50 Amp 125/250-Volt California Standard Connector

[infinity]

Does anyone know why this is called a California standard connector? The NEMA number is CS6364 which is different than the typical L14-30P or L15-50P number.

 

[texie]

I always heard that it started with the film industry and the thinking was that they were a better design. Don't know if this is fact though.

 

[sw_ross]

I was asking the same question to my supply house just yesterday!
They weren’t able to give me an answer.

 

[infinity]

Someone at work asked me what the configuration was for a 50 generator inlet and I assumed that it was an L14-50. I was surprised to see the Cali standard.

 

[drcampbell]

I've also heard it called the "Taco Truck" standard.
One of the nicest things about standards is that there are so many different ones to choose from.

 

[b1miller]

Pretty much the standard connector for spider boxes and cabling.

 

[Coppersmith]

I always heard that it started with the film industry

I heard that same thing.

 

[LarryFine]

To see what the discussion is about:

 

[GoldDigger]

My understanding was that the California connectors were introduced because there simply was no NEMA equivalent.

The L15-50 is designated as 250V three phase with ground and no neutral. You could use on of the hots as a neutral to get 4 wire 120/240, but it would be really bad to interchange same plug wired for two different purposes!

Speculation on CA origin is film industry needs, or big RVs as original demand.
Currently a good size for a large portable generator.

 

[zbang]

Best I've been able to find-

"I believe the California plug gets its name from being developed as a safer connector for the early days of the Hollywood Film Studios. The first hi-ampereage connectors used in the studios were paddle plugs used in theatres, which were ungrounded. The California plug was grounded by the outer steel shroud, which also protected the male contact pins from damage when the cables are dragged around the set every day. The grounded shroud helps absorb the Arc-Flash if the connector is plugged or unplugged while energized. The paddle plug was notoriously dangerous for Arc-Flashes, especially in the older DC powered Theatres in the first years of electric lighting for the stage! "

Make of that what you will. I will say that the "paddle" or "stage" plugs (not the new pin connectors), were not engineered for safety at all.

 

[Todd0x1]

CS6364 is not a nema designation, its a part number that everyone else copied.

The 50 amp locking nema is SS2-50. This connector is NOT compatible with the CS. It is common in marine and RV applications and does not have the center alignment pin..

The connector does not have its origins in the film industry, in the early days they used paddles, pins, and lugs. More recently camlock and bates. 50A CS is used in limited amounts in film usually in base camps for trailers and small distribution.

The CS connectors came from construction. Early on there were two different formats. The California Standard had the alignment pin, and there is a very similar one with no alignment pin. CS was used on the west coat, and on the east coast the other one was used. CS eventually won out.

 

[zbang]

The 50 amp locking nema is SS2-50. This connector is NOT compatible with the CS. It is common in marine and RV applications and does not have the center alignment pin..

AFAICT, without the pin (on the line side) they're quite compatible. We get a fair number of food trucks that have the no-pin varient; just pull the pin and plug them in (save/reinsert the pin when done).

The CS connectors came from construction. Early on there were two different formats. The California Standard had the alignment pin, and there is a very similar one with no alignment pin. CS was used on the west coat, and on the east coast the other one was used. CS eventually won out.

Could be.... have some references to that? I haven't found any. Why "California standard" (which was the original questions), and why two variations (different manufacturers?).

 

[Todd0x1]

AFAICT, without the pin (on the line side) they're quite compatible. We get a fair number of food trucks that have the no-pin varient; just pull the pin and plug them in (save/reinsert the pin when done).



Could be.... have some references to that? I haven't found any. Why "California standard" (which was the original questions), and why two variations (different manufacturers?).

I don't have any references offhand. It is my understanding (as I recall from conversations years ago) that some manufacturer out here started making what we know as CS and they were used in construction power during the post war boom. All the big electric manufacturers were on the east coast along with NEMA and theirs were different.

 

[brantmacga]

I read something once that said because there wasn’t a NEMA equivalent plug, what we now know as the CS plug is what was approved by California regulators.

One of the restaurant brands we build for has started using CS plugs in place of 15-50R/P on their fryers and grills. A common service call for me over the last several years has been replacing the 15-50 components when they don’t get fully inserted after sliding the appliance out for cleaning.


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[Todd0x1]

I read something once that said because there wasn’t a NEMA equivalent plug, what we now know as the CS plug is what was approved by California regulators.

One of the restaurant brands we build for has started using CS plugs in place of 15-50R/P on their fryers and grills. A common service call for me over the last several years has been replacing the 15-50 components when they don’t get fully inserted after sliding the appliance out for cleaning.


