Fuses for flashes, how much?

[Jozef Zajaz]

Hi!

I'm renovating the studio and was wondering how to find out how many fuses i need per outlet.

I'm currently using elinchrom digtal rx 2400ws.

[Jonathan Wienke]

(Watt-seconds of all flash units plugged in to circuit) / (full-power recycle time in seconds) / (AC voltage) * 2

So if you have a 2400 w/s unit that takes 2 seconds to recharge after a full-power flash and your line voltage is 240 V,

2400 / 2 / 240 = 5 amps drawn during recycling, * a safety factor of 2, = a 10 amp circuit breaker for that outlet. If you have more than one pack running at a time, adjust accordingly.

[bcooter]

Hi!

I'm renovating the studio and was wondering how to find out how many fuses i need per outlet.

I'm currently using elinchrom digtal rx 2400ws.

At minimum you want to have 20 amps a circuit.

If your remodeling talk to an electrical company about having at least another 100 amps run to your studio (200 is preferable) and then go through a distro box.

Standard 15 amp house breakers are cheap and prone to blowing under heavy use of if the ambient temperature is high.  They also wear out quickly with age.

This is just one option http://www.bhphotovideo.com/c/product/4246...ed_Through.html

and do a google search under distro boxes and you'll find a lot of options.  A professional distro box will last a long time and Mole stuff may be ugly but I've used some Mole Boxes on movie lots,  that I am sure were used for Gone With The Wind and they still work fine.

You can run 100 or 200 amps into a distro box, then three pin connectors out to edison or any type of connector so you can run hot lights when needed.

You can never have too much power, even if your running low wattage lamps, because hair and makeup can draw more power than a 5k.

Even in studio with proper amps I keep two honda 2000 generators on standby and it's saved me a few times when power goes down or you want to run some lights through a studio window and it's a lot easier to just run a generator than cross back and forth with 4 stingers all running around the set.

Also if you go to pro 7's you must have heavy duty extension cords (stingers) as pro 7's without the right extension will only let you go to half power with standard home depot stuff.

RGH in NY has them, their expensive but well worth it.

http://www.rghlighting.com/

Be careful of cutting corners on AC power.  A cheap box, a bad breaker, flimsy stingers and it's not only a time killer it's not too good for people either.

BC

P.S.  I guess I have to mention medium format for this post to be legal, so uh . . .  well if you shoot medium format you will need more amps for the same amount of depth of field you will get with a dslr.   So look into those 100 amp boxes.

[Jonathan Wienke]

(Watt-seconds of all flash units plugged in to circuit) / (full-power recycle time in seconds) / (AC voltage) * 2

So if you have a 2400 w/s unit that takes 2 seconds to recharge after a full-power flash and your line voltage is 240 V,

2400 / 2 / 240 = 5 amps drawn during recycling, * a safety factor of 2, = a 10 amp circuit breaker for that outlet. If you have more than one pack running at a time, adjust accordingly.

I forgot to include modeling lights. BCooters advice is sound, skimping on electrical is a recipe for frustration and trouble down the road.

[michaelnotar]

I forgot to include modeling lights. BCooters advice is sound, skimping on electrical is a recipe for frustration and trouble down the road.

Jon, what about if you change power on a pack? my speedo 2400 ws pack recycles to full in 2 secs but if i reduce power to 1200ws its roughly one sec, which is still the same watt secs per sec of recycle time in this case...

thanks

[Jozef Zajaz]

Great!

Thank you guys.

Live in europe so that box is nothing for me.

[UlfKrentz]

Great!

Thank you guys.

Live in europe so that box is nothing for me.

Hi,

of course we have Distri-boxes in Europe, too. For germany you may take a look at http://www.elektron-berlin.de/index2.htm
Running a 32A Box for example you can have 6 seperately fused plug-in-sockets for your packs. Altough they are extremely rough you should take serious care about the cables feeding those boxes. A missing wire (broken neutral conductor) can ruin a lot of your equipment.
For studio work I would always recommend to have dedicated seperatly fused plugin for each pack (running 240V fused at 16A, Type B or C). You should find a qualified electrician for that work. He could also advice you using the distri-boxes.

Cheers, Ulf

[UlfKrentz]

Jon, what about if you change power on a pack? my speedo 2400 ws pack recycles to full in 2 secs but if i reduce power to 1200ws its roughly one sec, which is still the same watt secs per sec of recycle time in this case...

thanks

...that´s why you will need the same fuse. There are packs that have a setting for slower recycling, these packs should have less current draw (but not all do in real world).

Cheers, Ulf

[Jonathan Wienke]

Jon, what about if you change power on a pack? my speedo 2400 ws pack recycles to full in 2 secs but if i reduce power to 1200ws its roughly one sec, which is still the same watt secs per sec of recycle time in this case...

So you still need the same minimum circuit breaker rating either way in this particular case. With the pack on a low power setting, it is harder to accurately time how long it takes to recharge, especially if it takes less than a second. If using a stopwatch, timing a full-power recycle will give you the most accurate picture of peak current draw. You always want to design for worst case maximum draw, so that your studio does not go dark if you accidentally leave the pack in fast recharge mode.

Factoring in modeling lights, the formula for minimum circuit breaker rating is:

( (Total pack watt-seconds) / (recycle time) + (total modeling light wattage) ) / (AC line voltage) * 2