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Author Topic: Power snake for small truss.  (Read 2729 times)

drewgandy

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Power snake for small truss.
« on: May 04, 2004, 08:24:53 pm »

I'm looking for a 4 channel "snake" to run from a small multiplex dimpac attached to one truss over to a bar of lights on another truss.  Par 38s probably.  I haven't seen something like this and I haven't figured out what kind of wire to use to make one. Does some thing like this exist?  

Thanks

Warren
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Brian Ship

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Re: Power snake for small truss.
« Reply #1 on: May 04, 2004, 09:53:17 pm »

I use a digital quality audio snake for this purpose in lengths up to 400'.  Such a system has been done where I work since DMX came out, and there has never been any real problems with it be it snake boxes at the end of the cable with XLR/DMX outputs such as on store bought audio snakes, or in our current case, 37pin Socopex plugs on them leading to truss snake output boxes or multiple truss snake impute/output rack panels with patch tails off it's rear for patching.  At the moment, I'm a big fan of 16 pair 22ga snake cable.  In a truss/front of house snake with those plugs, it gives me six pair true five pin and two clear com.  After that there is two extra circuits for later use after things start breaking.  24ga is the normal multi-pair snake size and it works ok for a few years, 22ga is just a wee bit stronger.  For normal truss snakes a 8-pair cable should be fine otherwise.

There is more specific details about this on the old forum a search would pull up if it's any use.  It's also very much a question of the grade of multi-pair cable used in how dependable it will be.
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Rob Timmerman

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Re: Power snake for small truss.
« Reply #2 on: May 04, 2004, 11:25:12 pm »

If you're after a data snake, Brian's got some good advice.  But I'm guessing you're looking for something over which to run power.  For 4 lines, I'd either bundle 4 cables with friction tape, or spend the money and invest in a run of 12/19 with Socapex connectors and the appropriate break-in and break-out, which will give you 6 runs, not 4.  I don't know of anything else that will give you multiple circuits in flexible cable that meets the NEC.

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drewgandy

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Re: Power snake for small truss.
« Reply #3 on: May 06, 2004, 02:37:41 pm »

Yeah you got what I'm getting at.  I just thought a simple quad box on one end and a fan-out of 4 edison plugs on the other would have some use somewhere and that somebody made one.  For what I want to do now I'm not going to invest in soca yet.  I'm just looking for an easier way to do this.  btw, what exactly is friction tape?  

Warren
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Rob Timmerman

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Re: Power snake for small truss.
« Reply #4 on: May 06, 2004, 03:17:32 pm »

Friction tape is a rubber impregnated cloth tape that sticks to itself.  It's also used in things like hockey sticks.  Try searching, it's been mentioned before.
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Brian Ship

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Re: Power snake for small truss.
« Reply #5 on: May 06, 2004, 11:29:25 pm »

My bust, I thought you were meaning a data snake to the truss.  If it's just four circuits, it is probably most cheap just to tape/loom together individual cables into a snake.  Five to ten layers of electrical tape, five layers of gaffers tape per about three to four feet of run should be fine.  Hook one end up to a fixed position and have someone pull from a few feet away from where you are taping to get all cables the same length within the loom.  Don't pull with vehicles unless you also want that vehicle to break conductors inside the loom.

Simple and done.  Next best is to go with a Socopex cable assembly and what's called a fan out or breakout box as an alternative.  Both will have a male plug at the truss end or a female Socopex plug at the dimmer end than either have individual cords to power up the circuits, or outlets to power them up.  This is necessary because you really are not allowed to just strip wire and have exposed conductors going into individual plugs or circuits without a vulconized breakout from the cable and sufficient protection over individual circuits as per the overall jacket of the cable assembly.  Fairly obvious safety reasons.

This applies to the male plug end of this Soco like cable also.  Termination of either end in any thing other than a multiple pin plug is at best marginal in compliance with NEC standards for electrical boxes mounted on cords.  In other words, and at least in my opinion you cannot install 1900 wall boxes on the ends of the multi-conductor cables than even attach the ends to individual cords.  Not designed for this purpose and given 24 conductors as per my memory of box fill capicity even 12 conductors going to outlets or feeding thru is still too much.  A Soco cable would be against code to be spliced in such a box even if it's able to.  People do do this however, this is my interpitation.  The better way is to terminate multiple conductor cable in a multiple pin plug than attaching that to a box with capacity and space do a proper job of it and is removable so you don't have some heavy unwieldy box at the end of your cable when running it to the truss.  Such a thing would break down conductors.

Granted you were only planning four circuits and could make do with even a 16/10 conductor cable of SO grade if you bridged some grounds as would be necessary in any metallic enclosure.  It's usually cheaper overall to just go with a 14/14 conductor cable such as Coast, Duraflex, Oleflex or Proplex with Soco type 19 pin plugs on it and have the grounds tied into one.  Fan out from there.  Gives you room for growth or spares, and it being a standard size is frequently cheaper and pre-built in stock lengths.  Same with fan-outs or fan-ins into and out of the multi-cable or various truss mounted boxes you can pre-rig to the truss than just screw the cable into.

Hope it helps, sorry I thought you were talking about data lines to the truss.
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