Silly Power Question

[liteman]

Hi all,

I'm working on a show in an old venue. I have access to a 60A 240VAC event power plug (NEMA 18-60 Plug).

My desire is to bring in a few moving lights and wash units and supplement it with a small conventional package.

I was thinking I would build a custom distro for this. I was going to basically wire the first hot leg to Phase A on my dimmer pack and throw a 20A breaker on the end for half of my intelligents, and do the same with the second hot leg, for Phase C and the other half of my intelligents.

Right now, my current plot requires that my total intelligent light load is about 10A/120V on each breaker.
My total conventional light load is about 40A/120V on each phase.

My question is:

If I rent an ETC 12 x 2.4kw Sensor dimmer pack, which should really use 120A, will it still work given that my available power is less than that? Does it matter since I'm only loading each phase to 40A/120V, which is available, or will the pack not work at all without 120A?

Any responses, ideas, alternatives, or suggestions will be greatly appreciated.

Happy Holidays!

--liteman

[David Ashton]

The dimmer pack will only draw less than 100 watts, it is the load that you plug in and bring up that is the crucial factor.You can load up the dimmer but as long as you only bring up a balance of power at any time you can get away with it.The pack will work perfectly well.

[liteman]

Excellent. That's just what I wanted to hear.
Thanks!

One more silly power question:
I know that most moving lights these days can run at 120V or 220V. When they run at 220V, are they running off of a single leg at 220V, or two legs of 110V?

My real question is, using the above event power, can I hookup my moving lights directly to the 240V interface? If so, how do both legs of power get into the moving light? Do I need special power cables?

Also, what's the safest way for me to get the cam cables for the Sensor Pack hooked up into my custom distro without me having to wire cams out of my distro?

Thanks again for all of your help and your (incredibly speedy!) responses.

--liteman

[derekleffew]

liteman: STOP! If this is indeed the plug to which you are referring, it cannot safely be used for stage lighting, or anything else for that matter, as there's no electrical ground.

Secondly, you haven't told us what size the circuit breaker or fuses are supplying that receptacle, which is more important that the plug specifications.

Thirdly, your questions indicate that you don't have enough knowledge or experience to do what you're attempting without a Licensed Electrician.

Sorry to be blunt, but I don't want you or anyone else to be harmed. allthingstheatre is only partially correct regarding underrating dimmer loading, and didn't pick up on the fact that you refer to a NEMA 18-60 as a 60A 240VAC device, when it is actually a 4wire, 3ø, 120/208VAC connector, with no ground.

Welcome to the Control Booth! We'll do our best to help you with any question, but we'll also tell you when we can't, for safety reasons.

[wolf825]

Howdy liteman,
When it comes to electricity--the rule of "if you have to ask, you should not be doing it" applies.

Aside from not knowing how or what that 60a 'event plug' is wired (is it WYE power, is it delta power, what guage wire, how is the ground or neutral run, is it 'really' 60 amps or is that just cause the plug is rated for 60--it could be 100 or it could be 30--is it breakered or direct tie to a panel and what is THAT say, and is it single or 3 phase etc etc etc)--cause in electricity it is risky and dangerous to assume anything and there are many factors to consider for safety and proper use.


There is a liability restriction to questions that can be answered here on CB (most being for rigging and high voltage electrical wiring) for reasons of safety and liability because many of the participants on CB are learning students in HS and college. The Senior-Team Moderators & Controlbooth Owners, who are all experienced professionals, have drawn this line for its CB members so as not to permit posting of potentially dangerous or unsupervised 'DIY instructions' which may cause injury or harm to someone less experienced or just learning.... We do not wish to seem to play down the dangers and risks of doing certain rigging or electrical work. Reading a post on a web forum is not "formal training" or can cover completely all the safety aspects of any project... Supervision and proper training in certain aspects of live entertainment is required and a must before anyone should take on such a project. I am not saying you may not have some experience in electricity--I am simply saying that when in doubt always yeild to a professional electrician or rigger and consult them first.

