what in the world

[Fulthrotl]

Yes this is for stage equipment he wants me to supply the camlocks on a panel from the breaker panel. so do I run conduit to a j box and mount these camlocks to the front of it? he wants 200Amps. thanks for the help so far.

2/0 is normally what is used for 200 amp tails on trade shows.
not judging, just reporting facts. they'll use 3 4/0's in parallel for a megawatt.
true story. they used fans. lots of 'em. they core soaked a half megawatt
dry type transformer, and it was damaged enough to require replacement...
(CES, las vegas)

back to the dimmer panel feed.....
use 4/0 welder cable for the whips. neutral and ground are reversed,
unless it's west coast lighting... they do things dif'rent.....
pipe to 12x12x8 box, unpunched box, pull your own holes, and use
kellums for the tails. any concentric knockouts will be destroyed in
72 hours in a show environment.... use unpunched boxes.

anyway, thats how it's done around these parts.... i did trade shows
for over 2 years straight.... let me restate that.. i did trade shows
continuously for two years... nobody can do them straight.... you go
into the bathrooms in the convention centers in those days, and it was
either a plumbers convention, from the sound of the blowtorches, or
their was some serious drug abuse going on....

 

[zbang]

. they core soaked a half megawatt
dry type transformer, and it was damaged enough to require replacement...
(CES, las vegas)

Hmm, I used to know some of the IBEW guys at the LVCC and they were better than than. Was it one of the other venues? (OTOH, LVCC is the only place that had boost transformers already mounted on hand trucks. The line voltage could easily sag below 200v, and sometimes below 195v.)

back to the dimmer panel feed.....
use 4/0 welder cable for the whips. neutral and ground are reversed,
unless it's west coast lighting... they do things dif'rent.....

Uh, use type SC cable, not welding, and even though I like the reversed N & G, and I'm originally an easterner, don't do that on the tails, just have a iaor of turnaround available.

Otherwise, the OP's rack is nothing surprising.

BTW, in my experience, the stage electricians are usually OK, it's the film production guys that use jumper cable clips.

 

[wireguru]

2/0 is normally what is used for 200 amp tails on trade shows.
not judging, just reporting facts. they'll use 3 4/0's in parallel for a megawatt.
true story. they used fans. lots of 'em. they core soaked a half megawatt
dry type transformer, and it was damaged enough to require replacement...
(CES, las vegas)

back to the dimmer panel feed.....
use 4/0 welder cable for the whips. neutral and ground are reversed,
unless it's west coast lighting... they do things dif'rent.....
pipe to 12x12x8 box, unpunched box, pull your own holes, and use
kellums for the tails. any concentric knockouts will be destroyed in
72 hours in a show environment.... use unpunched boxes.

anyway, thats how it's done around these parts.... i did trade shows
for over 2 years straight.... let me restate that.. i did trade shows
continuously for two years... nobody can do them straight.... you go
into the bathrooms in the convention centers in those days, and it was
either a plumbers convention, from the sound of the blowtorches, or
their was some serious drug abuse going on....

theres a chart molded into those leviton camlocs i posted a picture of. It says use 90deg C cable - 4/0 - 400A; 3/0 - 350A; 2/0 - 300A; 1/0 - 260A. I have always used 2/0 SC @ 200A, not 300 :/

no more welding cable as of like 15 years ago. has to be type SC.

Explain the transformer going into saturation and bring ruined. Is that where the core becomes permanantly magnetized and the transformer doesnt transform anymore? (guessing here - i have no idea)

Youre 100% right in the last paragraph. I remember working a hair care convention in vegas, think it was 1996, last event in the hacienda before they blew it up. Anyways, our union stagehands (we had to have one union guy for every 2 of ours or something like that) refused to work (we would have prefered to pay them to just sit there, but they were the only ones allowed to do any physical work, all we could do was the tech and artistic work) -they refused to do any work until someone got them drugs. (i was thinking wait -its 1996 not 1986, but their gold chains and silk shirts thought otherwise) they literally sat on the ground and wouldnt move. finally paid them off to let us just do the work, one disapeared for a couple hours then they were all talking alot for the rest of the day.

 

[iwire]

now let me ask this, if somebody had 4 single wires hanging out of a disconnect with cam locs on the end wouldnt you have to cut slits inbetween the KO's to remove the eddy currents in the metal so it doesnt heat up?. i know the code requires this for seperate conductors entering seperate holes. i dont remember the article

Yes, but I have always run them out the same chase nipple.

