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Todd Terry
Power distribution
on Aug 3, 2008 at 8:24:36 pm

Hi gang... (cross posting in cinematography, hope no one minds)...

I need some help from those of you with more electrical knowledge than me (which won't be hard to find, I'm no electrician)...

I need to figure out an easier way to split power distribution to instruments.

Here's the deal... it seems that lately we are tripping breakers left and right when shooting on location. For smaller shoots we usually travel with a few tungsten instruments, but lately we have been shooting in some larger venues that require us to break out the daylight gear. For those, we usually use two 1200w HMIs, one 800w Joker-Bug, and a few smaller instruments.

It seems that no matter how careful we are, and how much we try to spread out the power, we end up overloading a circuit and tripping a breaker somewhere.

Now, I know the right way to do this... carefully plan the location, find where all the outlets are, get with the building engineers to determine where all the breaker boxes are and what breaker goes where, etc etc. But in practicality we usually can't do that. These shoots are very run-n-gun.

Some examples....

Once this week when shooting promos in a TV studio, even though were were told where to juice from, one single 1200w HMI tripped a breaker that shut down all the computers in their weather department. Not good. It took them fifteen minutes just to find an engineer who even knew where the breaker box was.

The next day we were shooting a political commercial in an old church, and kept tripping breakers even though we were snaking cable and running instruments to outlets on multiple floors. In a 100-year-old building you can't be sure that the wiring plot makes any sense. No one from the church working that day knew where their breakers were either... we just had to search until we finally found the boxes.

Couple of weeks ago in a car dealer's showroom we tripped a breaker that shut down computers in the accounting department in a completely different part of the building. Who is wiring these places?

And yes, these are very low-budget shoots so we can't afford a genny.

So... speaking just off the top of my head... is there such a thing as some kind of an electrical gadget that one could, say, plug into a regular Edison outlet and it show you what kind of load is already on that circuit?

Or any other solutions that anyone has to suggest?

Thanks,


T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com






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Michael Palmer
Re: Power distribution
on Aug 4, 2008 at 3:46:22 am

Todd,
Circuit breakers for wall plugs are either 15 or 20 amps, and most new buildings are 20 amps. I never believe a plug in any room is isolated to that room and can supply the maximum value of the breaker. Every building is different and knowing where to find dedicated circuits can help, Start with the kitchen as there should be at least 2 circuits in there, 1 for the garbage disposal underneath the counter and one for the Microwave, electrical rooms and service outlets near AC units outside can be a great source for dedicated circuits. Remember the longer the extension cord the more line lose you will have that creates more amps.If you are going to use more than one lamp on an extension cord then make sure you use 12/2 cable and 20 amp rated adapters and not those orange cords from Target. I would rate your 1200 watt HMI @ 12 amps and the 800 watt joker @ 8 amps inflating value to what the lamp actually needs to ensure against popping breakers. You should be able to run both of these lamps from 1-20 amp breaker provided you are completely sure nothing else is on this circuit breaker. Honda makes some beautiful portable inverter generators including a new
Ultra Quiet 6500 watt 120/240 inverter generator, http://www.hondapowerequipment.com/products/modeldetail.aspx?page=modeldeta...

The bigger the lighting setup the more power you are going to need. This Honda is on my list.

MP


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Todd Terry
Re: Power distribution
on Aug 4, 2008 at 5:16:36 am

Hey Michael, thanks...

Yeah, unfortunately I know how it should be, but it rarely seems to be actually wired that way... we've been in some mighty funky buildings and its just impossible to determine what breakers actually go where, and what is isolated and whats not, etc etc etc.

Fortuantely all of our HMIs have Edison cables that are typically at least 50' 12guage (and I think one is even 10), but that's not the problem. The problem is solving the mystery of what loads are actually already on the circuits in unknown locations... and the people there are never of any help.

The vast majority of the bigger locations where we need the daylight gear are typically businesses... without typical kitchens where you know you have better luck isolating breakers or bathrooms where there are dedicated GFCI plugs for hairdryers, etc.

I know my load limits and capabilities pretty well... I just don't know theirs, and therein lies the problem

I guess I'm in need of some sort of magical load-testing instrument that doesn't exist... at least I've never heard of one that will show you the load that is already on a circuit.


T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com






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Thompson Coles
Re: Power distribution
on Aug 20, 2008 at 4:07:17 am

So I ask my father (master electrician) if the same device existed a couple of years ago. good news they do, a nifty device that you can plug into an outlet ant it will estimate that circuit's current draw. The bad news is that they start at around $1,500 and are really hard to find. I cannot even remember what they are called. I'm sure that if you searched the Klein tools website you might find one. Since it is out of my budget I never pursued it. Here's what I do, first of all I do the same thing that I'm sure you and others do every time i use local power with my lights. I ask if someone there has any clue to the power situation, breaker box, distribution, load limit. second i warn them that I am not just plugging in a light bulb, more like 150 light bulbs. this sometimes helps with people getting pissed if i trip a breaker.


after all of that here is what i look for when i.m searching for power.

I count the outlets. not individual plugs, but the boxes. most current office buildings will have no more than outlet locations per circuit and that is massivly pushing it.

i never use two outlets that are in sight of each other (exception is on a large show room and they have to be across the room in a bg way)

Look for a break room with a sink. the reason i say that is usually a kitchenette is given it's own circuit. unplug the microwave and pray the fridge doesn't have a ice maker.

I try to use a line from the garage, a line from the kitchen, a line from the bathroom, a line each from opposite sides of the house or building.
if there is an exterior plug that works at times.
I avoid anything that already has a power strip connected to it. also car dealers are famous for making cubicle office space with everyone on the same power.

good luck I hope this was somewhat helpful.

Thompson


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Todd Terry
Re: Power distribution
on Aug 20, 2008 at 5:09:05 am

Yeah, all the usual tricks are always in play, but still it is hard to estimate and no one ever seems to know anything about the buildings that we seem to find ourselves in ("Breaker box? What's that?").

Biggest challenge is when using 1200w HMIs (which I do frequently). They pretty much have to fly solo on their circuit. If you happen to be on a 15amp circuit, there can pretty much be absolutely nothing else on it.

The good news is apparently something does exist that does what I was talking about. $1500 is a bit steep... but I'd pay it for a device that does that if it really works.


T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com






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