# Light fixture safety cables



## Dagger (Dec 16, 2019)

I have seen safety cables being used to suspend for example da lite fast fold screens or chandeliers up to 200lbs.

Acceptable to use safeties to actually hold the weight?


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## Nic (Dec 16, 2019)

In short: no. No no no no. 
I have never seen a safety cable rated for overhead lifting. Many do have a published safe working load (WLL) but they virtually all come with disclaimers stating they are only to be used for their intended purpose. 
For example from ETC: 

> Disclaimer: The ETC Safety cable P/N 7060A1022, is to be used as a safety device for ETC lighting fixtures only. It should not be used for rigging or lifting any items or people and should not be used under tension.


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## Dionysus (Dec 16, 2019)

NO not at all. Those fast fold screens should NOT be suspended in this way. This is endemic of people who don't know well enough or don't care enough to do proper and safe rigging.


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## egilson1 (Dec 16, 2019)

Someone texted me the other day asking what the WLL of a lighting safety was. I had 2 answers.

1) The legal answer is one lighting fixture.
2) In my destructive testing the clip fails before the wire rope and that force is more than one lighting fixture, even the big wiggly ones.


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## Dagger (Dec 17, 2019)

I totally agree with that main use of a lighting safety and only use it for that purpose but to debate
" rules that are acceptable to be broken "

I read tests have shown that lighting safetys on a straight pull will break ~ 1500lbs (5:1 ~300lbs) 
and in basket it breaks at ~2900lbs (5:1 ~590lbs)

So if the object to be hung is within those numbers can it be argued that it is okay to to hang of safetys.


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## bobgaggle (Dec 17, 2019)

egilson1 said:


> even the big wiggly ones.





Nic said:


> I have never seen a safety cable rated for overhead lifting.



Haven't we agreed that "overhead lifting" applies to things that move? Either running rigging or static lines attached to a pipe that's attached running rigging? I'm not making an argument for the use of safeties as the primary rig, but OP is talking about a dead hang. Want to get the nomenclature right


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## BillConnerFASTC (Dec 17, 2019)

bobgaggle said:


> Haven't we agreed that "overhead lifting" applies to things that move?



I agree, though might add "vertically". I don't consider a dead hung curtain track to be overhead lifting by virtue of the movement. Any load that is raised and lowered at anytime over heads of people. 

I have made a case that a load that is moved vertically is not overhead lifting when the space under it is not occupiable. An acoustic banner where people are prevented from being under it.


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## JChenault (Dec 17, 2019)

egilson1 said:


> Someone texted me the other day asking what the WLL of a lighting safety was. I had 2 answers.
> 
> 1) The legal answer is one lighting fixture.
> 2) In my destructive testing the clip fails before the wire rope and that force is more than one lighting fixture, even the big wiggly ones.



Putting on my stupid hat here. I don’t think I have seen this discussed.

If a clamp failed catastrophically, it seems there would be a shock load on the safety that could apply more force than the clip could handle.

Is there any data that supports a double wrap of the safety for heavier fixtures? If so is there a definition of heavy enough to double wrap?

By double wrap I mean go twice around the pipe/yoke so the shock load would be reduced.


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## derekleffew (Dec 17, 2019)

Here's what I teach:
For conventionals, single wrap, enough slack to focus any direction.
For movers, double wrap, and/or as little slack as is practical, to shorten shock load distance.
A twelve pound Leko falling one foot may not exert much shock load, but a fifty pound mover might.
While not proud of it, I've used lighting safeties to hang fast-fold screens, provided they're in good condition and the clips are working properly. Beats tieline. Or zip ties.


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## Dagger (Dec 17, 2019)

derekleffew said:


> Here's what I teach:
> For conventionals, single wrap, enough slack to focus any direction.
> For movers, double wrap, and/or as little slack as is practical, to shorten shock load distance.
> A twelve pound Leko falling one foot may not exert much shock load, but a fifty pound mover might.
> While not proud of it, I've used lighting safeties to hang fast-fold screens, provided they're in good condition and the clips are working properly. Beats tieline. Or zip ties.



Properly swaged aircraft with verlocks?


I noticed lighting safetys are swaged differntly than normally would on aircraft cables. 
Reason?


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## egilson1 (Dec 17, 2019)

JChenault said:


> Putting on my stupid hat here. I don’t think I have seen this discussed.
> 
> If a clamp failed catastrophically, it seems there would be a shock load on the safety that could apply more force than the clip could handle.
> 
> ...



A safety that is in a loop already has double the capacity that if it was in a strait line. 


Dagger said:


> Properly swaged aircraft with verlocks?
> 
> 
> I noticed lighting safetys are swaged differntly than normally would on aircraft cables.
> Reason?



the tool used to make the compression is a wide jaw that requires only one compression. more like what you see on a flemish eye. thats why it looks different.


Dagger said:


> I totally agree with that main use of a lighting safety and only use it for that purpose but to debate
> " rules that are acceptable to be broken "
> 
> I read tests have shown that lighting safetys on a straight pull will break ~ 1500lbs (5:1 ~300lbs)
> ...



