Twist-Lock connectors in schools

[egilson1]

@STEVETERRY do you know of anything in the NEC that requires the use of twist lock connectors in “educational settings”. I know that’s vague, so let’s limit it to theatres/auditoriums in public’s schools.

I ask because of a comment on a FB thread stating some locals require it by code.
Thanks!

 

[Darin]

I believe that was my comment! I just came here to ask the same thing. I may be working with old information, but I was taught (in the 90's) that L5-20 was standard for educational settings (and every university I have worked has been twist-lock, which has supported that idea). It seems that there are plenty of universities and high schools that are running 2P+G, so my information may be out of date (or just plain incorrect).

Searching electrical codes online is a fool's errand...

 

[RickR]

There has long been a requirement to avoid dimmers on 'Edison' devices. (sorry my code books are elsewhere) My understanding is that was to avoid damaging non-dimmable equipment.

There's also an amperage mismatch with "edison". They are rated at 15A but most newer stage circuits are 20A.

Many have asked me about "edison" plugs coming loose. I'm not aware of a code requirement, but it's a common concern.

I'm sure Steve has more specifics...

 

[Darin]

Right, Edison is never ideal. My memory of learning requirements was that educational theatres required locking connectors?

 

[Van]

I have not run across Twist-lock in schools as a requirement per code on any of the jobs I've worked on in the last 5 years; both new construction and reno work. As a matter of fact it has become much more common in newer theatres for LED fixtures to have PBG whips installed and incandescent to have GSP or L5-20. we will either see these systems have a mix of 5-15r's and L5-20's on the distros or all GSP/All L5-20's and a bunch of Adapters. We keep Lex very happy.

 

[cbrandt]

I think a lot of schools *think* that locking connectors either are required, or assume they very shortly will be. And they request or specify based on that.

Way back in college my technical director went to great expense to swap out all the stage pin to L5-20 on all dimmed circuits for that very reason. The only L5-20 I have in my rental inventory is adapters for those spaces that use it in their dimming systems...

 

[FMEng]

I have not run across Twist-lock in schools as a requirement per code on any of the jobs I've worked on in the last 5 years; both new construction and reno work. As a matter of fact it has become much more common in newer theatres for LED fixtures to have PBG whips installed and incandescent to have GSP or L5-20. we will either see these systems have a mix of 5-15r's and L5-20's on the distros or all GSP/All L5-20's and a bunch of Adapters. We keep Lex very happy.

GSP and PBG? Do we need third or fourth names for the same connectors we've used forever?

 

[TimMc]

GSP and PBG? Do we need third or fourth names for the same connectors we've used forever?

Gear Serviced Poorly? Ground Severed Potentially?

Pinning By Gilson? Peanut Butter and Ground?

/satire

 

[Van]

GSP and PBG? Do we need third or fourth names for the same connectors we've used forever?

You're from Tacoma? Those are the very common terms we've used in the PNW for at least the last 35 years....Call PNTA or Hollywood, or Bandit, and ask them if they know what they are.

 

[derekleffew]

... do you know of anything in the NEC that requires the use of twist lock connectors in “educational settings”. I know that’s vague, so let’s limit it to theatres/auditoriums in public’s schools.

I have a feeling you're not telling us all of the story. Whenever this topic arises, it stems from, or leads to, a debate about whether 2P&G is a/the proper connector for dimmed outlets. The answer is "Yes, of course it is." However, as dimmed circuits are becoming extinct, so is the connector. Moot point, or will be soon. When Union Connector stops making connectors, the equine is deceased, the rotund diva has crooned, it's over.

In Canada, in the 1980s there was a big and fairly successful push to "outlaw" 2P&G, particularly in educational settings. I don't think the bigotry and hatred were ever actually enshrined in the CEC, but today it is rare to see a 2P&G installed in Canada.

 

[MNicolai]

The primary code issue that I'm aware of is that controlled circuits as part of energy conservation or a building automation system must be designated as such. As duplex receptacles with internal relays are becoming more common place due to energy codes, many new construction offices for example will have a requirement of a certain proportion of receptacles that will turn off on a schedule or in response to occupancy/vacancy sensors. These are required to be labelled as controlled so no one plugs a desktop computer or other critical appliance into them and is surprised when those receptacles suddenly switch off and they lose all their work.

 

[STEVETERRY]

@STEVETERRY do you know of anything in the NEC that requires the use of twist lock connectors in “educational settings”. I know that’s vague, so let’s limit it to theatres/auditoriums in public’s schools.

I ask because of a comment on a FB thread stating some locals require it by code.
Thanks!

There is no NEC requirement that dictates the specific type of connector for a given application. The connector must only be Listed and have the correct rating for voltage and current.

However, local codes and practice (sometimes developed by many years of history) may have more prescriptive requirements such as "Locking-type connectors in schools."

ST

 

[STEVETERRY]

The primary code issue that I'm aware of is that controlled circuits as part of energy conservation or a building automation system must be designated as such. As duplex receptacles with internal relays are becoming more common place due to energy codes, many new construction offices for example will have a requirement of a certain proportion of receptacles that will turn off on a schedule or in response to occupancy/vacancy sensors. These are required to be labelled as controlled so no one plugs a desktop computer or other critical appliance into them and is surprised when those receptacles suddenly switch off and they lose all their work.

These are architectural requirements that do not apply for production circuits in theatres covered by article 520.