 

[infinity]

Typically we will use these to supply theater lighting equipment. They're called company switches and have camlock connectors in the bottom of the switch or lugs behing that lower door to connect cables to. Although not visible this switch has both:

 

[bikeindy]

You need to provide a disconnecting means at the point you provide the cam locs. You can get disconnecting means with cam locs from some sources but I would probably just get a 200 amp disconnect and a set of panel mount cam locs, hubbell sells them.

Grainger has them.

http://www.grainger.com/Grainger/items/2XB50

how would you size the wire for the camlocs at 200 A Iwire? What size for grounding and grounded as well as the ungrounded? Thanks

 

[dbuckley]

Yep, thats a dimmer rack, kudos to iwire for spotting the Socapex mutipin connectors. It looks like about 1/3 of the rack is pictured, as you can just see the lid catch at the top edge of the picture on both sides. So I'm gonna stick my neck out a bit and say its about the right size for a standard 72 channel dimmer rack, with each channel 10A.

You want to install a company switch like the one pictured immediately above only more amps. Like a Lex 400A

Note double neutral camlocs on the company switches for 200% neutral rating Even though this rack has only one neutral cam.

Cables you rent or buy from your local production supply house.

Cables are (in rock and roll) frequently theoretically overloaded, because you dont spend the entire show with your finger on the "all on" button, but sometimes you do poke said button. So the supply has to be capable of the full load, as it'll trip off if it isn't, but the cables just warm up a bit during full on, and then cool off again when the load returns to normal, which is typically under 50% of the connected load. PoCo logic!

 

[pbeasley]

I've seen some great information in these posts. the one thing that has not been addressed..... are youproviding temporary connection, or are you providing a permanent setup that they can plug/unplug over and over. If this is a temporary setup, you may find it easiest to just rent fused disconnect from one of your local Stage and Studio lighting suppliers. If this is permanet, then I would suggest the 200A disconnect w/ gutter/box solution. If you build a box, keep at least 3" center to center on the panel mount connectors, I am a big fan of 5" (I hate skinned knuckles). Make sure you include the spring back metal covers mentioned earlier, and mount the connectors on the bottom, not the front face. Connectors should be mounted in order G-N-A-B-C or reversed, but do not put the Ground/Neutral (sorry, grounding/grounded conductor) on opposite sides of the hot legs (ungrounded conductors).

 

[electricalperson]

Yes, but I have always run them out the same chase nipple.

wouldnt that be a code violation? the terminals inside the disco will be supporting the conductors. unless they stick kellums grips on them

 

[cowboyjwc]

You see these all the time at carnivals and fairs and as iwire said on stages (concerts, movies, tv productions) they are usually fed from a generator or at least the ones I have seen are.

 

[Fulthrotl]

no more welding cable as of like 15 years ago. has to be type SC.

Explain the transformer going into saturation and bring ruined. Is that where the core becomes permanantly magnetized and the transformer doesnt transform anymore? (guessing here - i have no idea)

Youre 100% right in the last paragraph. I remember working a hair care convention in vegas, think it was 1996, last event in the hacienda before they blew it up. Anyways, our union stagehands (we had to have one union guy for every 2 of ours or something like that) refused to work (we would have prefered to pay them to just sit there, but they were the only ones allowed to do any physical work, all we could do was the tech and artistic work) -they refused to do any work until someone got them drugs. (i was thinking wait -its 1996 not 1986, but their gold chains and silk shirts thought otherwise) they literally sat on the ground and wouldnt move. finally paid them off to let us just do the work, one disapeared for a couple hours then they were all talking alot for the rest of the day.

seems my information about the welder cable is dated.....
let me rephrase that... i am dated, and the information was historically
accurate....

the "core soaking" was something i heard from one of the foremen on the
consumer electronics show, that runs each year in vegas. "heat soaking"
might be a better phrase,,, they just loaded it down to the point where
the transformer core didn't have enough mass for the electrial current
flowing thru it. voltage drops off, and the windings get toasted.... just a
really bad overload of a transformer not properly protected.

the references to drug use date from the early eighties, and predates
crack cocaine. back then, it was called freebase, and you could smell
the either, and hear the torches going inside the bathrooms stalls.

really smart... take something that was just soaked in either, and put it
in a pipe, 4" from your face, and hold a blowtorch to it.... if you survived
that bit of lunacy, there were reports the drug could be addictive....