1/8" wire rope has a MBS of 2000lbs. I break a lot of it, domestic and imported. Almost all of the time it fails over the MBS. For a lighting safety it's the clip that is the issue. Want the ultimate lighting safety? replace the clip with a shackle.


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## Dagger (Dec 17, 2019)

How to calculate shockload? 

And if the safety is double wrapped the fall distance is shorter therefore shockload is lower


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## Dagger (Dec 17, 2019)

For argument of right wrong when see someone use lighting safetys on jobsite. It isnt wrong if within load capacity . - It is " perfectly and acceptable rule to be broken "


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## JAC (Dec 18, 2019)

Dagger said:


> How to calculate shockload?



It's not too difficult IF you know the weight (fairly easy to determine), the distance it falls (fairly easy to determine), and the stopping distance (tougher to determine - not impossible but probably not info that you have at your fingertips either).
For a fixture that falls onto a safety cable the stopping distance is very small, so more shock load than you might think.


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## Dagger (Dec 18, 2019)

Stopping distance small = more shockload?


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## Dagger (Dec 18, 2019)

So double wrapping a safety on moving lights to decrease fall distance is incorrect. ?


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## JAC (Dec 18, 2019)

Dagger said:


> Stopping distance small = more shockload?


Sure. Imagine if the safety cable was a giant rubber band that could stretch out four or five feet before the fixture gradually came to a complete stop. Less shock, no? Same principle as shock-absorbing fall protection.


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## Gobokat (Dec 18, 2019)

JAC said:


> Sure. Imagine if the safety cable was a giant rubber band that could stretch out four or five feet before the fixture gradually came to a complete stop. Less shock, no? Same principle as shock-absorbing fall protection.



Um, @JAC, I think you're missing an important point about fall arrest lanyards - they're sewn with "shock loops" (for lack of a technically correct term) that break and increase the length of the lanyard, thereby absorbing energy and trying to lessen the eventual shock of the 'arrest' from the harness wearer.
A safety cable, as you might note, is simply a piece of wire rope. When the end of the travel is reached the load is arrested and all force is taken immediately by the connection points. 
So, since F=ma, and our mass is constant, the only way to lessen force is to reduce acceleration. Acceleration is reduced by reducing the distance traveled (you can't go as fast from zero traveling 10 feet as you can traveling 100 feet) so the shorter you can make the travel of the fixture falling the less your shock load will be. The analog to this in fall arrest would be the retractable lanyards which lock travel after an inch or two. They don't try to brake and slow the travel over 6 feet, they lock within inches. less travel = less force.


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## Dagger (Dec 18, 2019)

Longer the free fall distance the heavier the object?

Example A 5/ 8 nut falling from 10ft vs 50t. 
50 ft fall will generate more force . ..

Am i thinking completely wrong here?


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## Dagger (Dec 18, 2019)

The safety shorter = less force imo


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## Gobokat (Dec 18, 2019)

Dagger said:


> The safety shorter = less force imo



I tend to agree - 
for example: 12 pounds falling 1 foot is 24 pounds of force, whereas 12 pounds falling 6 feet is 84 pounds of force. (more or less)


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## JAC (Dec 18, 2019)

Not thinking wrong, that's why fall distance is an important part of the shock load equation. But so is the force of the stop. A more gradual stop equals less shock load. The question wasn't, "will there be a shock load on a safety cable," but, "how is shock load calculated?"


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## Gobokat (Dec 18, 2019)

JAC said:


> Not thinking wrong, that's why fall distance is an important part of the shock load equation. But so is the force of the stop. A more gradual stop equals less shock load. The question wasn't, "will there be a shock load on a safety cable," but, "how is shock load calculated?"



The simple answer to your questions is to use the simple F=ma formula, but it gets complicated with a shock absorbing lanyards in fall arrest systems because they're meant to change the "a" part of the equation by the way they're sewn. If you want to play around with different deceleration time scenarios try the calculator on this page -




Calculate the force of a fall while using the fall protection force calculator

Use our free fall protection force calculator to determine the force generated on the body when using fall protection.



wilmes.co





And for what it's worth, there isn't enough elasticity in a wire rope type safety cable to count as any appreciable deceleration so your falling lighting fixture is pretty much straight F=ma calculation.


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## eadler (Dec 18, 2019)

Gobokat said:


> I tend to agree -
> for example: 12 pounds falling 1 foot is 24 pounds of force, whereas 12 pounds falling 6 feet is 84 pounds of force. (more or less)


correction: *stopping* after falling. 

12 pounds falling is under a (basically) constant 32 ft/s/s acceleration (well, until you reach terminal velocity) and thus the falling force is constant. F = m * g. The mass and acceleration aren't changing while it's falling. 

The difference is that the safety cable is only going to deflect so much and that proportion (and proportion of time - the math is easier with time than distance) is different over the longer distance. I'll leave this calculation as an exercise for the reader but suffice it to say falling farther causes a higher velocity when under constant acceleration and thus the acceleration back to not moving* is going to be quite different. 

(I did do rough terminal velocity math on the aforementioned 5/8 nut but it seems by my quick math it won't reach terminal velocity until it has fallen over 130 feet, more than the 10/50 split suggested)

*ok, it's probably going to bounce around for a while. Don't try this at home (well, unless this testing is the kind of thing you do for a living -- in that case, please do and post youtube videos with all the math too!)