ST

 

[ship]

I think everyone is forgetting histroy in why stage pin and stage plug. Two different plugs. Stage pin plug I can date back to at least 1910 and have examples of the 10 or 15A version (in storage w/o able to see rating, as with the 30a version.) At that point twist lock plugs were not invented. Even Edison plugs were not invented... (probably) instead was a slightly different version. I have an example, but it's also in storage. Electrical tape was not even invented for reference. Grounding was an option by at least 1910 or 1916, but only an option as with reflectors to the lights.

Stage pin plugs were in use and there is and has never been anything wrong with them more than any other type of plug other than they might fall out of the socket unless it's slot in the pin was inspected for knife based re-spacing need.

Around the mid-70's (in pre-dating me as a tech person), the twist lock plug was invented. Not the UL-Listed L5-20P, but a twistlock - I believe in California came to market. Soon came the twistlock now NEMA L5-20P.
It was modern and especially in the days before the Bates plug, was locking especially for areal connections. Union Connector - the name brand for stage pin plugs came up with a latching/locking system for their plugs to fight this, but it was a lost cause. Unless you had something to lock onto the latch mechanism often became a bent problem in connecting.
So at that point in the 70's and 80's stages and theater's started to became twist lock. At least from what I remember.
The invention of the Bates stage pin plug which could be tie lined together and was a great thing in the industry... News of it before the S-4 Leko came out was all over the place. That plus perhaps going back to on distro's a 3/4"x2" knockout hole takes up a lot less space than a 1.3/8" Dia. hole for each receptacle. This might have born a researgance in stage pin plug usage during the 90's I think.

Where I work... started in early 99', there are specific markings for 208v cable. A purple stripe adjacent to the company label. I started that system. These days, all the hundreds of stage pin cables I made over the years are being converted to Edison these days. And we are building 208v cables, much less True 1 cable builds. Very glad the PowerCon cable builds have gone away - the worst connector... Kind of sorry stage pin is going away. No real reason for that if well maintained.

 

[Van]

I'm guessing a lot of folks here may be aware of this configuration but in case your in an older house and have not seen what I mentioned above, about having multiple types of plugs in the same facility or distro strip... Here's a pic from an Install we just completed. You can see L5-20R, GSP, and PBG, then the DMX port all in a row. Work-lights are on the Twist locks, Incandescents and dimmable loads on the GSP and LED/Non-dim's on the PBG. Personally, I think it a great solution that will save a lot of equipment.
(Oh and that is a camera anomaly there is NOT a curve in the Batten!)

 

[gafftapegreenia]

I'm guessing a lot of folks here may be aware of this configuration but in case your in an older house and have not seen what I mentioned above, about having multiple types of plugs in the same facility or distro strip... Here's a pic from an Install we just completed. You can see L5-20R, GSP, and PBG, then the DMX port all in a row. Work-lights are on the Twist locks, Incandescents and dimmable loads on the GSP and LED/Non-dim's on the PBG. Personally, I think it a great solution that will save a lot of equipment.
(Oh and that is a camera anomaly there is NOT a curve in the Batten!)

View attachment 24493

My college’s theatre, built 1974, has twist locks for the work lights on the Electro Controls raceways. Always figured I had Jay O. Glerum to thank for that.

 

[danTt]

I'm guessing a lot of folks here may be aware of this configuration but in case your in an older house and have not seen what I mentioned above, about having multiple types of plugs in the same facility or distro strip... Here's a pic from an Install we just completed. You can see L5-20R, GSP, and PBG, then the DMX port all in a row. Work-lights are on the Twist locks, Incandescents and dimmable loads on the GSP and LED/Non-dim's on the PBG. Personally, I think it a great solution that will save a lot of equipment.
(Oh and that is a camera anomaly there is NOT a curve in the Batten!)

View attachment 24493

I'd hate working in a space like this. Why do I need three times the cable inventory to power 120v units? What if I want my par to be a worklight one day and then dimmed as part of the show the next? Why am I still renting a distro and pulling mult when I need 208v, and why am I running really long cables for circuits that are the right flavor for my needs? I get wanting to save people from themselves, and I'm sure I'm not the target audience for this space, but we all know what idiot-proofing does...

 

[techieman33]

I'd hate working in a space like this. Why do I need three times the cable inventory to power 120v units? What if I want my par to be a worklight one day and then dimmed as part of the show the next? Why am I still renting a distro and pulling mult when I need 208v, and why am I running really long cables for circuits that are the right flavor for my needs? I get wanting to save people from themselves, and I'm sure I'm not the target audience for this space, but we all know what idiot-proofing does...

I think it depends on the environment. I could see something like this in a school just to help keep things from getting confused. If it was a professional space I wouldn't want raceways at all, they're way to restrictive.

 

[jtweigandt]

As we have added more and more LED, and have multiple people with multiple skill levels working in the facility, I am glad that we went with a bunch of twist locks now on our FOH to power the Lustrs and the Phoenixes. I still have a "dedicated" stage pin box that is marked with spike tape in red that has our actual "relay" power for other LED stuff over the stage. But we're still using stage pin to edison converters for that. Makes me nervous that someone will swap one of them to a dimmed power plug. Probably will convert those in our future. If the stage pin to edison conversion cable isn't there, the temptation is removed.

 

[JonCarter]

RE: Twislock connectors. Ship, I beg to differ with you. I worked at an outdoor plant in the mid-'50s which had a major electrical upgrade in 1953. All 100 or so of our stage circuits had Hubbell TwistLock receptacles. Stage lighting circuits (crom the cross-connect) were 2p 20A with weatherproof box covers painted silver, constants (work lights, etc.,) had covers painted yellow and microphones (3P 15A) and speakers (3P 20A) had covers painted green. So TwistLocks were in use at least in the early '50s and possibly before.