Lighting and shooting at home
Posted 10 October 2007 - 12:59 PM
But I don't know anything about the power requirements/restrictions/limitations of domestic power.
Say if i want to put up 2 arri650w and 1 arri350w ,will i start a fire??
i guess my real question is where can i find information (book/site) about the elctrical knowledge tha need for lighting.
if my question was vague,let me know so i can rephrase it.
Posted 10 October 2007 - 03:42 PM
I always have my three 500 watt lights plugged into my house circuits with no ill effects.
Edited by Zamir Merali, 10 October 2007 - 03:45 PM.
Posted 10 October 2007 - 04:00 PM
The simple rule in the U.S. is to just make 1 amp = 100 watts, even though you can get more than 100 watts out of one amp. That gives you a little leeway. So for a 20 amp household circuit, generally a 2K tungsten or a 1200w HMI are the biggest lights you can plug in, or multiple lights that add up to 2K (2000 watts). But again, that's per circuit, not per outlet. And watch out for other things drawing power on the same circuit, like the refrigerator.
If you want to be thorough, go to your circuit breaker box and turn off everything except one circuit, then go around the house and plug a lamp into each outlet until you find (and label, with some tape) which outlets use the same circuit, and how many amps are on that circuit.
Posted 10 October 2007 - 06:39 PM
The normal power output for a Canadian or US home on a single circuit is 15 amps at 120 volts. 15 * 120 is 3000 watts. This doesn't mean you can put 3000 watts of lights in a circuit though because a light draws considerably more power when it first turns on. I would say you can put about 2000 watts of light on a circuit and your breaker wont trip.
15 x 120 = 1800, not 3000. In general a 2K or 1.2K HMI is the largest you'll put on a single household 20amp circuit; a 15amp circuit won't hold a 2K for very long. It's easiest to use the "paper amps" method of rounding down to 100 volts; divide your wattage by 100 and that's how many amps you'll need.
Tungsten lights don't draw more power on startup the way that HMI's do. It's true that it takes more power to heat up the filament to operating temperature, but it's really only an issue with large units, not so much 650's and 1k's. You're actually more likely to trip the circuit after the lights have been on for awhile and the circuit heats up, especially with the older type circuit breakers.