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When to Use a Generator?


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#1 Matthew B Clark

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Posted 17 April 2012 - 01:09 PM

Please pardon my ignorance. but when do I know to use a generator for my lighting kit? I am about to pick up a small lighting kit (300/650/650 Watt fresnel package, possibly another 1000 Watt)

I'm wondering "at what point" I need to really worry about electrical problems. Like either frying my lights and/or when exactly DO they draw so much power that the walls burst into flames? Or is that all nonsense altogether? I have no electrical knowledge at all. Frankly it scares me to death. I just want to be safe...and run a simple light kit for a small 16mm film project without blowing the various locations up in the process. Baby steps.

Thanks for the help guys.

-Matt
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#2 Brian Drysdale

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Posted 17 April 2012 - 01:24 PM

The maximum wattage you can draw depends on the power arrangements in the country where you're filming.

With the type of lights you've mentioned you should be fine most domestic environments, but you'll probably have more limitations in 120V counties compared to say the UK. If in doubt spread the load over a number of circuits.

If you give the country where you're filming, people can give you more precise advice.
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#3 Travis Gray

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Posted 17 April 2012 - 02:01 PM

In the US, I've done small to medium light setups (relative term I guess... a mixture between about 16 400w lights and a handful of 575w, all spread out among circuits in the building we were working in. Did our calculations just to make sure we knew where the circuits were and what service the breakers were. Then spread out from there.
Have also done larger gigs where we tied into the building power with another breakout box. But these were all within limitations of the building's power.

Outside gigs and ones so large that they exceeded the building's power we've pulled in generators, but I think with your package, with calculations and planning, you should be able to use the building no problem.

As far as burning wires and such too, make sure you're using the right gauges for your lights too. Too thin and it won't be able to properly handle the power being drawn.
http://www.electrica...cable-and-wire/


This will be a help too: http://www.supercirc...-Amps-Converter
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#4 Matthew B Clark

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Posted 17 April 2012 - 02:03 PM

Thanks Brian. Edit: and Travis! I am located in the USA. I'm looking at these types of Arri knock-offs (CineLight, etc.) that are all over eBay.

http://www.ebay.com/...=item1c25f831d6

Will something like that, plugged into USA outlets burn a hole in my walls (or lights)?! Also, I'm wondering if I'm going to need something bigger, like a 1K. Using as a general purpose kit to light interiors for a variety of scenes.

Edited by Matthew B Clark, 17 April 2012 - 02:04 PM.

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#5 Travis Gray

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Posted 17 April 2012 - 02:10 PM

Thanks Brian. Edit: and Travis! I am located in the USA. I'm looking at these types of Arri knock-offs (CineLight, etc.) that are all over eBay.

http://www.ebay.com/...=item1c25f831d6

Will something like that, plugged into USA outlets burn a hole in my walls (or lights)?! Also, I'm wondering if I'm going to need something bigger, like a 1K. Using as a general purpose kit to light interiors for a variety of scenes.



A general rule of thumb I worked with when doing stage lighting was a quick calculation of 100 volts. So, 1000w going into 100v was 10amps. And we were working with mostly 20amp services. So, 2 1k lights. Obviously if you're working with 120v, you can push more, but we would stay under just to have the room.

If it's a house, I would just double check to make sure the wiring is fairly sturdy, depending on the age of the house, and you should be able to get at least 1 1k light on a circuit, assuming it's a 15amp service. And make sure you know what else is going to be on that circuit. If someone's charging a cell phone, it would more than likely be fine, but if someone's using a blow-dryer, something's going to pop.


As far as things blowing up and creating holes, I was never quite sure on how that happened, so I'd have to defer to someone else haha. I think it has to do with wire gauges and how sturdy the connections are. I have wired edison ends improperly before and wires have touched and melted the ends, so that's something to be aware of too.
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#6 Matthew B Clark

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Posted 17 April 2012 - 02:22 PM

Thanks a ton, again. So a standard house/building in the US is typically 120 Volts? One big fat circuit? Or many inside a single house (and I assume I'd have to ask for electrical plans etc./possibly consult an electrician?)

Or can I just safely lug a small 3-point lighting kit (a few 650's say) and just jam them into the walls and roll?
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#7 Travis Gray

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Posted 17 April 2012 - 02:27 PM

It depends. I can't remember how many my last house had, but I know my first apartment had a grand total of 4 circuits. 3 15-amp, 1 20.

They might have been 10-amp. It was an old apartment.

Find the circuit breaker box and check. The switches will have a number on them as to how much they can handle.
And more than likely they are 120v. There are testers you can buy for these things. (voltmeters, and breaker identifiers... you plug them into a socket and check the breakers to see where it corresponds)

If you have a completely clear 15-amp circuit, you could get all 3 650w lights on there, but I would probably play it safe if I didn't know the location that well and spread it to 2 lights on one, and the last on it's own circuit. And then maybe the 1k on a third circuit.
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#8 Matthew B Clark

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Posted 17 April 2012 - 02:38 PM

Cinematography.com....gettin things DONE! Thank you for the info. I'll do some poking around the breaker box and find out what this place has.

So I assume for outdoor shoots, and weird spots like caves, gothic castles, the woods, or inside the back of a van...you need a generator. Doh!
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#9 Travis Gray

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Posted 17 April 2012 - 03:09 PM

So I assume for outdoor shoots, and weird spots like caves, gothic castles, the woods, or inside the back of a van...you need a generator. Doh!


Indeed.

..UNLESS... for the van, you get a battery conversion kit. When I worked at the stage lighting place, we were hired for a weird protest event where they wanted a searchlight effect. No power. No money for generator. We bought some thing that hooked up to the car battery (chevy cargo van) and we left it running and powered a 575w lamp. We thankfully bought two, the first one didn't work, so we had a backup. I forgot how it worked, but it did exist.

So you could probably even go with that and run a couple LED lights off of it. But, then, back of a van, with it running... fumes...
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