Hankal wrote:

. Probably the most common is the 4509, which is a 14 volt, 100 watt bulb

I have one and it trips my 20 amp CB.
I know I do not have a short, but maybe my 20 amp CB is weak.
Any comments?

Using Ohm's law, that bulb draws 7.14 amps. Here's what I would do. First, I'd try a
new bulb. If the problem persists, I would remove the bulb and turn the switch on.
a. If the breaker trips, you have a short in either the switch, the socket, or the
wiring between the two. I would then disconnect the switch from the wiring to the
light and try again. If the breaker pops, the problem is in the switch.
b. If the breaker does not trip in the first test, then hook up a pair of test wires
to the bulb. Disconnect the wire that runs from the breaker to the switch at the
breaker. Then run one of the test wires to ground and touch the other to the breaker
output pole. If the breaker trips, it's the breaker.

George Patterson
None of us is as dumb as all of us.