Can a mains plug be any simpler?

[Tractorfan]

Hi,
Thought I'd share this as it's American Independence Day.
It's a (probably very old) US mains plug that is very simple with insulation piercing connections.
It is UL approved and marked B&S. Suitable for nothing more than a table lamp or similar, I think.
Cheers, Pete.

[TonyDuell]

I had a US mains plug -- may still have it -- that was even simpler. Like that one it was an insulaton-piercing design onto what they call 'zip cord'.

The body was cuboidal with a slide-on lid on the opposite face to the pins that locked when closed and took a screwdriver to release it (I don't think you were supposed to ever do that). You put the end of the zip cord into a slot in the moulding at the end that the lid went on from, then bent it over so it ran over the insulation piecing spikes and slid the lid on. That forced the cable onto the spikes and made the connections.

[barrymagrec]

I`d suggest that the old 2 pin 5 amp Clix plug was even simpler, it didn`t even have a cover screw, the cover just screwed down and clamped the wires into the pins.

[Dave Moll]

You beat me to it, Barry. I was about to see whether I could lay my hands on one from my collection prior to posting.

[Tractorfan]

Hi,
Oh yes, I'd forgotten about the Clix plugs.
Cheers, Pete.

[Tractorfan]

Hi,
Here's a Clix 5 amp plug as mentioned in post 3. Although it's not marked as such, oddly.
I also have a Clix 15 amp two pin plug which is slightly less simple, just one screw (plus the cord grip).

[Vintage Engr]

Originally Posted by barrymagrec

I`d suggest that the old 2 pin 5 amp Clix plug was even simpler, it didn`t even have a cover screw, the cover just screwed down and clamped the wires into the pins.

Indeed, a great plug, if you're not into health & safety!

Way back in the early 1960's when I was at Rediffusion, all new TV receivers came in without a mains plug.
Believe or not we actually soak-tested all new sets before delivering them to the subscribers. So, instead of using a lot of Safeblocks on the soak benches (which we only had on our own benches) we used the Clix 2-pin plugs.
If you were really unlucky, someone had slightly unscrewed the top cover, so the top would come off & you'd inadvertently 'get a belt' when unplugging...!

I'm still here to tell the tale, & we had a concrete floor.

David.

[usradcoll1]

Originally Posted by Tractorfan

Hi,
Thought I'd share this as it's American Independence Day.
It's a (probably very old) US mains plug that is very simple with insulation piercing connections.
It is UL approved and marked B&S. Suitable for nothing more than a table lamp or similar, I think.
Cheers, Pete.

Unfortunately a poor excuse for a US mains plug! U/L must've let that one slip through. Possibly for loads not exceeding 75 watts @ 120 volts. I only seen on of them. I replaced it!
Dave,

[Nuvistor]

On equipment supplied to the UK by the USA computer company I worked for, these Hubble plugs were always supplied. Both 110 and 230 volt in the photos, I found them an excellent plug.

[TonyDuell]

Was that DEC/Digital? I've got dozens (literally) of those Hubble plugs in use here on my PDP11s, disk drives, etc? And a few of the cable mounting sockets.

I agree, those Hubble plugs are excellent. I was talking to a chap from the States and described (old) MK as being essentially the UK equivalent to Hubble -- excellent and safe mains plugs, sockets, etc.

[Nuvistor]

No in wasn’t DEC but it had various names over the years, it started out in the 1960’s as Interdata.

[usradcoll1]

Originally Posted by Nuvistor

On equipment supplied to the UK by the USA computer company I worked for, these Hubble plugs were always supplied. Both 110 and 230 volt in the photos, I found them an excellent plug.

Hubbell designed the flat blade plug over 100 years ago, which with slight variations, is still used today.
The 120 volt, 15 amp plug shown is a mirrored view. The neutral blade is on the left, the live is on the right.
Dave, USradcoll1, retired electrician.

[G6Tanuki]

Those Hubbell 3-pin plugs are rather good, in times past when I was designing some gear I specced a couple of such outlets, the recessed panel mount variety, on the front of my kit, it was a great way to give visiting field circus techies a power supply that was easy to access and so stop them fishing around in the back of the rack to find a socket for their datascope and inadvertently disconnecting something important in the process!!

[note: field-circus was the nickname we gave to field service technicians, one particular company providing them seemingly recruiting their tech staff on the basis of fools and jokers.. ]

[TonyDuell]

My minicomputers are fortunate that I don't let Failed Circus anywhere near them, although I've had to correct many faults caused by them before I owned the machines.

Getting back to US mains connectors, as soon as I obtained some extra ones (they were not easy to obtain 30 years ago in the UK), I made up a cable with a US 234V plug on one end and a BS1363 trailing socket on the other to run my 'scope or soldering iron or... from a spare socket on the DEC power controller. And the reverse, a cable with a BS1363 plug on one end and a US 234V socket on the other to run power supplies etc removed from the PDP's on my bench for testing. Both have saved a lot of time over the years.

[arjoll]

Originally Posted by usradcoll1

Hubbell designed the flat blade plug over 100 years ago, which with slight variations, is still used today.

He also (inadvertently) created the AS/NZS3112 plugs!

https://en.wikipedia.org/wiki/AS%2FNZS_3112#History

[usradcoll1]

Originally Posted by arjoll

He also (inadvertently) created the AS/NZS3112 plugs!

https://en.wikipedia.org/wiki/AS%2FNZS_3112#History

The factory, where I worked, starting in 1965 still had those plugs and receptacles. It about 1970, they changed them to the new Nema 5-15, still in use today. Those old devices were still available, but were expensive, because of limited demand!
Dave, USradcoll1.

[emeritus]

Only partly correct about Hubbel inventing the US flat pin plug . The pin dimensions and spacing are indeed those devised by Hubbel, but flat pin plugs per se of different dimensions were in use many years before Hubbel made his type.

I discovered this by chance some years ago when looking on-line for info on the "Chapman" connector, a power outlet design that was in widespread use in the US in the late 19th Century. Google produced a link to an issue of the "TEN Trade-Mark Reporter" that was then available as a downloadable PDF from Google Books, but has since been removed. It relates to Hubbel's unsuccessful attempt in 1919 to prevent other manufacturers from selling plugs that would mate with Hubbel's sockets. He failed because the other manufacturers did not include Hubbel's incredibly successful patented detents that were designed to stop a plug from inadvertently falling out of an adaptor screwed into a pendant ES lamp socket. Hubbel's first design used round pins with jackplug-like annular detents, his second type used "tandem" flat pins oriented like the L and N pins of a UK 13A plug. The final design with parallel pins came out in 1912.

I did revise the info on the Wiki pages on AC Power Plugs to reflect the summary of the development of mains plugs in the US that is contained in the law report.