Conventional Fixtures 6K Dimmers, 60A cables, and Five-fers

[rayhomme]

Hey,

After I posted this in another thread I noticed that it hadn't any action since 2004. So I'm starting a purpose built thread. thanks!

Hey,

I'm taking a bunch of cyc lighting on an upcoming tour. We have 15 4-Cell cyc units @ 1k each. Each color is channeled all together.

To keep it simple we're getting ETC sensor 6K dimmers and running 5 cells per dimmer. This means the whole thing is run from 12 6K Dimmers. The dimmer outlets are 60amp stage pin connectors. So for every 5 cells I have one 60amp cable going to the pipe.

I'm wondering what the best way to break the 60amp cable into 5 20amp stage connectors is.

I could get 60amp-20amp threefers then break two down further with twofers. There still would be a lot of cable involved in distributing this.

Because this is a single purpose set up that needs to install relatively quickly in a touring situation I'd like to create some custom cables for this.

What I imagine is a 60a male stage pin to 6/3 cable to 5 junctions out of which come a single 12/3 cable to 20a stage pin. The junctions would occur at the spacing of the cyc units making for quick installation.

Something like this:

=60amp---6/3---0---6/3---0---6/3---0---6/3---0---6/3---0
______________|_______|________|_______|_______|
____________12/3_____12/3_____12/3____12/3____12/3
______________|_______|________|_______|_______|
____________=20a____=20a____=20a____=20a___=20a

(actually the last junction is not necessary but I've just keep the illustration simple)

Has anyone make such a thing. Is there such a stock theatrical junction?

thanks in advance.

Will

 

[DuckJordan]

Is be worried about creating a custom cable not readily found. What about a soco breakout? Run it all through the soco and break it out along the pipe?

Sent from my ADR6300 using Tapatalk

 

[mstaylor]

I have never seen a touring 6K Sensor dimmer. I would assume it would or could be broken down at the rack. If it isn't already broken out in the rack to a soco then you could do it just downstream of the rack. You could come out with a cable that breaks into another distro to get to be all soco. The problem is once you get to the pipe you have to break it out and distribute it down the electric. To make it a faster set up why not go with standard dimmers and soco them.

 

[JD]

Can't go to 12/3 without current limiting. You are best sticking with 2.4k dimmers and Soco.

 

[derekleffew]

Re: 6K Dimmers with 60amp cable to 6 1k Cyc Cell

...To keep it simple we're getting ETC sensor 6K dimmers and running 5 cells per dimmer. This means the whole thing is run from 12 6K Dimmers. ...

This really isn't simplifying your life any. Here's why: you can't (code-compliantly) change (reduce) wire sizes and/or put a 20A receptacle on a circuit protected by a 50A breaker. You'd need one of these

PowerHOUSE™ Portable Distribution Boxes: 60 Amp Motion Picture Brick | Lex Products . (I understand it can be ordered with 20A stage pin receptacles.)
for each 6kW dimmer.

See also this thread http://www.controlbooth.com/forums/question-day/17412-what-247-60a-sixfer.html , paying particular attention to this post.

 

[SteveB]

Re: 6K Dimmers with 60amp cable to 6 1k Cyc Cell

Without using the boxes as per Dereks post, you are not code compliant. Which begs the question as to whether 6k's are any help to you when you have to be using breakout boxes. 2 solutions I see.

1) Swap the 6kw's for dual 20's and use regular 6 circuit multi's, or;

2) Use LED's. If you are tech'ing somewhere and building cues from scratch, I suspect the LD will LOVE the LED's, and I know you probably will down the road with a whole lot less cable needed.

Only problem with the LED's would be if it's a re-hash of a tour that's already been cued or you are not tech'ing, as trying to match the cyc looks from conventional to LED is a cue by cue trial and error process.

 

[mstaylor]

Re: 6K Dimmers with 60amp cable to 6 1k Cyc Cell

To get it compliant, there are a couple of options but it is far from easier. I suppose the idea is less road cases but it really isn't. Once you add distros or breakdown cables, it adds cases. Going to 2.4K dimmers and socos it will leave four spares on that electric in case of problems.

 

[rochem]

Re: 6K Dimmers with 60amp cable to 6 1k Cyc Cell

Saw this over on the SML and read it with interest, but now that it's here, I'll throw in my 2 cents.

While I see the logic behind carrying large-capacity dimmers for this purpose, I think you might be better off just sticking with a bunch of 20A modules. First of all, touring with lots of 2.4k dimmers and 6k dimmers means you'll need spares on hand of both types. When you run out your cable, you'll also want a minimum of one spare 60A running to the pipe with your looms, which adds significant weight and mass, and you'll certainly want a good selection of spare 60A cables in a trunk in case something happens. Keep in mind that 60A dimmers and cable is also going to be more expensive to get from the shop, because 2.4k dimmers are the "norm" and you're pulling something that probably sits on the shelf fairly often. Also, as you seem to have realized, cabling this quickly is going to be difficult. There's really no practical way (that I can think of, at least) to bundle everything in advance so that you can speed up your hang during load-in, unless you plan on touring the cyc lights in truss or something.