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## JAC (Dec 18, 2019)

Sheesh. Again, just addressing the question that was asked, which was, "How is shock load calculated?" Weight, fall distance and stopping distance all factor into it.
But I'm just some schmuck on the internet; if you really want to know, Jay Glerum, Delbert Hall, and Harry Donovan all have excellent books that will explain it better than I could.


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## Dagger (Dec 18, 2019)

Another example. Please help me with the calculations

I have seen ona gig where a motor chain fall out of a bag while it was being raised .

The motor was hung invert 100ft up with gac in a basket configuration. When the chain was being raised approximately 80ft up in the air the chain fell out of the bag. ( wrong size chainbag ).

What is the shockload?


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## egilson1 (Dec 18, 2019)




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## Crisp image (Dec 19, 2019)

egilson1 said:


> Want the ultimate lighting safety? replace the clip with a shackle.


Or a Maillon Rapide. A great alternative and very secure.
EDIT: Corrected spelling


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## derekleffew (Dec 19, 2019)

Crisp image said:


> Or a Mallion Rapide. A great alternative and very secure.


I had to look that up (and not just because you spelt it wrong).


Maillon Rapide

Here in the US, we'd call that a quick-link, and endlessly debate its appropriateness.
.


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## TheaterEd (Dec 19, 2019)

Dagger said:


> Stopping distance small = more shockload?



Correct

Dagger said:


> So double wrapping a safety on moving lights to decrease fall distance is incorrect. ?



Incorrect. You are combining stopping distance and fall distance. 
Fall distance = how far the fixture falls before the safety engages and it begins to slow down
Stopping distance = How far the cable 'stretches' before stopping the fixture. The longer that distance is, the more time it will take.

Force = Mass * Acceleration
Acceleration = Change in Velocity / Time

In our case here, Acceleration = slowing down the fixture from free fall
The longer the time it takes to slow down, the lower the acceleration will be. Lower Acceleration = lower force.


Dagger said:


> The safety shorter = less force imo



Correct.


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## Dagger (Dec 19, 2019)

Stopping distance- " stretch" .
Is that why for climbing dynamic ropes should be used. ?


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## Dagger (Dec 19, 2019)

egilson1 said:


> View attachment 18985



Shockload force = ?
LOAD = 150lbs (CM motor 125' chain ~150lb)

Free fall distance = 80'
Stopping distance= ??? ( it fell 80'and came to a stop- so hoe to find value for that??)

Also back to LOAD: use only the weight that fell? Which is 80'of chain , idk maybe ~40 lbs or use the entire weight of rhe motor?

And where is the shock load applied to ? I am thinking it is applied to the shackle on top ( which is making the connection to gacflex)

@egilson1 @TheaterEd @RonHebbard @RonaldBeal @porkchop @What Rigger?
@JAC
@bobgaggle 
@BillConnerFASTC 
Etc


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## Crisp image (Dec 20, 2019)

derekleffew said:


> I had to look that up (and not just because you spelt it wrong).
> 
> 
> Maillon Rapide
> ...


No matter what you call them they have a rating which is MBS not WLL or SWL. As long as they are done up correctly they are good but must be used as designed. 
I have safety cables in the PAC that I work at with them. The beauty of them is that it takes multiple operations to open them and there is no chance of roll out. 
If I had a choice of these and some of the clips on other cables I would choose theses everytime. 

Regards
Geoff


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## BillConnerFASTC (Dec 20, 2019)

If you only finger tighten repair links normal building vibrations can open them. Unlike a screw pin shackle, no way to mouse these.


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## Dionysus (Dec 20, 2019)

BillConnerFASTC said:


> If you only finger tighten repair links normal building vibrations can open them. Unlike a screw pin shackle, no way to mouse these.


Also note that this is also why you should ALWAYS face them so that they "close with gravity" this way you* help *prevent them vibrating completely open.


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## BillConnerFASTC (Dec 20, 2019)

Dionysus said:


> Also note that this is also why you should ALWAYS face them so that they "close with gravity" this way you* help *prevent them vibrating completely open.


Good thought but I'd find it a little impractical to inspect and see at distance - like mousing can be seen - and if it bounced or the safety cable loop is rolled/rotated the link would be upside down.

I'm in a minority on the safety cable on lights - I don't loop through yoke but cinch around the eye on the fixture (or around the pipe) and clip to itself (or to the eye). The yoke to pipe doesn't protect from what I think is the most common failure point - the yoke bolt. And IIRC the mouse requires all accessories - color frames, top hats, etc. -to also be saftied. I've only ever seen a barn door fall. YMMV

1/16"gac has a breaking strength of 480 pounds so 60 SWL if the swages and hook is rated for 100%? Put two on movers.


