Moderators, if you could move this to the electrical nostalgia section...Thanks.

I was rummaging through some old devices that I had lying around the other day and came across this older Hubbell Twistlock Receptacle. I've seen many of these installed in older buildings, and I'm assuming that this one predates the nema standard for locking devices. A modern NEMA L5-15 R has a little hook in on the ground slot so this one looked a little odd to me. It carries a dual voltage rating as well. (these are a little before my time)


I got also a bunch of these single Hubbell (and some A-H)receptacles that have a really odd mount. They were in a box of really old electrical stuff at a garage sale. At first you would think that this could fit a raised cover with an opening for a single receptacle, however, the mounting tabs are about a 1/4" too small. I have no idea what these could have been used for, maybe some older plugmold type strip or something. (I have an "adjustment yoke" for a blank cover lying next to it for a gauge)

If you were to take a locking type photocell & compare the configuration of it and the one in the top picture, they are the same, & the receptacle in 2nd pic. is a floorbox receptacle.

I have a box of those Twist loc rec. It is a non grounding type. They were common used during the late 1950 & 60's on fire apparatus. Used on fans & lights. They made a 2 conductor also. They were frequently miss wired as the screws on the early models were not identified. I was in a fire dept that used these. Several of the lights were mis-wired. When you started the generator on the pumper and stretched the cord to a light set on the (wet) ground, if you touched the truck, you got a tingle. One pole was grounded in the generator and the other on the light. Replaced them all with grounded and properly wired TL.

"Old style" (non-grounding) twist lock devices are still available from most manufacturers.

Re the first picture—up to the early 1970s in northern California, these were used extensively on construction sites. At temporary power poles, typically there were a pair of these, one receptacle was labeled “110” and the other was labeled “220”. That way extension cords could be used for either voltage. (Never mind the hazards.)

This was at a time when CALOSHA was just comin’ up to steam, and inspectors were busy with site inspections and issuning citations.

Good stuff,
Junk collector.
I fail to see however, how this is junk.

One thing I love about the older sockets and the like is the small designs used to adorn something like a receptacle.
Like the front face of the recept in your second picture, someone designed that, who I have no idea, but at the time that would have looked good.

To most people that is somewhere where you put your plug in to get something to work.

It's a shame that only electricians appreciate the work that went into these devices.

Here's an old outlet in my mom's place. Turns out Australian plugs will fit, and as this one is fed by 240VAC, the Australian plug would feel nearly at home. Except for the 60Hz, and that both current carrying pins (that's the slanted ones, the vertical one is the ground) are hot with 120VAC. In Australia, one is a neutral, and the hot is 240V 50Hz.

That is a neat receptacle, Wa2ise. I've seen a few of those, but they were wired for 120. A hardware store near me still has the single version of that style, and the NEMA 10-20. I think they have plugs for each variety, too. I actually have an adaptor with that crowfoot pattern, so that you can plug the crowfoot into a standard receptacle.

Good stuff...

Back in my elementary school, we had crowsfoot for 110DC and regular for AC (or was it the other way around? Too long ago :-)
/mike

All our 120V stuff at Ford was fitted with a weird twist-lock pin-and-sleeve plug that fitted into matching weird receptacles.
I know that whacking off the plug of a new tool to install an oddball plug sounded dumb, but we stopped 'losing' electric drills and other small power hand tools almost immediately after the policy was adopted.

The crowfoot plug has been around since at least 1916, as shown in this patent diagrams http://www.videokarma.org/attachment.php?attachmentid=165339&d=1256685729
Another odd outlet: 120VAC 20A

Is there a standard polarity when these sockets are used on 120V?
I'm doing some research for an article on my website with regards to the history of the Australian plug and socket and this is one of my unanswered questions.
As I've explained here previously, this socket design was adopted officially by Australia in 1937, from the U.S, so it is no coincidence Australian plugs fit in the surviving U.S examples.
In Australia the two angled pins could be connected with live and neutral either way round but by the 1960's the convention was live on the left and neutral on the right. This was eventually made compulsory.
However, in Argentina where this socket is also used, the polarity is the other way round.
Or was this socket only intended for 240V use in the U.S?

Unfortunately the videokarma site doesn't allow access for unregistered users.
The "T" configuration outlet is officially used in Australia for extra low voltage applications (<32V) and has become very popular in recent years for 12V use in boats, caravans etc. However, its original use in Australia was for 32V DC farm lighting plants. Only a few days ago I found an article in a 1920's issue of the U.S magazine "Popular Mechanics" showing its use for the same thing. Readers were advised to use it so as to maintain correct polarity for the radio plugged into the outlet. Again, another U.S socket adopted by Australia.

The T configuration was used as the 12V charger connection on older fire trucks for years. A receptacle was mounted on the tailboard or battery compartment. Most newer trucks have an onboard charger/maintainer supplied by a 120V shore cord. Our club buys and restores old fire trucks, and we have a box of these plugs & receptacles. The older trucks, if you started the truck and drove out with the charger connected it would just pull out. Newer trucks have auto-eject inlets that have a n ejection pin that pushes the plug out when you turn the ignition on.

We did the same thing when I was a plant engineer at Beech Aircraft Corp. in Wichita, except that we used crowsfoot receptacles. The old-school management thought it would keep the workers from stealing power tools, but most guys knowledgable enough to use a power tool knew how to replace the plugs! We finally did a mass changer-over to standard NEMA 120V grounded outlets around 1977, which entailed replacing thousands of the old crowfoot outlets throughout numerous factory buildings.

Here's that crowfoot plug as seen in a patent issued in 1916. This patent looks like it invented the 3 pin grounding plug, and this example in the crowfoot pattern. This inventor worked for Hubbell.

This is absolutely astounding! At long last we see the real origin of the Australian plug and I can continue piecing together its history.
It is now clear that it was intended for ordinary domestic 120V use in the U.S, and we simply used it on 240V in Australia as was also done for a while with the non polarised version of NEMA 1-15.
Next question is, was the NEMA 1-15 invented before or after this? If before, I can see why the 3 flat pin plug did not become the U.S standard (much annoyance in not being able to plug in existing appliances with 2 pin plugs). However, had the U.S emphasised earthing of appliances earlier than it did, both countries could well be using the same plug today.
Thank you for this fascinating part of history.

It's hard to really tell from digging around the US patent office, but I see a 2 prong NEMA 1-15 plug mentioned a year earlier than the crowfoot 3 prong Aussie style plug.

Looks like this is the case, that crowfoot outlets post dated the 1-15 and the crowfoot didn't allow the use of 1-15 plugs. I did see later on a 1-15 outlet with a 3rd flat pin, looking like |_| but as we know, it didn't get accepted.

can you identify this 240V with ground receptacle...name, manuf, purpose, etc...

I am still an young one but from what I know that is not a 240 Volt receptacle
It is a tandem/Parallel Outlet the older plugs were a tandem blade design and modern plugs are a polarized parallel design (That outlet not being polarized)

The newer design of that outlet is polarized and both slots look like a 20A T slot receptacle

Thanks for the reply but did you note the slot offset is not like what was or is commonly seen.