Old Twistlock Connectors

[soundguy99]

Hi Guys,
We have an old theater with allot of old twistlock connectors.
As I have been going through our connectors and adapters I have noticed allot of them are in bad shape.
I want to look at getting new connectors to replace them but having a bit of a hard time trying to find replacements.
The connectors are similar to the ones found at this link.
http://oakbluffclassifieds.com/Heavy-Industrial/27-hubbell-other-twist-lock-cord-plugs-3-4-pole.aspx
There all 3 pin with the ground black turned out (Not in).
Some I found are Rodell 250V 20 amp, and some are I believe are hubbel and have 120V 20 amp on them.
I have also been told they look like an eagle connector.
I ultimately need 120V 20 amp but they also need to mate with these connectors as all of our electrics have the pannelmount version of these.
I got one of our electrical companies to bring in what I thought was the connector only to find out that the physical size of the plug was a much smaller plug.
Just wondering if anyone knew about these connectors and weather or not you can still get connectors that mate with these and what the exact model is, or is it a situation that they are just obsolete.
Any help would be greatly appreciated,
Thanks,
soundguy

 

[RickR]

I've run into a few sites with non-NEMA twist locks. Hubbell http://www.hubbell-wiring.com/catalog.aspx had some that seemed to fit.

An important note is on all the data sheets and packages, "for replacement use only" and they are not UL! So make your system work, but notify the higher ups that these are on the safety borderline.

 

[STEVETERRY]

I've run into a few sites with non-NEMA twist locks. Hubbell http://www.hubbell-wiring.com/catalog.aspx had some that seemed to fit.

View attachment 11636 View attachment 11637

An important note is on all the data sheets and packages, "for replacement use only" and they are not UL! So make your system work, but notify the higher ups that these are on the safety borderline.

When introduced, these connectors had a dual rating: 250V 20A and 125V 20A. This meant that in a 250V application, an ungrounded (phase) conductor was present on both current-carrying contacts. In a 125V application, a grounded neutral conductor was present on one of those contacts. This is where UL put their foot down almost 40 years ago. They said, "If the contact is white or silver, it must have a neutral." In addition, this connector created a condition where one could not be absolutely certain of the voltage present at a receptacle without measuring it.

There is nothing inherently unsafe about these connectors. They are "non-UL" and "non-NEMA" for the reason above. As long as all the connectors in a facility are wired the same way (125V grounded neutral in the case of the OP), they meet the NEC for the year they were installed, so there is no code or safety issue. However, if many connectors in the facility are in bad shape, the OP should consider replacing them all in one fell swoop with a modern NEMA or ANSI E1.24 connector. The primary reason for this is that the nub-out locking connectors are getting increasingly hard to find and very expensive.

ST

 

[Scenemaster60]

There were thousands of facilities that installed these connectors in the late 1960s and early 1970s. My junior high had them (1969 system), Inver Hills Community College had them (1970-ish, replaced with stage pin in 2009), O'Shaughnesy Auditorium at the College of St. Catherine in St. Paul (1970) still has this connector on over 90% of its inventory. I don't what year exactly UL put their foot down about these connectors but by 1975 or so every facility that I have ever encountered either had NEMA (ground-in) twist locks or had stage pin.

The biggest issue with this connector from my perspective is determining polarity of the plugs and receptacles. The current carrying blades were simply labeled "x" & "y". Well that's helpful! Which is the hot and which is the neutral? If you're lucky, the electricians decided that "x" would be hot and "y" would be the neutral and were consistent with this for the entire facility. I have heard of facilities where this polarity was reversed several times within the same plugging box!

The only way to know for certain was to check each receptacle with a test lamp or meter. For incandescent loads this presented no operational hazard, per se. If you start connecting LED or moving fixtures to these circuits (via non-dims on an ancient patch panel or using relay or constant circuit modules on DPC retro-fit) you better know the polarity of EVERY receptacle before you proceed or you will have some expensive damage on your hands!

 

[Jay Ashworth]

Here's a (relatively) complete chart of NEMA twist-locks:

http://www.stayonline.com/reference-nema-locking.aspx

For the record: count me amongst the people who think this is an excellent time to bite the bullet -- if it's at all possible, and I know sometimes it's not -- to do a retrofit with NEMA compliant connectors. Your insurance company will probably love you for it.

 

[Scenemaster60]

And here's the non-NEMA chart:

http://www.stayonline.com/reference-non-nema.aspx

The one you need is the fourth one down:

http://www.stayonline.com/detail.aspx?id=14071
&
http://www.stayonline.com/detail.aspx?id=14057

Here's an older Hubbel male connector from my stash:

 

[venuetech]

The only way to know for certain was to check each receptacle with a test lamp or meter.

A non-contact voltage tester could be helpful to quickly determinate the hot.

 

[soundguy99]

Thanks allot guys thats a huge help and I will definitely be looking into this,
I understand all you recommendations to replace them with proper nema connectors, and in fact during our last lighting overhaul they did replace all of our FOH plugs with standard Nema twistlocks, however to completely do another, electric overhaul on all of our stage circuits and electric is just something we can`t afford at this time, especially considering we just finished getting our roof re-done, as well as replaced all of our pull lines and locks for all of our line sets, on top of all of the other mechanical break downs were having to deal with.
Like I said its an old building, that we`re trying to get caught up with.
My other thought is that in a few years time after we get some of the other building issues out of the way and its again that time to deal with the stage lighting again, and make the move to LED fixtures, Thats would be the time to re-do all of the electrical including the stage plugs and electrics, (including non nema connectors) to accommodate the new LED Fixtures as we won`t need as much power or circuits. We would like to change those non nema connectors on our next stage capital project providing our timeline holds.
In the meantime however I would like to slowly replace some of the connectors on some of the cables and adapters we do have.
I appreciate all the help and I hope I will be able order them through our local electrical suppliers.
Thanks again,
soundguy

 

[JD]

With the cost of twist-locks being what it is, changing everything out to stage-pin may be a viable option. For the most part, the old 2P&G still works best.

 

[RickR]

I appreciate all the help and I hope I will be able order them through our local electrical suppliers.

Hubbell is a giant corp. and should be available to everyone.

One other tip: take one of your old plugs into the store. There are enough variations that you need to confirm what you want.