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## RonHebbard (Dec 20, 2019)

BillConnerFASTC said:


> Good thought but I'd find it a little impractical to inspect and see at distance - like mousing can be seen - and if it bounced or the safety cable loop is rolled/rotated the link would be upside down.
> 
> I'm in a minority on the safety cable on lights - I don't loop through yoke but cinch around the eye on the fixture (or around the pipe) and clip to itself (or to the eye). The yoke to pipe doesn't protect from what I think is the most common failure point - the yoke bolt. And IIRC the mouse requires all accessories - color frames, top hats, etc. -to also be saftied. I've only ever seen a barn door fall. YMMV
> 
> 1/16"gac has a breaking strength of 480 pounds so 60 SWL if the swages and hook are rated for 100%? Put two on movers.


 And GAC-Flex Slings? Anyone care to veer down that road?? 
Toodleoo! 
Ron Hebbard


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## Crisp image (Dec 20, 2019)

BillConnerFASTC said:


> If you only finger tighten repair links normal building vibrations can open them. Unlike a screw pin shackle, no way to mouse these.


TBH never had one vibrate open on me but we are always changing the plot depending on the show. Still better than a non protected clip IMO.


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## RonHebbard (Dec 20, 2019)

Crisp image said:


> TBH never had one vibrate open on me but we are always changing the plot depending on the show. Still better than a non protected clip IMO.


Since we're veering down the path to the tightening of Quick-Links / Maillion Rapides; an area amateur group, a group where many of the performers were teachers, from kindergarten through colleges to universities and (in their minds) beyond with the bulk of their builders, sound and lighting members being their students; many afflicted with SEVERE Queen / King Of THE Booth syndrome:
The "teachers' were of three minds:
- Find the BIGGEST wrench you can muster and strip the threads of every shackle, turnbuckle, and quick-link on the premises.
- Leave them finger tight.
- And - or; they're only students, phuqu'em; let's go to the bar and drink ourselves silly!!! (then drive home [that'll teach 'em!] )

Consequently I'd periodically visit and light a production; often when voluntold by my wife (but that's a whole different story)
Hence many students grew to believe that finger tight, or looser, fittings actually magically tightened themselves over time given enough time between productions. Obviously, what other explanation could make sense: Little Johnny lit a show and knows he left things finger tight, only to return next semester and find he needed to clamber back down and climb back up, an un-tethered wrench (or two [who knows what sizes may be required]) in one hand as he scampers up their rolling set of stairs.
Who'd ever have thought some guy from Stratford would drop by and be IDIOT enough to actually bring his own 8" Crescent (with a 'silly' lanyard attached) wrench with him to actually touch his wrench, lightly, to each and every overhead fitting that would only need to be loosened a few weeks or months, later. Toodleoo!
Ron Hebbard


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## BillConnerFASTC (Dec 20, 2019)

Crisp image said:


> TBH never had one vibrate open on me but we are always changing the plot depending on the show. Still better than a non protected clip IMO.


We are trying to protect against 1 in hundreds of thousands.


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## josh88 (Dec 21, 2019)

Crisp image said:


> TBH never had one vibrate open on me but we are always changing the plot depending on the show. Still better than a non protected clip IMO.



I HAVE found one hung and open and not just because someone forgot to close it when it was hung. That one, was enough for me to prefer something I can mouse, OR I'll tighten these down hard, which people don't like on the out, so its easy to go with a mouseable option like a shackle. Terrifying to see something held just with gravity and the fact that the gate wasn't open far enough at the time for it to slip free.


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## Dionysus (Dec 21, 2019)

josh88 said:


> I HAVE found one hung and open and not just because someone forgot to close it when it was hung. That one, was enough for me to prefer something I can mouse, OR I'll tighten these down hard, which people don't like on the out, so its easy to go with a mouseable option like a shackle. Terrifying to see something held just with gravity and the fact that the gate wasn't open far enough at the time for it to slip free.



I've found SEVERAL Quicklinks open after installation in my time. Always "upside down".


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## mbrown3039 (Dec 25, 2019)

Dagger said:


> I have seen safety cables being used to suspend for example da lite fast fold screens or chandeliers up to 200lbs. Acceptable to use safeties to actually hold the weight?



Whether a safety cable is technically capable of holding X weight is not the question you should ask yourself in this situation. The question you should be asking is "what happens when someone uses a piece of equipment in a way for which is has not been certified and/or approved by the manufacturer?"

The options are either "nothing" or "something." If "something" happens you now have two more options: "something small" (i.e., no one was hurt and nothing was damaged) and "something big" (someone WAS hurt and/or something was damaged). If something big happened and someone was hurt, how would you feel about that shortcut? How would the person injured (and only injured, hopefully) feel? How would their lawyer feel about it?

The form factor of the lighting safety is supper handy, but -- for Safety's sake -- go to your local rigging supply/safety shop and buy half-a-dozen 18", RATED stingers and shackles and set them aside for this purpose. best wishes, mike

PS - In the world of job site safety, if you add up enough "something smalls" they will eventually turn into "something big." Always. m


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## mbrown3039 (Dec 25, 2019)

BillConnerFASTC said:


> ....I don't loop through yoke but cinch around the eye on the fixture (or around the pipe) and clip to itself (or to the eye). The yoke to pipe doesn't protect from what I think is the most common failure point - the yoke bolt. And IIRC the mouse requires all accessories - color frames, top hats, etc. -to also be saftied.....



