Just curious on your thoughts on flipping the gender of your ground cam wire in a 5 or 4 wire distro system tail set. I've seen it done to keep people from connecting a hot leg to a ground. I have also seen people flip the neutral as well. In other words the hot legs are female and the ground and neutral are male in the tails.
Cam Lock Ground Orientation
- Thread starter Kip Conner
- Start date
Silas Pradetto
Graduate Student
Re: Cam Lock Ground Orientation
Ground and neutral were commonly flipped on lighting distros and dimmer racks back in the day, because the code had some provision that was satisfied by the switch. These days, I never see any house cam feeds with neutral-ground flipped, and I rarely see distros configured as such.
And I have never, ever seen just the ground flipped.
Never seen a generator with reversed neutral-ground either.
Ground and neutral were commonly flipped on lighting distros and dimmer racks back in the day, because the code had some provision that was satisfied by the switch. These days, I never see any house cam feeds with neutral-ground flipped, and I rarely see distros configured as such.
And I have never, ever seen just the ground flipped.
Never seen a generator with reversed neutral-ground either.
Re: Cam Lock Ground Orientation
Thanks Silas. I had not seen it in a while either… I haven't been in the position where I've had to tie in a distro in several years, but it has come up twice in 2 weeks. The distro I tied in was bare wire but house cams were available to me to I thought I might make a set of tails with cams.
Thanks Silas. I had not seen it in a while either… I haven't been in the position where I've had to tie in a distro in several years, but it has come up twice in 2 weeks. The distro I tied in was bare wire but house cams were available to me to I thought I might make a set of tails with cams.
Re: Cam Lock Ground Orientation
All of our distros have ground and neutral cams reverse-gendered. Tie-ins around here tend to be about 50/50 one or the other, so we'd be carrying turnarounds either way.
But most places nowadays have installed cams, so you should carry turnarounds.
All of our distros have ground and neutral cams reverse-gendered. Tie-ins around here tend to be about 50/50 one or the other, so we'd be carrying turnarounds either way.
But most places nowadays have installed cams, so you should carry turnarounds.
Re: Cam Lock Ground Orientation
My understanding is that people do this to keep other people from tying hots to ground/neutral or vice versa. Which is just fucking unbelievable to me. If that's the sort of problem you have, get into another business ASAP before you start accidentally using tie line to hang loudspeakers or something else unimaginably stupid and dangerous. Screwing up a patch on stage is one thing, but screwing up your cam tie-in is inexcusable.
My understanding is that people do this to keep other people from tying hots to ground/neutral or vice versa. Which is just fucking unbelievable to me. If that's the sort of problem you have, get into another business ASAP before you start accidentally using tie line to hang loudspeakers or something else unimaginably stupid and dangerous. Screwing up a patch on stage is one thing, but screwing up your cam tie-in is inexcusable.
Re: Cam Lock Ground Orientation
The reversed-gender ground/neutral is done to satisfy requirement of the Code. In the 2005 edition (the version my AHJ uses) the requirements are found in 520.27 (conductors) and 520.53, et seq (through 520.62). The reversed connectors are seen as a mechanical interlock.
When working out-of-doors, events must comply with NEC 525 and parts of 530 as well, and the Audio Signal Processing and Amplification comes under 640.
These kinds on discussions always interest me as it tends to reveal both the OP's understanding of both Codes and practices (that's a good thing, really) and how local Authorities Having Jurisdiction interpret the Code (or what the locale has implemented).
The reversed-gender ground/neutral is done to satisfy requirement of the Code. In the 2005 edition (the version my AHJ uses) the requirements are found in 520.27 (conductors) and 520.53, et seq (through 520.62). The reversed connectors are seen as a mechanical interlock.
When working out-of-doors, events must comply with NEC 525 and parts of 530 as well, and the Audio Signal Processing and Amplification comes under 640.
These kinds on discussions always interest me as it tends to reveal both the OP's understanding of both Codes and practices (that's a good thing, really) and how local Authorities Having Jurisdiction interpret the Code (or what the locale has implemented).
