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Fixing Multi-cable

Discussion in 'Lighting and Electrics' started by Dustincoc, May 4, 2008.

  1. Dustincoc

    Dustincoc Active Member

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    What is the best way to provide strain relief on multicables? I posted a thread a while back describing the issues we are having. The cable hasn't been terminated correctly and there is no chance of getting the money for the socapex connectors or anything else for that matter(They can barely pay to keep me for the summer to do the work). I'm just looking to patch them up for the next year, the theatre is being completely renovated starting next May.

    We're hoping that since they have an extra $400,000(supposedly) in the renovation budget that we'll be getting some new gear. We're hoping for 1-1 dimming in the new space and I'm going to recommend the replacement of multicable be on the top of the list.

    Unfortunately I'm being placed in the position of being told to fix everything lighting related this summer with a very small if existant budget for parts(Still trying to figure out how I'm sending dimmers in for repair with no money).

    I'm dealing with the sparking by cutting the cable back where the outer Jacket ends and striping back the outer Jacket about 2 foot, essentially duplicating what's already there but removing the bad sections on the ends.
     
  2. Les

    Les Well-Known Member

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    I believe there is something called Kellems Grips (or something to that effect) that is like a wire rope 'sock' or sleeve that provides strain relief for larger cables as well as multi-conductor.
     
  3. Dustincoc

    Dustincoc Active Member

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    I believe Kellums Grips are used for pulling and hanging cable to place the weight of the cable on the outside sheath instead of the interior wires where it could do damage.
     
    Last edited: May 4, 2008
  4. Les

    Les Well-Known Member

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    Correct. Sorry if I misunderstood your question.
     
  5. Dustincoc

    Dustincoc Active Member

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    I need something for where the wires come out of their sheath. What I have are 16 conductor multicable that breaks directly into Stagepin. The correct way to break a multicable into stagepin is to put a socapex connector on the multicable, then plug a socapex to stagepin breakout into it. Since I can't get(due to the budget) socapex connectors(which are rather expensive and difficult to install) which usually provide the strain relief, I need to find a way of strain reliefing the cable where the outer jacket end and the wires begin to break out into individual connectors.
     
  6. Sean

    Sean Active Member

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    Try looking at something like these:http://www.rshughes.com/products/051135_36001.html

    Of course, by the time you do all the heat shrinking, etc, you might have spent almost as much money/time as doing it the "other way".

    --Sean
     
  7. STEVETERRY

    STEVETERRY Well-Known Member

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    That construction is not compliant with NEC article 520, and would not be compliant even if you added sleeving and heat-shrink tubing. Your current setup is not really safe, since the inner conductor insulation is no longer protected by an outer jacket. Article 520 requires extra hard usage cord in a theatre (except as noted below), and what you have does not come close to meeting that requirement. My advice: for safety, fix it or take it out of service.

    You need to transition the multicable trunk to type S or SJ (or one of their variants) single-circuit, 3 conductor cables. If SJ (junior hard service cord), the cables must be under 20' in length. You can use a connector pair (like Socapex), or a listed electrical box with terminal strips, wire nuts, or butt splices to accomplish the transition.

    Proper strain relief must be provided for both the multi trunk and the single-circuit cables, the cheapest being listed two-screw connectors, and the best for the large-diameter multi trunk being a Kellems wire-basket grip. Kellems grips are not cheap, however.

    The box approach is terribly ungainly for humping the multi around, but it's cheap and code-complaint.

    ST
     
  8. Dustincoc

    Dustincoc Active Member

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    The multi-cable itself is type SO 16/C 12ga so I've got the cable part more than covered.

    I'll talk to the department director on Tuesday when he gets beck from NYC. The I talked with the teacher today and he told me that it shouldn't need strain relief and wrapping in in Electrical tape should be good enough. I understand the NEC thing and all and I wish we had the money but I'm basicly being told to make everything work safely(i.e. no students getting electrocuted) with what we have on hand. How much do breakout boxes cost, most of our multi is used for semi-permenant runs where we often hang lights but have limited circuits(such as FOH which only has one dropbox)

    If anyone could tell me where to get any documents on the NEC rules specifically regarding multicable, that might be a big help.

    My whole point in this post is to find a way to at least coming close to the spirit of NEC without having to spend a fortune that we don't have. I'm done with this theatre for now and my job is to clear off the unwritten to do list wihich is about 100 pages long. I'm trying to make it the safest I can for next years season as the place is being majorly renovated in a years time and we are really hoping to get some new gear at that point out of the excess from the renovations budget(as on now - $400,000). At that point, it we will have money, but for now I have to work with under $500 max for everything(unit parts, expendables, ect).
     
    Last edited: May 4, 2008
  9. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    I believe Sec. 520-68, "Conductors for Portables" is applicable.
     
  10. STEVETERRY

    STEVETERRY Well-Known Member

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    Sorry, but there is no "in the spirit of the NEC". The cable assembly either is or is not compliant. And electrical tape wrapped around the inner conductors surely is not. Your department director should be made aware of this, since there is liability for him or her.

    The parts to make the box at each end should cost no more than $50, but you need to get a couple of Greenlee punches to punch the holes for the two different size strain reliefs.

    Very important: you need to seek advice and supervision on how to make this box if you are not familiar with the tools, parts, grounding requirements, and risks.

    ST
     
  11. JD

    JD Well-Known Member

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    Funny the subject of Kellems grips came up. I just had one laying on my bench. This one would be good up to 1 inch dia cable. (they get a lot shorter) Kind of like a Chinese handcuff. The two eyelets go on the connectors regular strain relief screws. (See attached)
     
    Last edited: Aug 30, 2008
  12. Les

    Les Well-Known Member

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  13. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    No, but I'm not surprised. Consider what else one could put in a Kellems Grip.:oops: Strain-inducing, rather than strain-relief!
     
  14. Les

    Les Well-Known Member

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    Maybe if you find that the Kellems Grips from your electrical supply house are priced too high, you could find a similar yet cheaper version at your local adult toy store. Derek started it. haha
     
  15. avkid

    avkid Not a New User Fight Leukemia

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    Derek, that's just wrong.
    There are children about, so be careful.
     
  16. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    I was talking about this. Of what are you guys thinking?
     
  17. Les

    Les Well-Known Member

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    uh huh...

    :p
     
  18. Grog12

    Grog12 CBMod CB Mods Premium Member

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    1st rule of holes...when you're in one stop digging.
     
  19. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    Thanks, Grog. I've dug a hole lot a wholes, but nobody ever offered me that bit o' wisdom.;)
     
  20. soundlight

    soundlight Well-Known Member

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    Aww, but it's so much fun to throw them a big shovel after they've been digging with a trowel for a few minutes!
     

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