^^^^ This is the correct way. Everyone read this, please. Wrapping the safety around the batten and the yoke only keeps the yoke from falling (and only momentarily, at that, bacuse sooner or later it will roll out of the safety). You have to cinch around the batten and clip to the body of the fixture....I am still amazed by how often I see it done the wrong way. m


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## Ted jones (Dec 25, 2019)

Dagger said:


> I totally agree with that main use of a lighting safety and only use it for that purpose but to debate
> " rules that are acceptable to be broken "
> 
> I read tests have shown that lighting safetys on a straight pull will break ~ 1500lbs (5:1 ~300lbs)
> ...




My issue with your testing is not how you tested it. It is that you tested one from Brand "A" and that the next guy is using one assembled by Brand "F". There are few safety cables with tags on them stating date and source of assembly. We have no idea who made YOUR assembly and how they made it. Nor do we know the source of the snap hook or if it is rated for any load at all. It may be rated to be a snap hook with no load rating. These things exist. 

Safety cables, even from reputable assemblers like Fehr, ETC, Altman, Versales, etc are all rated to catch a falling lighting instrument. They don't give you a working load otherwise. Purposely.

For overhead, I don't trust snaps like that one as they can be opened in use by the cable wrapping around it.

Just saying.

T


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## Dagger (Dec 26, 2019)

Dagger said:


> Shockload force = ?
> LOAD = 150lbs (CM motor 125' chain ~150lb)
> 
> Free fall distance = 80'
> ...




Based on information i looked up i found that 5/16 " load chain is 0.9 lb/ ft.

Load= 0.9x 80ft = 72 lbs

Information i have found on 
Stopping distance ( = stretch)

Elastic Stretch = weight x G factor/ d of rope square 
G factor = 0.0000140
D of rope 5/16 square = 0.0977

Elastic Stretch= 72 lbs x 0.0000140 / 0.0977
Elastic Stretch= 0.010317

Stretch = elastic stretch/ 100 x lenght of chain in inches

Length = 80' = 960"

Stretch= (0.010317/ 100) x 960
=0.0995 inches

Force= weight × (distance/stopping distance)+1
Force = 72 lbs x (80/0.0995)+1
=
57961.45 lbs (?????)

I dont think this can be correct . Isnt that way to high of a shockload. (?)


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## Kittin (Dec 27, 2019)

As far as not paying attention to your rigging going the right way, etc....we had a touring Broadway show in our house a year or two ago and one of their people didnt pay attention to which way their shackles were going when they were raising up the ENTIRE dimmer cart to hang suspended (by motors) for the show a little ways onstage of the rail. My husband is a rigger and noticed a....2500+lb cart shimmying and managed to push our theatre's TD out of the way with inches to spare before it came crashing down, putting holes through the floor and denting the metal on the rail. The whole 100+ workers on stage came to a compelte halt and silence. 
So ya, id rather make sure anything going in the air is fixed correctly.

Ive also gone into a college and found the DJ bar LEDs used for cyc lights hung with TIE LINE....only tie line. In a shoelace bow. I came in after the college did a performance to run a special event, wondered why their cyc lights were hanging crooked....much to my surprise, there were no clamps nor safety cables attached. I called my boss and when he told me it wasnt our responsibility, I told him if he wasnt going to pay my coworker and I for the 2hrs we had to spend attempting to figure out a way to properly hang them, screw him. But that I knew about it and was NOT going to allow it to stay that way....especially since the following week was the 2nd-8th graders summer camp that would use the stage. 

I tell my crews the only time they will ever hear me yell at them is if they are doing something unsafe/for safety reasons. Mistakes can be fixed, slacking on safety takes lives, and you never hear of anything falling up.


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## danTt (Dec 27, 2019)

Dagger said:


> Properly swaged aircraft with verlocks?



Unless somethings changed, verlocks are not rated for overhead lifting.


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## RonHebbard (Dec 27, 2019)

Kittin said:


> As far as not paying attention to your rigging going the right way, etc....we had a touring Broadway show in our house a year or two ago and one of their people didnt pay attention to which way their shackles were going when they were raising up the ENTIRE dimmer cart to hang suspended (by motors) for the show a little ways onstage of the rail. My husband is a rigger and noticed a....2500+lb cart shimmying and managed to push our theatre's TD out of the way with inches to spare before it came crashing down, putting holes through the floor and denting the metal on the rail. The whole 100+ workers on stage came to a compelte halt and silence.
> So ya, id rather make sure anything going in the air is fixed correctly.
> 
> Ive also gone into a college and found the DJ bar LEDs used for cyc lights hung with TIE LINE....only tie line. In a shoelace bow. I came in after the college did a performance to run a special event, wondered why their cyc lights were hanging crooked....much to my surprise, there were no clamps nor safety cables attached. I called my boss and when he told me it wasnt our responsibility, I told him if he wasnt going to pay my coworker and I for the 2hrs we had to spend attempting to figure out a way to properly hang them, screw him. But that I knew about it and was NOT going to allow it to stay that way....especially since the following week was the 2nd-8th graders summer camp that would use the stage.
> ...