I would suggest that your best bet might be to just use 20A dimmers for these units. A couple questions: Can you convince your LD to switch to 750w lamps instead of 1k? Can you maybe switch to a different type of fixture, like mini strips, or even Colorblaze fixtures if you have the budget? Using 20A dimmers, you could cable all your cyc units with 6 mult runs/32 dimmers and have four spare circuits. If the LD is willing to bump them down to 750w, then you can do it quite easily with 4 mult runs/20 dimmers and still have 4 spares. This might actually turn out to be much easier than trying to break out of 60A cable, because you can bundle all of your breakouts and twofers and jumpers together so that all you need to do at load-in is slap one big cable loom onto the pipe and plug in the mults.

Actually, hold on. Someone correct me if I'm wrong, but you can put 50A and 100A dimmer modules into a standard Sensor touring rack alongside D20 modules, right? The best of both worlds might be to run your multicable and breakouts as if you were using 20A dimmers, then just patch them into the high-capacity dimmers at the rack. This would give you the advantage of being able to use normal twofers and jumpers and soca, while still keeping everything in a smaller number of high-capacity dimmers. You'd just have to be very aware of your patch and label things very well so that you don't accidentally overload any of the dimmers, but that shouldn't be a problem as long as you make everything clear and pretty in the shop.

 

[danTt]

rochem: While your last solution is certainly a cool trick, I don't think it really gains anything (except for the breaking code part). If you are only combining it at the rack, you might as well use d20's and just take the extra five seconds to patch another part--Or what if the designer decides during tech that he absolutely must split the cyc into a few different sections? If you do all the combining in the rack, not only are you relying on memory/personal labels to prevent mistakes, your also probably introducing pinpatch twofers, which I seem to recall have their own collection of issues, although they certainly are useful.

EDIT: actually more to the point, what about if you run into a short in one of these fixtures using the 50amp dim/20a cable? The breaker won't trip until you are pulling a lot more current than the cable is rated for--correct?

 

[derekleffew]

Re: 6K Dimmers with 60amp cable to 6 1k Cyc Cell

...Actually, hold on. Someone correct me if I'm wrong, but you can put 50A and 100A dimmer modules into a standard Sensor touring rack alongside D20 modules, right? ...

Correcting you (if) you are wrong...

Here is a side note on the use of 50A modules (D50AF). While a D50AF will fit in any open slot in a Sensor rack, the backplane of the rack has to be wired correctly for the output. A D50AF module is NOT a dual module, it has only one dimmer instead of two like the D20. Thus you can't just pop one in when you need it, you have to have the proper wiring out of your rack and in your walls or raceways.

It is possible to convert a slot in your rack to or from a 50A slot, but this should only be done by an ETC certified technician and the output wiring would need to be done by a licensed electrician.

 

[danTt]

derek: That quote sounds like it's just saying that if you drop a d50 where two d20's were, one of those two circuits will no longer work (along with the associated implication that the wiring needs to be upgraded if you have a d50 dropped in). On a touring rack I'd imagine this would be less of a problem from a technical end, as the output panel is right there--you'd still only have 20amp rated connectors at that point though, which is where the problem lies.

Of course, I could be, and usually am, incorrect, and I'm not in any way supporting the d50 in this case, but I think that's what this is all saying.

And, on a related off topic note, how is something like this feasible/legal?
http://www.bhphotovideo.com/c/product/355804-REG/Mole_Richardson_72978_Adapter_SOCAPEX_to.html It looks like they are using multiple wires on each terminal to distribute the load? Is it supposed to work that way?

 

[derekleffew]

...And, on a related off topic note, how is something like this feasible/legal?
Mole-Richardson Adapter - SOCAPEX to 60Amp Bates, 2 72978 B&H It looks like they are using multiple wires on each terminal to distribute the load? Is it supposed to work that way?

The picture

doesn't match the description:

This cable adapter permits connection of a Mole Richardson 2K or higher Spacelite fixture to 2 separate cables, or dimmer panel sockets via its 2- 60 Amp 3- pin Bates plugs.

This picture is what they meant (or the reverse--one Male Soco to two Female 60A 2P&G's):

but that doesn't make it any better. I've only seen this in the field once, by a lighting company that should remain nameless.

...1. Paralleling of two 20A circuits in the Socapex cable to a 50A overcurrent device is not permitted. Paralleling of conductors is only allowed on conductors of 1/0 AWG or larger. [310.10(H)(1) Conductors in Parallel]
...
3. Adapters (and unfortunately that is what this mess is) are not allowed a reduction in ampacity (50A to 20A). [2011 NEC 520.69 (A). No reduction in Current Rating.]
4. If improperly plugged, this rig could be a fire hazard.
5. Only a moron would devise such a diabolical device.

And film lighting guys wonder why they have such a bad reputation? Since the majority of their work is of a short duration, they "get away with it" before an inspector catches them.