Re: Cam Lock Ground Orientation
Learn something new every day! Then I will continue to be grumpy, but only that I feel that part of the code is stupid
Learn something new every day! Then I will continue to be grumpy, but only that I feel that part of the code is stupid
Re: Cam Lock Ground Orientation
Of all the things to screw up on a show, this one would have to be the most retarded.
ALWAYS METER THE CAMS BEFORE YOU CONNECT THEM TO YOUR GEAR! ALWAYS.
This is the one connection that could do the most damage to everything in your system, you should respect it enough to make SURE it is always right.
Yeah, me too.Learn something new every day! Then I will continue to be grumpy, but only that I feel that part of the code is stupid
Of all the things to screw up on a show, this one would have to be the most retarded.
ALWAYS METER THE CAMS BEFORE YOU CONNECT THEM TO YOUR GEAR! ALWAYS.
This is the one connection that could do the most damage to everything in your system, you should respect it enough to make SURE it is always right.
Re: Cam Lock Ground Orientation
For Bennett- if you read the Code, the mechanical interlock (actual ability to connect only the "correct" cable, one at a time) like Posi-Lok is the first and preferred way. Posi-Loks suck. I've seen them on touring feeder a couple of times in 15 years, and that was on the feeder between generators and switch gear. Architects specify them because they're absolutely, positively NEC 520/525 compliant. Every venue that has them ends up building or buying Posi-to-cam tails.
Reversing the grounded conductors makes it impossible to immediately mate a phase leg to neutral or ground, effectively meeting the actual need of the Code.
Finally, posting a warning notice that requires the use of "Authorized Personnel" and specifies the connection and disconnection order will also suffice (unless the local AHJ requires the other measures).
@ Josh - Yepper. I train our employees to meter the tails before connecting the feeder; turn the switch off and verify that the other end of the feeder is connected, and then mate the tails to feeder. Re-verify that the other end of the feeder is properly connected to the appropriate device and that the device's master breaker or all branch circuit breakers are off. Throw the big switch and then meter the voltages at the device. Once determined to be correct, loads may be switched on.
This is one way you find "stinger" or "high" phase legs and other undocumented surprises, or find out your electrician is color blind and that green and red look the same to him...
For Bennett- if you read the Code, the mechanical interlock (actual ability to connect only the "correct" cable, one at a time) like Posi-Lok is the first and preferred way. Posi-Loks suck. I've seen them on touring feeder a couple of times in 15 years, and that was on the feeder between generators and switch gear. Architects specify them because they're absolutely, positively NEC 520/525 compliant. Every venue that has them ends up building or buying Posi-to-cam tails.
Reversing the grounded conductors makes it impossible to immediately mate a phase leg to neutral or ground, effectively meeting the actual need of the Code.
Finally, posting a warning notice that requires the use of "Authorized Personnel" and specifies the connection and disconnection order will also suffice (unless the local AHJ requires the other measures).
@ Josh - Yepper. I train our employees to meter the tails before connecting the feeder; turn the switch off and verify that the other end of the feeder is connected, and then mate the tails to feeder. Re-verify that the other end of the feeder is properly connected to the appropriate device and that the device's master breaker or all branch circuit breakers are off. Throw the big switch and then meter the voltages at the device. Once determined to be correct, loads may be switched on.
This is one way you find "stinger" or "high" phase legs and other undocumented surprises, or find out your electrician is color blind and that green and red look the same to him...
Re: Cam Lock Ground Orientation
This is a legit reason to have a reversed ground on cams.
To be safe, reversing ground and neutral would be best. However, if your cable inventory is used for both single phase and 3 phase operation, flipping neutral doesn't work for 4 conductor cable. We have quite a bit of 4 conductor cable that we use for both. Usually with our 3 phase stuff (big lasers) we don't need a neutral feed, so 4 conductor is fine. However, if we have to have a neutral conductor, we can then run a single, separate ground conductor. The ground conductor in the cable is then clearly taped blue as a hot leg. Yes, I'm sure that violates some code, because inside the wire it's still green, but it's still WAY safer than what most seem to do around these parts.
