13A Plugs old and not so old

[emeritus]

MK patented the flipper grip cord grip, and so would have had exclusivity for 20 years. The patent would have expired at least 10 years ago, and I have seen a number of recent plugs by other manufacturers that have this type of grip.

[turretslug]

I had a suspicion something like that might have been the case- I'm something of a fan of simple, effective production engineering, this is sure of a place in my anorak's rainy day virtual gallery of cleverness.... Having recently done a "safety vetting" at my sister's house (a quite incorrigible acquirer of antique fitments) and found plenty of 13A plugs with cord grips that were either entirely missing or uselessly loose, it's a shame that this (near-as-dammit!) fool-proof design wasn't more widespread.

[Alistair D]

A couple of TL branded quick connect plugs from my collection. I reckon that they are around 30 years old but have no recollection of when or where they were bought.

As can be seen in the first and last pictures, the manufacturer even incorporated a wire stripper.

Al

[Techman]

I can’t think that I’ve ever seen that type of plug as shown in the previous post #92, remarkable with a wire stripper!

[stacman]

I have used those plugs in post 92, sure I've got one somewhere in the house, probably in the loft attached to something.
I know that this is technically a 'vintage' forum, but a major wholesalers today, noticed a recall on a product, see if you can spot the reason for the recall?

[julie_m]

Oops! The pass-through socket doesn't seem to be earthed .....

[TonyDuell]

My guess is the problem is the plastic 'earth pin' (shutter opening device or whatever it is called). This would mean anything plugged into the 13A socket on the back of the unit wouldn't be earthed. I don't think I need to explain the danger of that.

[stacman]

Top marks to Julie, Just noticed on the counter, seems incredible that it got past the design, production, and actually on sale, nowadays.

[WreckTangle]

It was probably designed and manufactured in a foreign country where standards relating to correct earthing and fuse ratings are less rigorously adhered to, if they exist at all. I have seen some real horrors, such as a moulded 13A plug with no integral fuse. My favourite, which I must admit I still use frequently, is a cheap universal travel adapter bought on the Continent which in order to use in a 13A UK socket you place a small plastic "key" into the earth socket thus releasing the safety-shutter to enable you to ram the round two pin plug into the oblong holes. Works though!

[Station X]

Here's a couple which have been mentioned, but not pictured, I think.

A Permaplug and a Marbo.

Available FOC to a serious collector!

[Station X]

A 13A socket designed to fit on a round conduit box. I have two of these.

[winston_1]

Originally Posted by Alistair D

I collect those legrand plugs. They were available in white, red, green, yellow, blue and black.

And brown. Many organisations put their own logo on the back including the BBC. I had a brown one with BBC on once. I may still have it on a lead somewhere.

[winston_1]

Originally Posted by mole42uk

Surely they must have been 15A plug tops? AFAIK there were never any round-pin 13A ones. I've never seen a fused 15A plug top though.

I've just found the wiki entry that says BS546 plug tops could be made to accept BS646 fuses - of a maximum rating identical to the rating of the connector.

They are plugs. Plug tops are the covers that are screwed on.

Yes there BS546 plugs with fuses in the 5A and 2A sizes.

[Focus Diode]

Re post #87 these appear to have been introduced in 1973. The original version had white insulators which was changed to black in later years.
I've also seen a version branded Morphy Richards.

Brian

[G6Tanuki]

Originally Posted by Station X

A 13A socket designed to fit on a round conduit box. I have two of these.

I used to work at a site that had hundreds of these: built in the early-1950s to "Ministry of Public Buildings & Works" standards [look for the thin galvanised-steel window frames]. Every 13-amp round outlet was a conduit-fed 'radial', with its own 15-amp rewireable fuse on a series of big "BILL" switchpanels, one per corridor.

Apparently when originally installed the outlets had all been circular 'metalclad' 15-amp 3-pin but had been replaced with the MK round 13A sockets during a 1970s refurbishment. Someone had - conveniently - added blobs of appropriately coloured paint to the heads of the socket-retaining screws to indicate which phase fed a given outlet.

[Tractorfan]

Hi,
I have a 13amp round conduit box socket, plus a couple of 5 and 2 amp ones.
Cheers, Pete.

[Herald1360]

Originally Posted by Station X

We had those plugs in the council house I lived in as a child. Fuse ratings other than 13A were available and they were coloured coded. The fuse had a nasty habit of snapping off in the wall socket leaving a length of fuse wire protruding which could shock the unwary.

By the 1970's the plugs were becoming increasingly expensive and it was a relief when the house was rewired with standard 13A sockets. This job wasn't as easy as it sounded as the sockets were mounted on round conduit boxes which had to be changed for square ones.

"Sorry sir/madam, the parts aren't available for this old......." was and is ever the way to upsell an otherwise relatively cheap upgrade or repair.

Cynic? Moi? Naaaahh!

[Station X]

I have to disagree. Availability of the plugs and fuses wasn't a problem. Woolworths stocked them. There was no attempt to force people to upgrade to 13A plugs and sockets.

These plugs were rubbish.

They were expensive. From what I remember they cost three times as much as a standard 13A plug. I suspect the maker had a monopoly on the plugs, sockets and fuses. They sold the sockets cheaply to local authorities building houses after the war and made money by selling the plugs to tenants at inflated prices.

They were fragile, breaking easily if dropped.

They were dangerous. Often the screw threads would strip. and as a result the top would come off in your hand, as the flex wasn't threaded through a hole in the top. You'd then have all three pins exposed and sticking out of the wall. More common was for the fuse to break off in the socket leaving a live piece of fuse wire exposed just at toddler height. Even with the socket removed from the wall it was difficult to extract the remains of the fuse.

I never saw a switched version of the socket.

By the 1960's one socket per room wasn't enough. There were no multi-way adaptors or multi-way extension leads available for the system. My father would make his own adaptors by screwing the bottom half of one of the plugs to one side of a piece of wood and a 13A socket to the other. Three wires through a hole between the two completed the job.

As for the conduit boxes it would have been difficult to manufacture a switched single or double 13A socket to fit on a round conduit box, so square and oblong ones became the norm.

[Tractorfan]

Hi,
DS did make a switched socket that fitted into a round conduit box, but there wasn't much room for the wiring. It must have been fun getting two sets of 7/.029 cores in there! The fixing holes on DS sockets were slanted the opposite way MK sockets, I noticed.
Cheers, Pete.

[Station X]

Interesting. I wonder if the same thing was done with a 13A socket?

As I remember it round conduit boxes came with a threaded boss for the conduit attached to them. Did they make different versions depending on whether the conduit ran vertically or horizontally? If they didn't the flex could have emerged horizontally or vertically. Now I think about it I'm sure I've seen sockets mounted ar 45 degrees.