-----
rayhomme, sorry we've strayed so far from your original question. Here's how I'd do it:
View attachment TouringCycLights.pdf
I think I'd rather have 6x Soco multi-cables than 12x 6/3 cables going to the cyc light pipe. Plus using Socapex two-fers and standard 11' even break-outs is simpler than 28x stage pin two-fers and a multitude of 60A-20A adapters of some sort. Either way, you're going to need a crapton of friction/bundling tape and a very clear labeling system! Sixty-plus plugs on one pipe is 60+ chances for error.

EDIT: Don't forget to take into consideration diversity, electrical when loading up a multi-cable with 2kW on every circuit!

 

[SteveB]

The dimmer slots in a Sensor modules (EDIT meant to say rack) can accept any of the 3 sizes of dimmers, dual 20 or single 50 in one space or a single 100 using 2 spaces. In each case the branch circuit terminal lug is different and needs to be changed. As well, ETC either keeps tabs in place to prevent a 50 or 100a to be used in a dual 20 slot (due to different terminal lugs) or removes the tabs. As well, the wiring from the terminal is going to be different, thus you cannot remove a dual 20 and pop in a 50 as the wiring is 20 a rated. I would guess that once the shop configures (or purchases) a rack with 50 or 100 amp dimmers, they leave it set up that way and if you needed a 24 x 20a they would give you a different pack.

 

[rochem]

I'm not gonna quote everyone, but thanks for correcting me on the 50A dimmer issue. I had assumed without thinking about it too much that the slot numbers would remain the same, even if the dimmers in those slots didn't - if you replace the D20 module in dimmers 29 and 30 with a D50, then anything pin-patched into 29 OR 30 would still go to that dimmer, even though it's just one dimmer now. I didn't even think about the internal rack wiring. Good to know.

That said, Derek's solution seems to be the best option - although with a little more time, you might wish to distribute your spare circuits throughout your mults - personal preference I suppose. Oh, and if you don't want your local crew to hate you, PLEASE bundle those mult homeruns into two groups of 3, not all together as a 6x bundle.

 

[derekleffew]

Although many have provided excellent advice and answers, sadly, it seems to have been all for naught. The OP hasn't been back since posting the initial question. I continually wonder about the state of common courtesy and future of human decency when so often the axiom "no good deed goes unpunished" appears applicable.

File this also under "Why ask the question when you don't want to know the answer?"

-----
One solution proposed on the SML that hasn't arisen here:
Use 20A fused 2P&G female connectors. Though rare, these are available from Bates and possibly other manufacturers. These always seemed to me to be putting the OCPD in the wrong place in the chain, but I suppose it would work, that "weakest link" thing and all.

 

[STEVETERRY]

One solution proposed on the SML that hasn't arisen here:
Use 20A fused 2P&G female connectors. Though rare, these are available from Bates and possibly other manufacturers. These always seemed to me to be putting the OCPD in the wrong place in the chain, but I suppose it would work, that "weakest link" thing and all.

Err...I don't think so. A 20A female cable connector, fused or not, is only rated to #12 AWG cable. The length of #12AWG between the 60A connector and the input to the fuse in the 20A connector will not have coordinated overcurrent protection. This would be fine using a tap rule, but there is no allowable tap rule that applies to this hypothetical application.

I suggest 2.4kW dimmers.

ST

 

[BobHealey]

Is there a good, safe way to go from a 6KW dimmer to connectors rated for 2.4KW? I've found a theater with a 6 channel Sensor Portable unit with a breakout to 3 20A stage pins on each of its outputs. This is obviously bad and wrong, because 20A < 60A, and I would like to fix it.

I'm looking at 3 different options. Besides the 3rd option, which is inherently safe, are either of the other options viable?

Option 1: Replace the male 60A stage pin connectors with fused versions and install a 20A fuse in the connector. I "lose" 2/3 of the dimmer capacity, but all the wiring is protected.

Option 2: Replace the female 20A stage pin connectors with fused versions. The 6" jumpers between the male connector and the fuse would be undersized, so this is probably not legal or a valid option

Option 3: Lock out/tag out the rack, disconnect the camloc inputs, disassemble the three-fers, and hire an electrician to remove the breaker feeding it. See if there is a used market for 6 channel 6KW Sensor MPE units.

 

[derekleffew]

As seen above in post#5, the only code-compliant way to do this is to use http://www.lexproducts.com/products...0-amp-hollywood-box-to-3-nema-20-amp-circuits with 2P&G outputs, or similar. Cost would probably be about the same as hiring an electrician, but less than replacing with 20A dimmers.

 

[BobHealey]

As seen above in post#5, the only code-compliant way to do this is to use http://www.lexproducts.com/products...0-amp-hollywood-box-to-3-nema-20-amp-circuits with 2P&G outputs, or similar. Cost would probably be about the same as hiring an electrician, but less than replacing with 20A dimmers.

Using a 60A fused connector with a 20A fuse isn't ok? I'm just curious why. It sounds like lockout/tagout/remove is the direction I will go.

 

[danTt]

Using a 60A fused connector with a 20A fuse isn't ok? I'm just curious why. It sounds like lockout/tagout/remove is the direction I will go.

I believe it is. I've got some old 6k plugs that are fed by d20's now, post renovation. Your solution doesn't sound much different.