What AWG wire to use on 50A 220V single phase?

bubba966 · « **on:** 30 Apr 2005, 02:16 am »

I'm going to be helping install a projector that draws 40A on 220V single phase. So I figure running a 50A 220V circuit should be OK. But I'm having trouble finding out what size wire needs to be run for 50A 220V. Anyone have an idea, or know someplace I can find out?

rmihai0 · « **Reply #1 on:** 30 Apr 2005, 02:37 am »

Anything between 6 to 9 should work.

bubba966 · « **Reply #2 on:** 30 Apr 2005, 03:11 am »

I did find 6AWG listed as good for 55A. But is that 55A @ 120V or 55A @ 240V?

Wouldn't 50A @ 240V = 100A @ 120V? If so, then 2AWG should be good as it's rated at about 100A if the ratings are for 120V. Or am I getting something mixed up here?

If only I'd been a sparktrician I might already know the answer...

markC · « **Reply #3 on:** 30 Apr 2005, 03:47 am »

Amperage is the concern here, not the voltage. 30A=10 ga, 40A =8ga, 50A=6ga, 60A=4ga. There are also limiting factors with length of run, but these are the rule of thumb.

shokunin · « **Reply #4 on:** 30 Apr 2005, 04:27 am »

I wired 4 gauge wire on a 60amp breaker to power one of my woodworking machines, well it's a rotary phase converter, but it powers a number of 3 phase motors in my shop.

bubba966 · « **Reply #5 on:** 30 Apr 2005, 05:10 am »

I think the run will be around 15'-20'. Maybe less.

That shouldn't be a problem, right?

shokunin · « **Reply #6 on:** 30 Apr 2005, 05:28 am »

15' 20' feet should be no problem 150' or 200' might be another issue. Is an electrician doing the wiring?

peranders · « **Reply #7 on:** 10 May 2005, 02:44 pm »

Quote from: bubba966

I'm going to be helping install a projector that draws 40A on 220V single phase. So I figure running a 50A 220V circuit should be OK. But I'm having trouble finding out what size wire needs to be run for 50A 220V. Anyone have an idea, or know someplace I can find out?

Just wondering, does the lamp really consume 11 kW? What kind of projector is that?

bubba966 · « **Reply #8 on:** 10 May 2005, 03:21 pm »

Depending on how you have the current set on the lamp house it can draw up to 65 amps! But it's being set down to it's lowest setting first (38-40 amps) to see how that works in the setup. I'm sure that'll be more than enough as this is a commercial film projector that's being used on a 12'6" wide screen. Which is a lot smaller than the 40' or so wide screen that it was intended for.

Anyway, the run ended up being about 40'. And wiring it up was easy. The lamp hasn't been ignited yet, but so far everything else has fired up fine.

peranders · « **Reply #9 on:** 18 May 2005, 01:48 pm »

Do you really have to choose a cable for 50 A continuously? How big is your fuse?

Maybe you should use a soft starter (check my homepage) if your only problem is a huge start up current.