Cam-Lok Connections

LPdan

Well-Known Member
Hello,
We are planning to have a 400A Cam Lock panel installed in our theater, and I have a question about reversed polarity neutral and ground connectors. The panel manufacturer said most people do not reverse these connectors, and it is perfectly safe.
Can anyone comment on whether these should be reversed for theatrical application?
Thanks in advance!
 

DaveySimps

CBMod
CB Mods
Premium Member
Reverse "polarity" is not necessarily a great way to say it. Reversed ground and neutral really just refers to the reversing of the gender or type of connector at those conductors. Many people do this to help prevent accidentally tieing in a hot phase into a ground or neutral socket. I have reversed G&N here in my venue, but I stock green and white CAM turn arounds for those who may come in with out that configuration.

~Dave
 

RonHebbard

Well-Known Member
Premium Member
Hello,
We are planning to have a 400A Cam Lock panel installed in our theater, and I have a question about reversed polarity neutral and ground connectors. The panel manufacturer said most people do not reverse these connectors, and it is perfectly safe.
Can anyone comment on whether these should be reversed for theatrical application?
Thanks in advance!
If this was in my home venue, I'd have two neutrals and one ground source on male connectors, keep back to back female gender benders available nearby SECURELY LOCKED UP to prevent from escaping with the next tour passing through. This worked well for us with 3 phase / 5 wire / dual redundant neutral four ought in 1973.
Toodleoo!
Ron Hebbard
 

egilson1

Senior Team
Senior Team
CB Mods
Premium Member
I can tell you that in low light situations, Green and Blue can look very similar. Having reverse N&G is helpful to prevent that. IF you decide to go that route, I'd suggest getting a set of CAM turn arounds so that you can accommodate non-reverse N&G systems.
 

danTt

Well-Known Member
I would say it's equally dependant on what gear you reguarally expect to connect. If your portable distros are all one way or the other, get a panel that matches.
 

SteveB

Well-Known Member
The theatrical consultant in our new building had installed Lex PowerGate company switches in assorted 200 and 400 amp sizes, all have the nuetral and ground CamLok connectors reversed. That's a common feeder configuration in the NYC region.
 

derekleffew

Resident Curmudgeon
Senior Team
Premium Member
And here I thought we had solved this issue ten-some years ago... https://www.controlbooth.com/threads/cam-turn-arounds.18977/
When I worked for a major rental company in the US, I had trouble with this particular standardization issue across branches, let alone companies. I don't think it is likely that one sex of neutral or ground will be standardized, as there is large cost to change, and little safety or interoperability benefit. That's why there are E1016 turnarounds!

In the more than one needs to know category (from same thread as above)...
Some history:

1. Cam-Lok E1016 connectors were first used in an entertainment application on Colortran 6 x 6kW portable dimmer packs, circa 1977. In order to attempt UL Listing, they needed non-intermateablility of hot, neutral and ground. This was at least 7 years prior to NEC recognition of single conductor feeders and single-pole separable connectors, with their associated connection-order rules. Without these NEC rules, UL made up some of their own: no intermateability of hot, neutral, ground. (Note that even today, the NEC makes no statement about non-intermateability of these specialized connectors).

2. Colortran used Empire Products E1016 males on the hots, an E1016 female on the neutral, and a female Palmgren Screw-Lok on the ground. The Palmgren Screw-Lok was a hideously expensive, long lead-time connector that used the same female neoprene housing as an E1016, but was not mateable with E1016. Another great feature: its cable boots only came in a vulcanized version, not the "Lektra-Link" style that is now standard on E1016. That meant:

--A vulcanizing press
--Vulcanizing tape
--Gooey vulcanizing lube
--At least 10 minutes curing time per connector
--No field installation or removal, unless you had a vulcanizing press in your workbox

Palmgren Screw-Lok connnectors
www.integro-usa.com

3. Production Arts owned a bunch of those Colortran packs, and after extreme frustration with the Palmgren Screw-Lok's, we changed them out for female E1016's. Our logic: better to guarantee no intermate of hots with neutral and ground. That arrangement became our standard on touring gear, and I guess our logic caught on with some other rental companies-- but there were notable holdouts such as Vanco.

ST

In the end it really doesn't matter, until one doesn't have the appropriate turn-arounds. Of course, then it matters A LOT! Only once have I seen a venue whose company switch had both male and female of both ground and neutral. I liked that muchly, but it did make for a non-standard (dbl-height, IIRC) panel.
 

derekleffew

Resident Curmudgeon
Senior Team
Premium Member
I would say it's equally dependant on what gear you reguarally expect to connect. If your portable distros are all one way or the other, get a panel that matches.
Most distros are configured for pass-thru, and thus already have both sexes. It's perfectly fine to connect a company switch to a distro's "output" G&N connectors--"in" and "out" are connected together immediately inside the distro anyway.
 

danTt

Well-Known Member
Most distros are configured for pass-thru, and thus already have both sexes. It's perfectly fine to connect a company switch to a distro's "output" G&N connectors--"in" and "out" are connected together immediately inside the distro anyway.
Sure, but much more of a pain to plug in the bottom row after the top row, which starts happening when you get "creative" like that.