Sent from my iPhone using Tapatalk

Very expensive but that seems like a good application for Meltric connectors.

 

[Todd0x1]

AFAICT, without the pin (on the line side) they're quite compatible. We get a fair number of food trucks that have the no-pin varient; just pull the pin and plug them in (save/reinsert the pin when done).

You are correct. I for some reason was thinking the pin positions and keying were different. I have two different males here an RV SS2-50 inlet and a 63CR65 from cooper and both of those seem to line up with a CS female (which I am not tearing the pin out of to make sure)

I wonder if it is something stupid like the pin was added as a workaround on a hubbell twistlock patent?

 

[zbang]

I wonder if it is something stupid like the pin was added as a workaround on a hubbell twistlock patent?

Could be. Or just something to make it different. Without knowing when they appeared on the scene, it's all guesswork (not that I see this as a problem ).

BTW, the pins on most of them are just knurled and press-fit, with pliers and some effort they pull out.

 

[Jraef]

I always heard that it started with the film industry and the thinking was that they were a better design. Don't know if this is fact though.

Yes, that's it. In the early days of the film industry, the filming was always done outdoors to have enough light, which is why it ended up in Hollywood (the precursor to Hollywood was a little town in the Bay Area called Niles, which is where most of the early Charlie Chaplain films were made. But fog became problematic for filming schedules). Even the notorious sunny skies of SoCal were not enough though, so they started filming indoors where they needed very bright lights (Klieg Lights) that required a lot of power. NEMA twist lock did not yet exist, and the standard paddle plugs used for stage lighting had problems with arcing. Film is VERY flammable, so arcing was a potential disaster. So the film industry developed their own version of plugs and receptacles that had early forms of arc resistance and a twist locking feature so that they wouldn't come undone when being dragged around. When Hubbel later used that concept to create the Twist-Lock that was eventually adopted as a NEMA standard, the California Plugs were already in use for decades, so they were not going to change.* It's still used a lot in all of the entertainment industries because the special gensets for the film industry get rented out by other industries as well and have those on them.

I had a customer decades ago that made the special gensets for the film industry (they are VERY VERY quiet) and had to use those connectors, so I had to know why.

*The so called "California Plug" predates Hubbel Twist-Lock by 30+ years. It was not called a "California Plug" until Hubbel tried to get everyone to change and failed, so to distinguish it from their version, they came up with that moniker. It has nothing to do with regulations or special rules in California, contrary to what people want to think.

 

[Todd0x1]

According to Hubbell the twist lock was invented and brought to market by them in 1929, I think this is the twistlock product and not necessarily a 50 amp version.

Can someone show evidence of the film industry using the 125/250v CS twistlocks in the early years? I really feel like that is inaccurate. Mole Richardson dates back to the 1920s and they never had any CS twistlock stuff until recent addition to portable distros to power basecamp trailers. I'm going to reach out to someone I know in Local 728 and see if the union has any info on this.

I've been working with film gensets for going on 25 years and even late into the 1990s (when the film gensets even still had DC output busses available) they didn't have 50 amp CS connectors on them. Those started appearing maybe 10 or 15 years ago when the connector started getting used to power base camp and trailers. Construction gensets have always had 50 amp CS connectors on them to connect spider boxes.

Even today, film and television has little use for the split phase power on a 125/250v 50A CS twistlock. Set lighting uses Camlock for feeders, 100A (and some 60A) bates to larger fixtures and to lunchboxes to break out 20A Edison (straight blade NEMA 5-20R (with everyone using 5-15 on cords and equipment). Except in base camp. There you see lots of 50A cable going to trailers, and to lunchboxes for 20a circuits. There they need the split phase power due to some trailers having a 4 wire connection via 14-50 or 50A CS. They also use adapters that have a 50A male plug and two TT-30R pigtails. to power trailers using TT-30 plugs.

All that big film lighting is all single phase 2 wire. Either 120v or 240v. From carbon arc, to tungsten, to HMI, to LED, 1K to 20K, it was all 120v 20A, 120v 30A, 120v 60A, 120v 100A or 240v 100A. There was no place for a 50 amp 4 wire circuit.

 

[zbang]

FWIW, I looked in my copy of the Set Lighting Technician's Handbook (Harry C. Box, 1993) and about the only mention of twist locks at all is basically for utilization equipment, nothing for distribution. I think we can agree that the CS style was common in the 1970s and probably in the 1960s but it would be nice to see some references (they're in my 1979 Graybar catalog, looking for something older).

Continuing the quest....