This is a legit reason to have a reversed ground on cams.
To be safe, reversing ground and neutral would be best. However, if your cable inventory is used for both single phase and 3 phase operation, flipping neutral doesn't work for 4 conductor cable. We have quite a bit of 4 conductor cable that we use for both. Usually with our 3 phase stuff (big lasers) we don't need a neutral feed, so 4 conductor is fine. However, if we have to have a neutral conductor, we can then run a single, separate ground conductor. The ground conductor in the cable is then clearly taped blue as a hot leg. Yes, I'm sure that violates some code, because inside the wire it's still green, but it's still WAY safer than what most seem to do around these parts.
Re: Cam Lock Ground Orientation
While I haven't read the 2005 NEC, I've got older and newer versions handy, and they all have the same wording regarding single-pole separable connectors for theatrical applications [for those playing along, it's 520.53(k), 530.22, and 525.22(d), although articles 525 and 530 may have been rearranged between 1999 and 2008). All have the same wording in the 2011 NEC]. That wording allows for 3 methods of protecting the connectors:
1) An interlock that prevents the connectors from being energized untill all are mated (these are becoming more common on company switches and other tie-in points)
2) Listed sequential-interlocking-type connectors that can only be connected in the proper order (e.g. Posi-Lok)
3) A notice posted by the connectors dictating the proper conenction sequence (by far the most common)
Swapping the gender on the ground and neutral cables doesn't appear to satisfy any of these 3 methods. I will grant that it does make a hot/ground swap less likely, but I'd argue that someone who makes that mistake is not a qualified person to be working with feeder connectors. From an explanatory note to 520.53(k) in the 2011 NEC:
"Single-pole separable connectors are quick-connect feeder splicing and terminating devices, not attachment plugs or receptacles. They are designed to be sized, terminated, and inspected by a qualified person before being energized, and are to be guarded from accidental disconnection before being de-energized."
And Brian, the NEC allows for the use of tape to identify ground and neutral conductors larger than 4AWG, but is silent on line conductors. Every inspector I've run across has been fine with field-applied colored electrical tape designating feeder function (phase, neutral, ground).
While I haven't read the 2005 NEC, I've got older and newer versions handy, and they all have the same wording regarding single-pole separable connectors for theatrical applications [for those playing along, it's 520.53(k), 530.22, and 525.22(d), although articles 525 and 530 may have been rearranged between 1999 and 2008). All have the same wording in the 2011 NEC]. That wording allows for 3 methods of protecting the connectors:
1) An interlock that prevents the connectors from being energized untill all are mated (these are becoming more common on company switches and other tie-in points)
2) Listed sequential-interlocking-type connectors that can only be connected in the proper order (e.g. Posi-Lok)
3) A notice posted by the connectors dictating the proper conenction sequence (by far the most common)
Swapping the gender on the ground and neutral cables doesn't appear to satisfy any of these 3 methods. I will grant that it does make a hot/ground swap less likely, but I'd argue that someone who makes that mistake is not a qualified person to be working with feeder connectors. From an explanatory note to 520.53(k) in the 2011 NEC:
"Single-pole separable connectors are quick-connect feeder splicing and terminating devices, not attachment plugs or receptacles. They are designed to be sized, terminated, and inspected by a qualified person before being energized, and are to be guarded from accidental disconnection before being de-energized."
And Brian, the NEC allows for the use of tape to identify ground and neutral conductors larger than 4AWG, but is silent on line conductors. Every inspector I've run across has been fine with field-applied colored electrical tape designating feeder function (phase, neutral, ground).
Re: Cam Lock Ground Orientation
Most of the companies I work with have the neutral and ground cams reversed. All of the venues I can think of that have cams installed are not reversed. As far as tagging legs with electrical tape, I know of one instance where the inspector require us to tape the entire boot rather than just on the cable.
Most of the companies I work with have the neutral and ground cams reversed. All of the venues I can think of that have cams installed are not reversed. As far as tagging legs with electrical tape, I know of one instance where the inspector require us to tape the entire boot rather than just on the cable.