Or worse, when you get one of the rare prg 96racks with dual inputs instead of an in and a thru.
 

Dover

Active Member
I agree with your point that they shouldn't be made up in the dark but disagree that it serves to eliminates any rationale. "Don't stick your arm in the wood chipper" shouldn't even be something that needs to be said much less put on a warning sticker but every power feed tree chipper made not only has the stickers but has an emergency bar to reverse the feed rollers if you get sucked in. If just saying "don't do stupid things" was enough, a lot of safety problems would be solved.
Not all cam cables have colored ends, it is common in the generator and industrial temp power sectors where multiple parallel cam feeders are used to use all black connectors. Ironically that is also the industry most likely to use straight N&G. Reversed N&G prevents, barring gender changers, the cross connection of the hots to the colds no matter what color or lack of color the wires or connectors are. It serves as one final safe guard, you could still swap the Neutral and Ground but you will always have a ground path. I have been on the investigation team when an electrical crew closed a 1200a breaker into a dead short. Fortunately no one was seriously injured because the switch board contained the blast but the resulting arc flash and fire still melted a good chunk off the top of the section bus bars. If the gear had failed it likely would have been a death investigation not property damage.
 

STEVETERRY

Well-Known Member
And here I thought we had solved this issue ten-some years ago... https://www.controlbooth.com/threads/cam-turn-arounds.18977/


In the more than one needs to know category (from same thread as above)...


In the end it really doesn't matter, until one doesn't have the appropriate turn-arounds. Of course, then it matters A LOT! Only once have I seen a venue whose company switch had both male and female of both ground and neutral. I liked that muchly, but it did make for a non-standard (dbl-height, IIRC) panel.
I couldn't have said it better myself. Oh wait...I did! :)
 

STEVETERRY

Well-Known Member
And here I thought we had solved this issue ten-some years ago... https://www.controlbooth.com/threads/cam-turn-arounds.18977/


In the more than one needs to know category (from same thread as above)...


In the end it really doesn't matter, until one doesn't have the appropriate turn-arounds. Of course, then it matters A LOT! Only once have I seen a venue whose company switch had both male and female of both ground and neutral. I liked that muchly, but it did make for a non-standard (dbl-height, IIRC) panel.
BTW, the NEC is silent on the gender of single-pole separable connectors on grounded neutral or equipment grounding conductors. From a Code point of view, either gender is acceptable.
 

derekleffew

Resident Curmudgeon
Senior Team
Premium Member
Thanks so much for all the responses! Based on what I'm reading, I'll plan to reverse the N & G, and have some turn-arounds locked up if needed.
Yep, that sounds like a good plan. I'd still inquire with the mfg. the price of adding G&N in the other sex.

Another thought on this: of course you should have the correct turn-arounds, but I wouldn't be quick to offer them. Any touring electrician (or Competent Person, per the NEC) will carry turnaround s, gender-bender s, tails, and such, either in the feeder box, or in his/her/their personal workbox.

As a House Electrician, my rule was always "Use Road equipment first!"
As a Touring Electrician, it always pained me to have to ask the House for anything. It meant I'd over-looked something and thus wasn't prepared like I should have been.
 

RonaldBeal

Well-Known Member
I have run in to some venue company switches that have both ...2 grounds (one each "direction"), 2 neutrals and the three hot legs.
best of all worlds.
 

TimMc

Well-Known Member
Premium Member
NEC 520 and 525 permit single-pole separable connectors to connect portable switchboards if one of several conditions are met - keyed mating connectors to prevent line/neutral/ground misconnection, physical interlocks that force connection order, all the way down to posted warnings and instructions to the qualified personnel regarding connection/disconnection order.

The reason we see reversed gender neutral and ground (with respect to line gender) is it's the easiest, cheapest way to prevent connection to a Line and create a direct short at 400 amps...

CEE form connectors, up to 100 amps, meet the "normal" Code requirement of having Ground connect first/disconnect last, and all line connections connect/disconnect together.
 

Jay Ashworth

Well-Known Member
NEC 520 and 525 permit single-pole separable connectors to connect portable switchboards if one of several conditions are met - keyed mating connectors to prevent line/neutral/ground misconnection, physical interlocks that force connection order, all the way down to posted warnings and instructions to the qualified personnel regarding connection/disconnection order.
Wait.

Didn't a couple other people, in recent comments, just say that NEC *didn't* care if your N's and G's were the same sex?

That's the only kind of keying at hand, right?
 

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