How to tell if worklight circuit is dimmed

[Les]

Hey guys,

So I'm working in a theatre where I'm adding moving lights for a show but there is no constant power readily available in lieu of running hundreds of feet of cable around to wall outlets. This was my original plan, but then I remembered that the space has worklight circuits spread throughout the electrics and grid (thrust-ish stage). These outlets previously powered par 64's for worklight but they have recently changed the system to something else, so they are now unused -- and are in perfect positions for my movers.

As far as I can tell, these circuits are not run through the dimmer rack. They are controlled by on/off push buttons at the stage manager's console. I assume they are connected through a contact closure, and to me this is the most likely scenario... Is there a way to find out by possibly metering the outlets? There used to be CAD drawings here but they seem to have disappeared.

I can say that there have been different consoles used in the space which never affected the worklights, and I don't think the rack can really configure things at this level (Colortran ENR), such as assigning certain dimmers to "non-dim".

I just want to make sure I have clean power for my VL2000's. If I can use these WL outlets, that will save me a ton of cabling and make the entire setup more safe in the long run - just need it safe for the fixtures also. I will be looking for any remaining CAD drawings tomorrow regardless. From what I remember, they were simply labeled "WL-1", "WL-2", etc.

 

[techieman33]

Not sure about using a meter. Is the labeling on the rack good enough that you can look at the drawer for that dimmer and see what it is? Maybe someone has an oscilloscope around and they could look at it with that?

 

[venuetech]

Perhaps you have a latching relay system. The one I have is a GE rr7 type that handles most of my work light loads. SSR tend to leak a bit of voltage when off. If your meter shows anything when the outlet is off, and no other load is connected, I would be wary. Make that a digital meter.

 

[BillConnerFASTC]

Do you know where the circuit breaker is?

I don't believe ENR ever had a relay module. Best I can say is try to figure out what each dimmer controls - a schedule - and chances if work lights don't show up in the ENR racks, they are not dimmed.

It shows you are in Dallas. System is ENR. High probability Texas Scenic sold and installed these. Ask them.

 

[microstar]

Actually, Colortran's ENR control modules contain switches that can set any dimmer to "non-dim" status. Obviously not a proper relay-operated or constant CC-20 type non-dim module, but at least the console is not able to accidently dim them or turn them off.

 

[chausman]

It's not necessarily reliable, but can you have someone in the room with the rack listen while someone turns the work lights on/off? See if anything clicks when the circuits come on. Our worklight relays are in a separate unlabeled panel, but it's obvious where they are if you're in there because of the noise.

 

[BillConnerFASTC]

Actually, Colortran's ENR control modules contain switches that can set any dimmer to "non-dim" status. Obviously not a proper relay-operated or constant CC-20 type non-dim module, but at least the console is not able to accidently dim them or turn them off.

Yes, like all SSR modules in some regards, but not an air gap relay suitable for powering LED's, movers, and similar solid state devices, or at least not in my opinion.

 

[venuetech]

It's not necessarily reliable, but can you have someone in the room with the rack listen while someone turns the work lights on/off? See if anything clicks when the circuits come on. Our worklight relays are in a separate unlabeled panel, but it's obvious where they are if you're in there because of the noise.

this would be the quickest way to find them.

 

[Robert]

So, I would turn off each breaker in the rack and see if the house lights still work.

 

[derekleffew]

... can you have someone in the room with the rack listen while someone turns the work lights on/off? See if anything clicks when the circuits come on. ...

That's actually pretty genius there, Chase.

@Les, in any case, it's prudent and wise to know where the OCPD(s) are that control ANY circuits you may be using. Once you find the circuit breaker s, you'll have your answer. I strongly suspect they're external to (but perhaps adjacent/near) the Colortran ENR dimmer rack. Being the Murphy's Lawist that I am, I'd worry about the switches inadvertently being turned off at an inopportune moment, so take the time for LOTS of labelling of all stations, up to and including makeshift protective covers, i.e. Molly-guard/(bottle caps?) over the switches in question.

So, I would turn off each breaker in the rack and see if the house lights still work.

We're talking about WORK light circuits, not HOUSE light circuits. One should expect House Light Circuit(s) to always be found connected to a dimmer, be it the main dimmer racks (if the rack(s) is fed to full nameplate capacity per NEC 520.27(C)(2) ), or an auxiliary rack (with separate feed) nearby.

 

[Robert]

That's actually pretty genius there, Chase.

@Les, in any case, it's prudent and wise to know where the OCPD(s) are that control ANY circuits you may be using. Once you find the circuit breaker s, you'll have your answer. I strongly suspect they're external to (but perhaps adjacent/near) the Colortran ENR dimmer rack.

We're talking about WORK light circuits, not HOUSE light circuits. One should expect House Light Circuit(s) to always be found connected to a dimmer, be it the main dimmer racks (if the rack(s) is fed to full nameplate capacity per NEC 520.27(C)(2) ), or an auxiliary rack (with separate feed) nearby.

