The Angle of the Dangle

Dear Swami,
 
I’m working on a show where some electricians use their slip-joing pliers (AKA, Channellocks) to twist cam-lok connectors on my feeder cable. They all think the plastic insulators have to be 180 degrees offset when the connectors are mated. I’ve combed through the cam website, but the best I can find so far is that there are no tools needed to install. Are there any resources describing the proper mating angle?
 
Signed,
Twisted in Toledo
 
Dear Twisted,
 
What we in the entertainment industry generically call camlocks (or cam-loks) are single-pole locking connectors. Cam-Lok is the Cooper Industries brand name, which includes a range of different types. The type we commonly use in entertainment is the J-Series E-Z1016, which can accept 2/0 or 4/0 cable, and it’s rated for up to 600V and 400 amps of continuous duty. If you look at the specs for that connector, it says that it provides up to 600 pounds per square inch of contact pressure with 1/3 of a turn, which is 120°. If you make a complete ½-turn (180°), my guess it would be about 0 pounds per square inch because it would probably break. But there are a couple of different brands, some of which lock at 120° while others lock at 180°, which is why some people believe all cam-loks should be locked at 180°. Be mindful of which you have and be careful not to over-torque them. 

There are cam wrenches available that are designed to make it easier to connect and disconnect cam-lok connectors. They come in handy when the terminals are close together and there's not much room for your fingers, and when the connections are tight.
 
Incidentally, cams are not my favorite type of single-pole locking connector. Powerlocks are more commonly used in Europe and they are safer than camlocks because they an IP rating of 25, which provides finger protection against shocks. They have a plastic cam that closes over the contacts when they are not mated, so you can’t stick your finger (or tongue) on it whether or not it’s mated.
 
Signed,
Swami Candela of the Third Millennium

Comments

Post a Comment

Popular posts from this blog

Which direction do you coil cable?

Image
Dear Swami, I'm working on a show with some electricians who insist that feeder cable should be coiled in a clockwise direction, but I think it depends on the cable. What's the proper direction to coil cable? Signed, Coiling in Columbia Dear Coiling, Does the sun rise to your right or to your left? Like the direction of the sun, the direction to coil cable depends on which way you are looking at it. To get it right every time, follow the natural coil of the cable. If it wants to coil clockwise, coil it clockwise. If it wants to coil counter-clockwise but you want to coil it clockwise, then flip it over and coil it clockwise. Either way, the sun will shine upon you. Signed Swami Candela of the Third Millennium
Read more

Amps Are All Askew

Dear Swami, I'm stumped (and so is everyone I've asked thus far). I can't seem to figure out the power draw on a show. Here's the layout: 15 - VL4k spots @ 208V; 16,000W each = 24,000W 3 - Clay Paky Alpha 800 @ 208V;  1200VA each =  3600W (assuming PF = 1) 12 - S4 Series 2 Lustr @ 208V; 168W each =  2016W 3 - Colorado Solo1 @ 208V; 62W each =  186W So that's: 24,000   3,600   2,016      186 29,802W total   The incoming voltage from the service is about 117V phase-to-neutral and about 202V phase-to-phase. When I do the math (29,802W ÷ 202V), I keep coming up with 147.5A total, or 49 amps per leg in a balanced 3-phase system. What my meter is telling me is about 82 to 86 amps with every light in the rig on full. Unfortunately, audio and video are using the same service, so that pushes it up to the low 90s range, and it's a 100-amp service, so it is way too close. Am I missing so...
Read more

Segregating DMX

Image
Dear Swami, I've heard people say that you should separate fixture types on their own DMX line or they will not work properly. Is that true? Signed, Lines Crossed in Dimmer Land Dear Crossed, The sky is dotted with clouds that color truth. DMX is well defined and as long as the maker of the machine follows the path of the protocol it will take flight. There is no technical reason for segregating DMX fixtures by type, although there may be historical reasons. In the early days of automated lighting, Martin used an non-compliant pinout and swapped pins 2 and 3. If you used an adaptor it would work with any other DMX devices. Old habits are like the weeds that grow between the cracks in the sidewalk. To be rid of them is hard. There may be other reasons for the practice of segregating DMX by fixture type but it has nothing to do with compliant fixtures.
Read more