 

[iwire]

wouldnt that be a code violation? the terminals inside the disco will be supporting the conductors. unless they stick kellums grips on them

Yes, it becomes a choice of 'pick your violation' The NEC correct way is panel mount cam locs mounted on a non-ferris insert to avoid the same issue you pointed out about single conductors.

The right way is a purpose built switch as pictured and I mentioned in a previous post. :smile:

The way I have done it, and often see it done is a 3' to 5' whips supported to the disconnect by a web strap (cargo strap material). No it is not 'listed for the purpose'.

 

[charlietuna]

The movies and TV shows we worked were shot inside commercial office buildings mainly, and we would remove the panel covers and tap directly on the panel lugs with their identified 4/0 whips. We would tie the cables with rope to support them and secure the electric room. The stage hands would take it from there. Some had tap boxes with overcurrent protection and some boxes didn't ! If they were shooting outside the building we would sometimes need permits which were classified as "carnival permit"= $125. .
There was usually one guy who knew what he was doing--"electrically" and the others were "grips" ! The Director is the boss and only knows he needs "this" or "that"-- and they get it for him NOW! So when he starts calling for more light they just start adding it--and they do get into trouble from time to time! And don't get in there way when they are finished--everyone's time stops at that point--and they will run you over to get out of the building. They pay real good--- anything past 12 hours was "Triple time and a half" ---never heard of that, but we had a commercial from Italy run 20 hours---- we worked these movie sets and show sets for twenty years and i never saw of heard of any drugs or booze on them -- there is so much money being spent it is strickly business! And these local stage equipment providers know they can be replaced overnight from Hollywood.............

 

[mxslick]

Yes, it becomes a choice of 'pick your violation' The NEC correct way is panel mount cam locs mounted on a non-ferris insert to avoid the same issue you pointed out about single conductors.

The right way is a purpose built switch as pictured and I mentioned in a previous post. :smile:

The way I have done it, and often see it done is a 3' to 5' whips supported to the disconnect by a web strap (cargo strap material). No it is not 'listed for the purpose'.

Oh, the horror..iwire installs a violation!

In the grand scheme of things though, it is a far safer alternative to hot-lugging and the old alligator clips on the lugs trick.

I agree with those who have mentioned installing a separate "lug can" as yes, the roadies WILL strip out any screws/lugs in a short time, so make those easily replaceable.


When working as a sound roadie tech in Nor Cal, we once had a dunce who tried to "help out" at show end by disconnecting the cam locs on our feeder..starting with the ground! I bellowed at him as he was about to pull the neutral (the other three phases were in and hot) with our dimmer rack (like the one in the op's pic) AND our stage monitor amp rack powered up!!

The boss had me write up laminated tags with the proper connect/disconnect procedures attached to both ends of our feeders and on our whips. I was also designated to train one other person in proper procedure and only he and I were allowed to touch the feeders.

And then there was the know-it-all from a famous performer's band who knew everything, and thought that he could ground their lighting genny by throwing the end of the cable in the lake behind the showroom..and then ran his lighting computer on shore power. :roll: Some very expensive gear got fried by the 180v difference between shore ground and light rig ground.

 

[pbeasley]

When working as a sound roadie tech in Nor Cal, we once had a dunce who tried to "help out" at show end by disconnecting the cam locs on our feeder..starting with the ground! I bellowed at him as he was about to pull the neutral (the other three phases were in and hot) with our dimmer rack (like the one in the op's pic) AND our stage monitor amp rack powered up!!

The boss had me write up laminated tags with the proper connect/disconnect procedures attached to both ends of our feeders and on our whips. I was also designated to train one other person in proper procedure and only he and I were allowed to touch the feeders.

Examples like this spawned the whole Posi-lok craze. That lasted for 5-6 years and then someone finally figured out you could just change the requirements on the connector listing and add a competent person clause, along with make/break order directions on listed equipment with these installed. It was enough to keep the lawyers happy anyways.

R.I.P. Posi-lok.

 

[wireguru]

Examples like this spawned the whole Posi-lok craze. That lasted for 5-6 years and then someone finally figured out you could just change the requirements on the connector listing and add a competent person clause, along with make/break order directions on listed equipment with these installed. It was enough to keep the lawyers happy anyways.

R.I.P. Posi-lok.

and thank GOD they figured that out, I like what I pay for cams, i would hate to thave to pay 5x that for posi lock type devices.