Meant to say to say see if the work light circuts still work when the dimmers breakers are off. My bad. At least this would let him know if they are on the rack. I'm with you. I know where the breakers are for everything in my spaces.

 

[JD]

1) Unplug your work lights.
2) Turn the control switch off.
3) Measure for voltage at any of the work light outlets.

A) 0 volts - Not on a dimmer
B) Not 0 volts - It's on a dimmer

 

[Les]

Hey guys-

Thanks for all the help! I do still need to locate the breakers, but the outlets metered zero with the work lights switched off so I went ahead with the install. Ran everything for several hours tonight and all seem happy aside from some strange personalities in Magic Q (I'm just gonna roll with it). I am still making it a point to find the panel (because Murphy's Law) but that is tomorrow's task since today was spent slinging cable.

Luckily there is only one button station at the SM console - where the ASM will be stationed. Things labeled regardless and this is a pretty good cast so I'm not too worried. I'm just glad I don't have to expect my board operator to go around plugging in extension cords before house opens.

Let me tell you... Hanging VL2K's using a single-man Genie lift is no fun.

 

[BillConnerFASTC]

"One should expect House Light Circuit(s) to always be found connected to a dimmer, be it the main dimmer racks (if the rack(s) is fed to full nameplate capacity per NEC 520.27(C)(2) ), or an auxiliary rack (with separate feed) nearby."

Well, its a new era, and for several years the house lights in all of our new build projects have been LED, so not connected to a dimmer rack.

 

[JD]

but the outlets metered zero with the work lights switched off

The problem is that if the work lights are still plugged in when you make the read it would not be a valid test. The firing circuit inside a SSR allows leakage by its very nature. A load will make that leakage invisible unless the idle set is high enough. Once unplugged, it is common to read 70 to 120 volts with the dimmer set at zero depending on the meter.

 

[RideTheSquirrel]

Let me tell you... Hanging VL2K's using a single-man Genie lift is no fun.

Using a single-man genie is just not fun in general, ever. I hate how much sway those things can have when you're working at 25ft on a 30 (or maybe it's 35)ft max height rig. I'm usually good with heights but I don't trust that kind of sway any farther than I could pick up the whole machine and throw it.

 

[Les]

The problem is that if the work lights are still plugged in when you make the read it would not be a valid test. The firing circuit inside a SSR allows leakage by its very nature. A load will make that leakage invisible unless the idle set is high enough. Once unplugged, it is common to read 70 to 120 volts with the dimmer set at zero depending on the meter.

Sorry I wasn't very clear. The button was switched off. Work light fixtures haven't occupied the circuits in years, so there was nothing connected.

Using a single-man genie is just not fun in general, ever. I hate how much sway those things can have when you're working at 25ft on a 30 (or maybe it's 35)ft max height rig. I'm usually good with heights but I don't trust that kind of sway any farther than I could pick up the whole machine and throw it.

I could go on and on about their Genie. It's in horrible shape. The outrigger sensors have never worked right. Word has it, a former TD tried to trick the system by shoving 2x6's in the outrigger slots and it has never been the same since, and apparently Genie can't fix it. Of course this is the same venue where I've seen LD's seriously overtighten the outriggers. One time I walked in to find the lift with its grey wheels raised a full 8" off the floor and the thing was sitting at about a 5° angle while the (seasoned) LD was still trying to figure out why his green lights weren't on.

Just goes to show: Even though one has experience doesn't mean he is trained or knows what he is doing.

 

[JohnManderbach]

Sorry I wasn't very clear. The button was switched off. Work light fixtures haven't occupied the circuits in years, so there was nothing connected.



I could go on and on about their Genie. It's in horrible shape. The outrigger sensors have never worked right. Word has it, a former TD tried to trick the system by shoving 2x6's in the outrigger slots and it has never been the same since, and apparently Genie can't fix it. Of course this is the same venue where I've seen LD's seriously overtighten the outriggers. One time I walked in to find the lift with its grey wheels raised a full 8" off the floor and the thing was sitting at about a 5° angle while the (seasoned) LD was still trying to figure out why his green lights weren't on.

Just goes to show: Even though one has experience doesn't mean he is trained or knows what he is doing.

I hate to break in on your conversation but this Genie should be replaced if it can't be fixed. Is it very old? We use 2 Genie brand single man lifts almost every day. We have them serviced and certified every year. It's always the same technician and he has fixed or replaced the outrigger sensors plenty. It's just a metal tab with a microswitch.

And we often find ourselves at the top of the travel. I agree it is unnerving, but it is safe if you follow the directions.

 

[Les]

I agree about the Genie. As far as I know, the Genie was purchased when the building opened in 1995. It has been around at least since 1999, which was when I came around.

As for servicing and certification, I can't say I know much about their process. I only do about 1 show every five years in this space (used to be more frequent). I figured the sensors were simple.

For the most part I'm not worried by it, but the outrigger that insists on being a bit more loose definitely needs to be serviced, which I am putting a recommendation for.