Quick history question - MK fitting design.

[Robin0577]

Can anybody remember which year MK changed from the curved plates and switch rockers to the flat square "Logic" range, and which year they changed again to the current "Logic Plus" design?

Also, when did solid core metric T&E replace imperial stranded?

I'm trying to work out which bits of an old house have been messed with and when, mostly for academic interest, I suspect it will all be pulled out and replaced anyway.

 

[RF Lighting]

I think logic sockets (the square ones) came out in the early 80's, and were superseeded by logic plus in about 1996.

Imperial cables were replaced with metric in the mid 70s.

 

[wundaboy]

MK Logic square style sockets first came out in 1975, though the same style switches were available earlier - I've got a 1972 catalogue which lists MK Logic (though they weren't called that then) rocker light switches, with all other accessories being the curved edge style with toggle switches which had been around since the early sixties.

As I remember it, the MK Logic sockets had a refresh around 1977/78 to change the shutter design (the original 1975 ones allowed a two pin europlug to be inserted without any additional mechanical aid) and then another cosmetic refresh in the early-mid 80s which removed the 'on' legend from the switches and framed the MK logo in the middle of the socket in a rectangle.

Logic Plus came out about 1998 I think?

Metric cable came in around 1969-70? The original 2.5 T+E (with 1mm earth) was horrible stuff, really stiff and hard to handle compared to the flexibility of stranded 7/029.

 

[ban-all-sheds]

The original 2.5 T+E (with 1mm earth) was horrible stuff, really stiff and hard to handle compared to the flexibility of stranded 7/029.

Which in turn was probably stiffer than the VIR it replaced.

Things like that show why it's unsafe to look back at the original date of an installation and say "by then they'd stopped using Imperial cable", or "by then PVC had replaced VIR".

People who had been working with the previous material for decades, and could still get it, would have been reluctant to change - I think we can pretty much guarantee that there were electricians still installing VIR for as long as they could still buy it, or Imperial PVC instead of metric.

 

[dhutch]

Things like that show why it's unsafe to look back at the original date of an installation and say "by then they'd stopped using Imperial cable", or "by then PVC had replaced VIR".

People who had been working with the previous material for decades, and could still get it, would have been reluctant to change - I think we can pretty much guarantee that there were electricians still installing VIR for as long as they could still buy it, or Imperial PVC instead of metric.

Certainly.

When I was looking a buying one house, built in the 70's using PVC, but had been extended (light for the cupboard under the stairs, etc) in VIR and bakelite. Presumably from the quality of the work as a DIY concern, but ofcause we would never know.


Daniel

 

[Robin0577]

Agree with you totally there BAS, but I was actually looking at this from the opposite direction as it were, i.e.

"This must have been done AFTER date X because this product wasn't available BEFORE then"

Less margin for error in that direction I think?

 

[sparkwright]

The red bit on the switches of the square cornered sockets were more textured on the older ones.

The colour of earth wires/sleeving changed from green to green and yellow around the mid 70s.

 

[securespark]

IIRC, the full square logic range came in in 1974.

I was invited to a customer clinic to work with prototypes of the logic plus accessories in 1990 or 91.

Don't know when it was first marketed though.

 

[RF Lighting]

I remember installing logic grid stuff when I'd just started my apprenticeship and discussing the new logic plus grid switches at college in about 1997.

 

[securespark]

You whipper-snapper you!

By 1997, I'd installed my millionth socket and had worked my way through from the 2nd Ed. to the 16th. Aye. 'Appen.

 

[333rocky333]

The 1994-1996 Mk catalogue does not contain the logic plus range
and as said there were various changes to the original Logic range regarding the pin shutters, and the change from the oval to a sguare Mk logo on the socket face.

 

[OwainDIYer]

I recall Logic going to Logic Plus in 1997.

 

[ban-all-sheds]

You whipper-snapper you!

By 1997, I'd installed my millionth socket and had worked my way through from the 2nd Ed. to the 16th. Aye. 'Appen.

Interesting.

2nd edition was issued in 1888, and ran until 1897.

Allowing for child labour in those days that makes you about 120.

You should phone the Guinness Book of Records.

Before it's too late

 

[sparkwright]

I'm pretty sure the current MK stuff came out in 1996 or 1997, and the square cornered stuff was still available for a few years after.

In fact, the shower pull cords are still square cornered, as are the small surface sockets that nobody buys.

On a different note, I take it MK plugs STILL have those wrap round terminals?

 

[RF Lighting]

Yeah they do. They are horrible.

Duraplug that MK also make have normal terminals.