 *@Kittin* In 1990, I was with a Canadian / American co-pro of "Buddy Holly The Musical" in Broadway's Shubert when a fire erupted in the 'Music Box' or 'Jewel Box' (if memory serves) around the corner where a tour of 'Lettice and Lovage' was parked with Maggie Smith and Maggie Tyzack. 

48 slot / 96 x 2.4 Kw racks were flown from the grid by Load Stars basketed to the grid with Spansets. The NYFD were NOT favorably impressed by dimmer racks plummeting down through the dense smoke when the Spansets melted due to the intense heat at grid height. I believe this was the fire that resulted in the development of GACFlex fire tated Slings. 
Toodleoo! 
Ron Hebbard


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## Kittin (Dec 27, 2019)

RonHebbard said:


> *@Kittin* In 1990, I was with a Canadian / American co-pro of "Buddy Holly The Musical" in Broadway's Shubert when a fire erupted in the 'Music Box' or 'Jewel Box' (if memory serves) around the corner where a tour of 'Lettice and Lovage' was parked with Maggie Smith and Maggie Tyzack.
> 
> 48 slot / 96 x 2.4 Kw racks were flown from the grid by Load Stars basketed to the grid with Spansets. The NYFD were NOT favorably impressed by dimmer racks plummeting down through the dense smoke when the Spansets melted due to the intense heat at grid height. I believe this was the fire that resulted in the development of GACFlex fire tated Slings.
> Toodleoo!
> Ron Hebbard



Oh, it was a large cart....like larger than a set cart....one that held all the dimmer racks, pretty much it was all of dimmer beach/LX's work arwa on a cart so it could fly and stay airborne, allowing show LX to take care of whatever was needed by climbing up. So not at all close to the grid height, plenty of air flow around it. The had at least 4 motors, I wish I could remember if they used gak or what. Id ask my husband if he were in town right now. 
They flew them to give room enough on stage for a pretty large production (23+ trucks maybe? As a hint...prior to the productions stop, the house had to have a new I-beam put in to carry weight of a somewhat notorious chandalier). Another one that was less weight but equally as large was automation's cross stage flying cart which I believe was actually the stage/show spot for one of the automation guys. Not my side of the stage and I only checked power and paid attention to my guys, so I wasnt paying much attention to their guys in the air after noting that everything was leashed. I saw a couple of them up there a lot though.

It wasnt the first production that has flown a large portion of a department for the show. We have a decent amount of backstage work area, but so many big shows need a heck of a lot more than we have. We honestly removed every bit of house gear that we would not be using including shell ceilings, meat racks, and anything else we could to make room enough for their production to have just about what they required in space. Took 3 days of prehang, and we dont keep a house plot hung or etc, so none of that was removing lights and cabling other than removing them from the ceiling of the shell. Was 4 days of load in, I believe, and after the matinee show 2 weeks later (4pm maybe?), we worked until about 11am the next morning on the load out. Then came back the following day for restore. So, although I dont recall the exact number of trucks, it was a lot of gear brought in. 

I wish I could give the exact way the cart was flown, from my limited memory of it, I think the deduction was that someone didnt pay attention to how the shackles were attached, making it slip and kaboom. I know it was done correctly the second time, when they got it up, and we had no more problems after that, or on the second one that flew. Honestly, the most vivid memories were of watching my husband and the TD walking by the rail, under it and one of my dept guys being on the upstage side near the rail when it came crashing down. Then the complete silence until I saw my husband and the trembling TD standing about a foot away from where it crashed, and my guy on the other side trying to hold it together. Once I took a breath, I ended up breaking the complete silence by yelling at my husband for always trying to terrify me...jokingly. I'm scared of heights, so bad that when I started back again about 5 years ago after a small hiatus in marketing, I could go 2 steps up a ladder and started freaking out....the first time I climbed the ladder to the pin rail, I was so terrified that I destroyed my back so bad I couldn't lift my arms straight out even halfway to making a line with my shoulders. Now I'm a lot better, even have my own harness and have done some rock climbing gym stuff. I dont freak out anymore, but id never want to do what my husband does, and he was a lot cockier about what he was willing to do before he lost 3 rigger friends in one year to accidents and saw his best friend ride a genie lift down from 30' to deck when someone decided a cable was okay to run over when the lift was in the air. Not to say i dont trust my husband to do his job, but he's the type of guy who will put himself in a dangerous position that HES comfortable with if it might help/save a colleague. And by the grace of God, he was able to push our TD fast enough (TD is about 6" taller and has 75lbs on him) when he noticed the shimmy, since no one else noticed and it was incredibly sudden, the TD didnt know what was going on other than being pushed and told to move, move, move... Then it crashed down.
It was user error, not a failure of gear or under rated materials being used. Just lucky that everyone got out. I spent about an hour after the accident fielding "are you okay" queries from everyone, since I went right back to work (I was just like, hello, now we're going to be running behind since show crew all had to fix their cart). TD needed a bit before he came out of his office after that. I let my luckily-not-flattened elec take a minute to smoke and reflect on his decision to move out of the way instead of trying to save a piece of gear, and my husband went to explain the whole thing to the steward (no idea after that).

