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Safety cabling on a vertical bar?

Discussion in 'Lighting and Electrics' started by Clifford, May 31, 2008.

  1. Clifford

    Clifford Active Member

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    Yes, it's another thread about safety cabling!

    We have a vertical bar with four channels in both of our crowsnests. There doesn't seem to me to be any way to safety cable the lights on the bars. Is this normal, or are we missing something?
     
  2. Trolley01

    Trolley01 Member

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    We use these:

    Atom Hanging Clamp

    and then loop the safety bond through them. It is quite an expensive way to do it. Depending on how you are rigging your bar, you may be able to get two or three lights to the same eye.

    We have found that we needed to get some longer safety bonds to reach from the fixture to the eye on the bar.

    Just now thinking though, wouldn't the eye need a safety of its own!! :-s


    Alternatively, i've seen it where the boom arm has the loop of the safety through the bolt (in between the two sides of the arm). Did doubt this method a bit as it does make the boom easier to move and twist round.

    Probably is a better way to do it though.
     
  3. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    Yes, that's quite an expensive and possibly excessive way to do it.

    [user]Clifford[/user], we've discussed this before. There's no perfect solution. One method is to safety as normal. This will hopefully keep the fixture falling vertically, so it is stopped by the next light down, or by whatever bracket is holding your vertical pipe. Another way is to tie a clove-hitch around the pipe with the safety, then clip through the yoke. Another is to add an empty C-Clamp above the fixture and run the safety through that as well.

    As an aside, you ARE using side-arms, or cross-pipes with Fixed Cheeseboroughs:
    [​IMG]

    or Rota-Locks:
    [​IMG]

    or Grid-Locks:
    [​IMG]
    right? It takes much longer to focus a boom if the fixture is clamped directly to it, sideways.
     
  4. Clifford

    Clifford Active Member

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    These vertical pipes go into the cieling above and the floor of the crowsnest below. It's just one smooth pipe from top to bottom. As a sailor, I'm ashamed to say that I hadn't thought of the clovehitch. Previously, we've just been using the lights without safety. :oops: However, we do have fixed cheeseboroughs, that we use when creating multi-story sets with pipes. We've got tons of those. I think I like that idea best, and it sounds like one of the safest. Thanks Derek.
     
  5. Sean

    Sean Active Member

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    Derek,

    I have to disagree with you here. No clove hitches on my safeties, thankyouverymuch. The cables have clips for a reason. And, for those that doubt the safeties.....They're expendible. If something falls and is actually caught by the safety, then that safety cable is trash. They cost about as much as a cut of gel ends up costing.

    If you only have one light, and it's seriously up high, then the empty clamp method would be ok. Otherwise, especially with double-hung sidearms it's easiest to safety lights to their neighbors. The light closer to the boom pipe gets safetied around the pipe, and the "outside" unit gets safetied to the first unit.

    The safeties on shins, etc, drive me crazy. If it isn't a hazard to someone, you don't need the safety cable. This is one reason in support of NOT having the safety attached to the unit/yoke.


    --Sean
     
  6. MNicolai

    MNicolai Well-Known Member Fight Leukemia

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    The easiest route in my mind is extra C-clamps. If anybody else is like me, they have a few sitting around at a time that they can spare. If you don't, they aren't expensive.

    I have plenty of faith in empty C-clamps, but my advice is that if that's a route you're considering, don't take them down when you don't need them, just leave them up. If you put them up, crank them on, then you don't have to worry about them so much as if you're constantly changing them; then there's room for error if somebody were to not crank one down enough putting it back.

    Where does the serious concern lie though? My experience with vertical booms is that if the instrument isn't clamped on completely, the weight will shift in such a manner that the fixture doesn't free fall, rather it stays in place until you lift it, making it perpendicular with the pipe. Aside from that, if you just put the safety cable around the pipe the light will still fall, but will only fall to the next light or bottom of the boom. Even without that though, gravity will still prevail, and I'd guess that most people don't have audience members seated directly below vertical booms in the first place.

    If the boom isn't fixed, but temporary, my concern would be most placed in that if a light fell it would throw the boom out of balance when the shock load kicks in and next thing you know you're boom is toppling over.

    Another factor is how the boom is constructed. If it's a straight pipe floor to ceiling that's fine, but if it's vertical pipe mounted at the bottom with a stand off from the wall and doesn't connect to the floor, it certainly can't hurt to put a cable on fixtures there because they will be caught by the bottom pipe that's perpendicular to the vertical pipe and the wall.
     
  7. Clifford

    Clifford Active Member

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    Sorry to bring this thread back to life.

    There seemed to be some uncertainty as to the type of bar I was talking about. Just to clear everything up, I've attached four pictures.

    1) Taken from the SL crowsnest. The bar in question is to the right of the channel boxes. The shelf at the bottom of the 'window' is not as wide as you would think from this picture.

    2) Looking up at the top of the bar, it just goes into the ceiling.

    3) Bottom of pipe, stops at floor.

    4) Looking from the stage up at the SL crowsnest. Under that is the aisle and an emergency exit.
     

    Attached Files:

  8. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    Raceway. Yup, looks like a great place for three 2'-6" pipes, cheeseboroughed to the vertical pipe, and each holding two lights: top 2x 19°, mid 2x 26°, bot 2x 36°. Maybe even squeeze in a 4th crosspipe for specials or a template wash.

    I'm curious about the circuit labeling. Is 13A the same dimmer as 13B? What brand/model are your dimmers and board?
     
  9. Jezza

    Jezza Active Member

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    By the twist-lock outs it looks like his system might be dimmer-doubled -- YAY ETC (not).
     
  10. Clifford

    Clifford Active Member

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    We usually just attach the lights directly to that bar.

    Not all of our channels are labeled like that (in fact, I think it's just the crowsnest ones), but when they are, it means that they're on the same dimmer. The wash lights on the catwalk (which you can see part of in the top of the fourth picture) are 24 lights on channels 1-12.

    As to our dimmers, I can't tell you. This being a high school, we have angry bureaucrats at the district who don't trust us with them. There's an electrical room that we rarely get to see inside of where the dimmers are. I can tell you though, that our board is an ETC Express 48/96.
     
  11. patrickh

    patrickh Member

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    Re: Safety Cabling Top Hats/Barndoors

    Safety Cable anything that can be. I would rather have to undo a few extra safeties than have a piece of equipment fall. It is my job to keep my actors safe and that means they aren't going to get hit in the head. Now the real question, what is the best safety technique for securing S4's to a Boom?
     
  12. techieman33

    techieman33 Well-Known Member

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    Re: Safety Cabling Top Hats/Barndoors

    I don't know that I have ever seen anyone safety a fixture to a boom. I supposed if you really wanted to you could attach some rated chain to the boom tie off and run it down the pipe then attach the safety cables to it.
     
  13. josh88

    josh88 Remarkably Tired. Premium Member Fight Leukemia

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    Re: Safety Cabling Top Hats/Barndoors

    I've always wrapped safeties around the boom before connecting it to the light. That way if it were to fail and fall it creates a choke, tightening the loop around the pipe and keeping it from sliding down.


    Via tapatalk
     
  14. SteveB

    SteveB Well-Known Member

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    Re: Safety Cabling Top Hats/Barndoors

    We put a c-clamp above the top unit, then loop safeties off that as attachments. We don't safety anything under about 6ft.
     
  15. gafftapegreenia

    gafftapegreenia CBMod CB Mods

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    Re: Safety Cabling Top Hats/Barndoors

    I always use safeties on a boom. If a clamp should fail, I'd rather the light be caught by a unit below it than free fall to the deck.
     

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