Dimmer Beach & Racks Cable Management

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Hey friends,

Wanted to hear some opinions and thoughts on managing and dealing with all of your multi cable slack once its at the dimmer rack. I've seen lots of interesting and creative ways of dealing with it all, and was curious if there were some good pros or cons to any and all of them. Of course, I know if you have a lot of slack and you need to coil it you should always try to figure eight to avoid heat build up. But what about simply running the excess out and back in a "dog bone" fashion? I've been admiring the pics of Dimmer Beach Monthly recently, and how neat and tidy the cabling looks (or at least not like a giant rat's nest)
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I've also seen pipe structures built around the dimmer racks to allow for tying up the slack above the rack. Thoughts on this as well?

Again, just looking for any and all opinions or advice on dealing with all of your multi cable at the dimmer rack end, and tips to avoid a rat's nest.
 
I've been admiring the pics of Dimmer Beach Monthly recently, and how neat and tidy the cabling looks (or at least not like a giant rat's nest)

I've also seen pipe structures built around the dimmer racks to allow for tying up the slack above the rack. Thoughts on this as well?

Again, just looking for any and all opinions or advice on dealing with all of your multi cable at the dimmer rack end, and tips to avoid a rat's nest.

Most gigs on DBM seem to be super large one off events. That means they don't have to repeat the results and have some time to get it installed. Compare that with a touring set up and its a bit different. I do more touring than anything else so that is what I will speak to. PRG and most other lighting companies have giant set carts that allow you to load all your racks into. I like them alot. You leave the lids at the shop and don't have to connect any rack jumps on site. Some people don't like having to reach into something to make connections but I don't have much of a problem with it. Slack should be taken up with a cable pick whenever possible. If something is on the ground someone has to pick it up. If it is in the air the motor will put it in the case for you.

No matter what type of gig planing can make a world of difference. Your first cable down should be your last one up. Leave the ends pluged into the rack until you are ready for that cable to come up. otherwise they start to get tangled. The best way to learn how to be good at dimmers is to do a tour with a bad one and learn what not to do. Then do a tour with someone who is great and see how much easier it is.
 
I think that your slack depends on space, etc. One tour that came into a venue I was at would lay down a piece of plywood, coil the excess (can't remember the pattern), and then 3 - 4 people hoisted it up on top of the dimmer racks. I don't recall them having more than 10 lines, and none of them had more than 10 or 15' of excess so there wasn't a lot of weight. One tour I was on the ME had the bright idea of laying cable out UNDER the deck. All the locals had to get under and snake it between the legs and cross supports. It took 6 shows to talk him out of that.
I don't mind where the excess goes, or picking it up off the floor, just as long as it's neatly laid out and doesn't present a hazard.
 
I think that your slack depends on space, etc. One tour that came into a venue I was at would lay down a piece of plywood, coil the excess (can't remember the pattern), and then 3 - 4 people hoisted it up on top of the dimmer racks. I don't recall them having more than 10 lines, and none of them had more than 10 or 15' of excess so there wasn't a lot of weight. One tour I was on the ME had the bright idea of laying cable out UNDER the deck. All the locals had to get under and snake it between the legs and cross supports. It took 6 shows to talk him out of that.
I don't mind where the excess goes, or picking it up off the floor, just as long as it's neatly laid out and doesn't present a hazard.
One of the best solutions I've seen: threaded pipe flanges welded to the top of the dimmer racks (one on top of each corner). Screw in pipe and add a couple cross pieces. Worked great for that production.
 
That's actually incorrect, For heat dissipation you are needing to figure eight. He's not worried about inductance...

Hmm, interesting. So I understand now that inductance is only a worry if you're creating a coil with a single current carrying conductor. Meaning that, for example, when a neutral is running with it's hot, it's automatically counter acting the magnetic field that the hot is creating, since the electrons are theoretically running in the opposite direction of the hot. Right?

But still, I do agree that heat buildup can be an issue. In fact I've witnessed first hand with some multicables that were coiled up (it was probably 30'-40' coiled up) would get pretty hot to the touch. They were carrying a fair amount of power on them of course. So in the event that you do happen to end up with a multicable constantly supplying a lot of power, do you think it would help avoid heat build up if you were to run out the cable back and forth in a dog bone manner? Maybe like 10' segments or so? My instincts tell me it would, since there would be less cable segments piled on top of each other, reducing the heat transferred between segments.
 
That would help... honestly the best thing for cables is to suspend them in the air. The heat instead of being built up between the insulator and the solid surface is now being removed by the air currents.
 
That's actually incorrect, For heat dissipation you are needing to figure eight. He's not worried about inductance...
A coiled single conductor power cable causes heating due to induction. Heating and induction are not unrelated. You could coil a socapex cable in a larger diameter circle and create the same cooling effect as figure-eighting it. Figure-eighting a multi-conductor cable doesn't do anything magical for reducing heating other than increasing the airflow compared to a tight coil.
 
Pile = problem.
Laid out 1 layer = good.
The addition of fans as in the picture is real good. In that case, I am sure the fans are to keep the equipment cool, but moving air also helps dense cable areas.
The biggest problem with cable is when air is not moving. For example, look at the ratings for wire gauge when used in as an overhead service loop as compared to the same gauge threaded in a conduit. Look at how cables are de-rated as you add more conductors. It's all about heat. And heat is all about method of dissipation.
 
I'm noticing, at least on the B-Dway musical bus & trucks, that a lot more LED's are used, so the sheer amount of multi, as well as racks in general, are less. Until you get a tour that's been out years and using the same gear for 20 years, then it's 12 circuit.


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A coiled single conductor power cable causes heating due to induction. Heating and induction are not unrelated.

At 60 Hz, and with loops (turns) with a radius of several feet, wire inductance is so small as to not be a factor in heating. Plain, old resistance of the conductor is what causes heating of the cable. Watt's Law: P = I x I x R, where R is the resistance of the conductors and P is the heat dissipated by the cable.
 
I'm noticing, at least on the B-Dway musical bus & trucks, that a lot more LED's are used, so the sheer amount of multi, as well as racks in general, are less. Until you get a tour that's been out years and using the same gear for 20 years, then it's 12 circuit.


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I'll see that change in about 5 years. Too far off the main circuit to tell whats happening currently in Broadway Tech.
 
I like to keep coils neatly along my racks; round coils overundered. With large looms I like to leave extra length in the case, this way the cable can coil right back in as the truss/battens come in. Individual coils get moved to right under the truss, and can also coil on the way in.

When organizing coils sometimes you need to stack them. Establish a method of keeping them in order eg: US to DS. I like to plan for the first position that comes in to have its cables on top of the stack. Also for organization, I like to keep motor cables to the US edge of the truss and Power to the DS edge, I'm also careful not to cross or twist them in cable picks too. Same goes for plugging in all your soco's to the racks; avoid running them over/under/through motor and other cables that will need to remain a little longer.

Before everyone gets up in arms about heat, its really not an issue in most cases. I usually try for a minimum of extra cable, and not to heavily load circuits. Usually I do fixture per circuit and use 20A soca.
 
At 60 Hz, and with loops (turns) with a radius of several feet, wire inductance is so small as to not be a factor

Until the day you coil them under a corner of the stage, only to have the band set up their on-stage monitor mix directly above them! ;)

As for heat, I would agree, inductance is not a factor. Resistance and lack of air flow are.
 
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