most dimmers work by switching the light on and off really fast.