I am *not* a huge fan of flying something that large and heavy above my head for the entirety of a show. But needs must. If I could simply build a giant vending machine for everything into the wall, I would. But not entirely practical. Nor are conveyer belts or sitting everything outside and hoping to avoid rain. So until I figure someting else out, I'm completely sans inspiration to avoid large heavy things hovering above my head


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## JonCarter (Dec 27, 2019)

OK guys, now we've beaten to death the safety cable issue for the safety cable holding the _instrument yoke_ to the _hanging pipe_. What about the need for a safety cable holding the _instrument_ to the_ yoke_?? How about another one holding the _lamp cap_ to the _rest of the instrument_? And, OMG, what about the _gel frame???_ (Where do we stop with this?)

In 50 years I and my crews have hung instruments "down," "out" and "up" and never had a C clamp break or yoke bolt break or come undone. (Or, for that matter, _seen_ a safety cable.) If your equipment is properly maintained and properly installed this is all moot. And if it isn't, you have serious crew training issues.


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## BillConnerFASTC (Dec 28, 2019)

I have seen yoke bolts fail. But we incorporate redundancy in many things for safety.


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## danTt (Dec 28, 2019)

JonCarter said:


> In 50 years I and my crews have hung instruments "down," "out" and "up" and never had a C clamp break or yoke bolt break or come undone. (Or, for that matter, _seen_ a safety cable.) If your equipment is properly maintained and properly installed this is all moot. And if it isn't, you have serious crew training issues.


Just to clarify--you haven't seen a safety cable in your 50 years of hanging instruments?

I'm going to go ahead and stay on this side of the continental divide


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## RickR (Dec 29, 2019)

Yoke have two bolts holding the body. My understanding is that that built in redundancy relieves us of body safeties. And that yokes are not prone to sudden failure!


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## BillConnerFASTC (Dec 29, 2019)

My experience was one stripped and fell out, the other side snapped with impact laid. But long ago with much less well designed fixtures.


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## JChenault (Dec 29, 2019)

I never had a clamp fail. What I did occasionally have was the lens on the Altman fresnel unclip and swing down. Sporty if you had a barn door in the fixture.


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## Chase P. (Dec 30, 2019)

I've seen exactly one c-clamp fail, and it was due to an instrument being struck by a passing flown scenic piece.

We don't just have to account for the shock load of a falling instrument, but also try to allow for the potential force from an object dragging the instrument with it. Obviously we work to avoid situations like the one I mentioned, but I'm sure we all have examples of a flyspace so packed that breasting lines and special cues to help dodge obstacles have been necessary.

I'm of two minds on the clips on safety cables: One, I'd prefer that they have a definitive open/close, not just a pear clip that can open accidentally. Two, they still have to be easy enough to operate that they don't get forgotten or skipped, and they need to be able to be operated one handed for the times we have weird hang positions.

I've seen dog clips and snap clips used, and I hate it. Also, I hate when they're swaged with pointy bits of wire sticking out. That can pass muster on cables attached to scenery or battens, but not on a device that we have to touch every time we move an instrument. If you've ever been stabbed bloody by one, think of all the nasty grime floating around the places we work. It's not sanitary, and it's asking for an infection and a workplace injury claim. If you're making cables for any reason, try to not leave booby traps for your co-workers and future you.

Has anyone found the holy grail of safety cables: rated, good clip, not stabby, affordable? 

Quick story and I'll end my PSA:

I knew a guy who worked the seasonal department at a big box hardware store with a blue logo. He got a paper cut from a cardboard box of cheap Christmas crap from overseas. He thought nothing of it, it's a paper cut after all. It got infected with some virulent bacteria from the country of origin, and he wound up having half a finger on a dominate hand amputated. Having not filed an accident report, the corporation tried to weasel out of paying for it. 
Take your injuries seriously, and work to prevent them, no matter how small. I carry e-tape for lighting hangs, and wrap over any safety cable stabbers I find.


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## derekleffew (Dec 30, 2019)

Chase P. said:


> Also, I hate when they're swaged with pointy bits of wire sticking out. That can pass muster on cables attached to scenery or battens, but not on a device that we have to touch every time we move an instrument. If you've ever been stabbed bloody by one, think of all the nasty grime floating around the places we work. It's not sanitary, and it's asking for an infection and a workplace injury claim. If you're making cables for any reason, try to not leave booby traps for your co-workers and future you.
> ...
> Take your injuries seriously, and work to prevent them, no matter how small. I carry e-tape for lighting hangs, and wrap over any safety cable stabbers I find.


I'm sure @What Rigger? @egilson1 @Ted jones _et al_ will correct me if I'm wrong, but I believe best practice when swaging is to leave a minimum length of wire rope, equal to the cable's diameter, sticking out of the swage upon completion of crimping. Another good reason for not making one's own cables.


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## Chase P. (Dec 30, 2019)

derekleffew said:


> I'm sure @What Rigger? @egilson1 @Ted jones _et al_ will correct me if I'm wrong, but I believe best practice when swaging is to leave a minimum length of wire rope, equal to the cable's diameter, sticking out of the swage upon completion of crimping. Another good reason for not making one's own cables.


I'd love to know the actual answer to that, because it's entirely possible that my training in college was incomplete. We were told no excess sticking out.