Please consult a licensed electrician for your project and please be safe--we want our members to stay around. At the least, you could damage or destroy your equipment with improper wiring, and at the worse you could cause injury, death, electrocution and fire from mis-wiring or overloading...

-w

[liteman]

Thanks for your replies,

I apologize, I should have been more specific. I didn't assume that it was wired at 240V/60A because of the plug rating, it is clearly labeled on the disconnect that the plug is wired to.

In addition, each of the poles on the plug itself is labeled, as well. I've attached a picture of the plug that I took on the first site survey.

You're correct in picking up in my lack of knowledge about some of these things. I am really more of lighting designer, and usually let the production companies handle the setup, but this is for a small, non-profit organization, and I'm friends with the director, so it's a special circumstance. But I do have a fairly strong understanding of electricity and what is safe and what is not.

I would have never known that the Nema 18-60 is normally used as a 3-phase with no ground. i just assumed that it is normally used as it was wired in this situation, but clearly, the original electricians retrofitted it, into what seems like event power.

The top pole is labeled as neutral, left and right as the hot legs, and the bottom as ground.

Based on these labels, and the labels on the disconnect, I came to the conclusion that it was a single phase 240V/60A with two hot legs, a neutral, and a ground.

I certainly appreciate all of your concerns. I would never want anyone, including myself, to be harmed or put in danger by anything that had my hand in it, and I assure you that I will be the first person to step back if I even have an ounce a doubt in what I am doing.

I was a little weary about a few things that I had never had to deal with before, as I've always worked with an abundance of power and normally let others worry about power issues, which is why I came with my original question.

Again, thank you all for your responses, and your concerns - I appreciate them all.

-liteman

[jonhirsh]

In that photo it looks like top, left, and right are labeled H for hot and the bottom G for ground. That is a type of three phase power. Are you positive that the top said neutral?

[derekleffew]

Glad we didn't scare you away. I'll now address some of your questions, but I'd feel better if you had a more experienced electrician helping you.

The Sensor Pack, SP6, is normally set up for 3ø operation. It needs to be modified by its owner for single phase, GNHH, operation. I'm not positive, but I think dimmers 1-6 are on one leg and 7-12 are on the other, when used in single phase mode.

All of your intelligent lights are set to operate on 120V, correct?

You never told us the size of the fuses or breakers, or wire feeding the 60A receptacle. Measure the voltage on the receptacle to verify that the pencil labels are correct. Are you dealing with a venue maintenance person or some other building representative?

Another issue. If it is in fact a 60amp breaker protecting that outlet, you'll need to wire your plug with #6 or better #4 wire. Then find a set of E1016series-compatible Camlok-type connectors to mate with the Sensor pack. Those connectors wired with #4 or #6 wire are not a common item, in any company's rental stock. Plus the neutral MUST be oversized.

That's as much as I feel I can give you. Start a new thread in the New Member Board introducing yourself. We're lovable, but nosy. Tell us where you are and what you've done, and where you'd like to be and do. We like other's websites, and definitely post pictures of your benefit when it's done. We love pictures, there's a lengthy thread here.

[icewolf08]

If your Intellignet lights really only have a total load of 10A it would be a lot safter to just put them on a dimmer. I know that most intelligent gear doesn't like being on an SCR, so if you can spare two slots in your 12-pack you could put a CC-20 or R20 module in to feed the MLs constant power. In a pinch if you set the dimmer to switched mode you could probably get a way with running the MLs on a dimmer. This would be by far safer and easier than building a custom adapter.

[JD]

A plug like that would give me pause for thought. Three phase components cost a heck of a lot more that single phase parts. So, beyond the question of why a contractor would put the wrong receptacle in, is why would they pay so much extra money to put the wrong one in? (!)
The two answers that come to mind are:
1) It really is that type of power.
2) It wasn't a licensed contractor that installed it.
In any case, "Danger Danger Will Robinson!" Someone indicated to you that it is HHNG, but it needs to be checked out or better yet avoided!