If your lamp is a 4522 then it is a PAR46 bulb, 13 volts 250 watts
5.75 inch dia with a rated life of 25 hours. 250w/13v = 19.23 amps
not counting the initial surge of about 5 times the rated current. A
20 amp breaker is too small to power this lamp.
You can get lamps in this same size glass housing from 35 to 450
watts.

A 4552 lamp is a 250 watt 28 volt PAR64 lamp , 8 inch dia which is the
number you listed first This lamp will draw about 9 amps which is
about correct for a 20 amp breaker.

I suspect someone installed the wrong lamp in your aircraft. Many
14volt 172's use a par36, 4509 lamp which is rated at 13 volts, 100
watts, 7.7amps.

You need to look up in the parts list for the aircraft the correct
part number of the lamp.

On 21 Aug 2004 23:36:14 GMT, (Hankal) wrote:

Nobody looks it up. The 4522 lamp is usually used in a swing-down lamp.

The landing lamp is a GE 4522.

If I posted different, then it is my error and I appologize.
Hank