Whatever the answer, if excess is necessary in a situation, I wrap that up with e-tape, or I shrink tube the end of the cable if I know it'll be exposed.


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## BillConnerFASTC (Dec 30, 2019)

One article. https://www.e-rigging.com/How-to-Select-and-Use-Swage-Sleeves. Two diameters this says.

Was not where I could listen to numerous YouTube videos but all showed a tail.

Shrink tube.


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## RickR (Dec 31, 2019)

Just to show how training can vary;
I was taught 2 sleeves, the 2nd to contain the stabby ends.


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## derekleffew (Jan 1, 2020)

RickR said:


> Yoke have two bolts holding the body. My understanding is that that built in redundancy relieves us of body safeties.


Sorry, not buying that argument.

derekleffew said:


> My EC Parellisphere has a non-forged eye-bolt just behind the top shutter, 'course it weighs about 30 lbs. It may have been the first theatrical fixture to have an attachment point. Film/TV fixtures (Mole-Richardson, Bardwell-McCallister, et al.) had them for years before that.


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## Chase P. (Jan 1, 2020)

Bill:

This was extremely informative. Despite what I thought was good training in college, I’ve been doing a number of things wrong. Not as wrong as some of the rigging I’ve seen over the years, but enough.

Thanks for the link!


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## What Rigger? (Jan 3, 2020)

derekleffew said:


> I'm sure @What Rigger? @egilson1 @Ted jones _et al_ will correct me if I'm wrong, but I believe best practice when swaging is to leave a minimum length of wire rope, equal to the cable's diameter, sticking out of the swage upon completion of crimping. Another good reason for not making one's own cables.


When I worked for (major flying company) and was trained to make compressions, I was told "If there's enough tail sticking out that you bleed when you press your thumb down on it and twist, that's too much." And I was literally made to do this. I got really good, really fast. 

My current employer documents that the tail shall equal the diameter of the wire rope being pressed. 

"Opinions vary"-Dalton, _Road House_


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## BillConnerFASTC (Jan 4, 2020)

Nicopress instructions: https://www.google.com/url?sa=t&sou...FjABegQIBBAB&usg=AOvVaw0tj4qJ5L28On97qCxUjcoE

Protrude slightly after crimping.


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## Crisp image (Jan 4, 2020)

I was always told that the ends should be just visible outside the crimp because you could see that the cable went all the way through the ferrule. This is for rigging slings and not necessarily the safety cables.
Regards
Geoff


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## TimMc (Jan 5, 2020)

The NicoPress guide says the tail should protrude by 2x the wire rope diameter. I agree that heat shrink would be preferable to gaff tape or vinyl tape to prevent handling injuries.


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## BillConnerFASTC (Jan 5, 2020)

TimMc said:


> The NicoPress guide says the tail should protrude by 2x the wire rope diameter. I agree that heat shrink would be preferable to gaff tape or vinyl tape to prevent handling injuries.


Can you link that since the Nico instructions I linked above don't say that? Thanks.

There is an electrical tape - 3m 88 maybe - thick and really sticky and stretchy - that works ok. And some have coated with epoxy - pretty easy and efficient with the syringe systems.


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## TimMc (Jan 5, 2020)

BillConnerFASTC said:


> Can you link that since the Nico instructions I linked above don't say that? Thanks.
> 
> There is an electrical tape - 3m 88 maybe - thick and really sticky and stretchy - that works ok. And some have coated with epoxy - pretty easy and efficient with the syringe systems.



IIRC I have the printed document at the office, I'll look for it tomorrow.


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## bobgaggle (Jan 7, 2020)

bobgaggle said:


> I have seen ona gig where a motor chain fall out of a bag while it was being raised .
> 
> The motor was hung invert 100ft up with gac in a basket configuration. When the chain was being raised approximately 80ft up in the air the chain fell out of the bag. ( wrong size chainbag ).
> 
> What is the shockload?



This isn't a simple calculation. As the whole pile of chain is falling, its getting lighter and lighter, as link by link is stopped by. The free falling mass is continuously changing. So if you've got 80 feet of chain that gets dumped and starts to fall, in one second its only 48 feet of chain falling. Your GAC basket is taking more load the whole time the chain is in free fall, not just when it "hits" the bottom


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## TimMc (Jan 7, 2020)

TimMc said:


> IIRC I have the printed document at the office, I'll look for it tomorrow.


Of course now that I'm looking for it, I can't find it. In the mean time I'll defer to the PDF that was posted.


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## egilson1 (Jan 7, 2020)

Also remember that the “shock load” equation is for an object in free fall. A chain running out of a bag is not in free fall, but rather at a changing velocity as the load changes, and as the length changes.


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## eadler (Jan 13, 2020)

RickR said:


> Just to show how training can vary;
> I was taught 2 sleeves, the 2nd to contain the stabby ends.


As was I. Is there any issue with this way? 
That is you have the 'first' (at thimble/loop) crimp for function and another farther down (away so you can see that the cable went all the way through and so there's no deformity) crimped afterwards right at the end so it doesn't stab anyone.


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## BillConnerFASTC (Jan 13, 2020)

I have heard two sleeves weakens they eye but could be folk lore. Of course two are usually required for a splice.


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