Wiring below plaster in 1969

Aug 25, 2015 20 Replies

I have read about safe zones and 30mA RCD protection which I believe is specified in the 17th edition for cable less than 50mm from the wall surface - assuming no metal protection.



My house was built in 1969 so I guess to the 14th edition. What would have been the regulation then concerning wiring underneath plaster?


probably no regulation. I tended to use metal covering strip, having done my own risk assessment

I don't think any.

I've just leafed through sections B and C of the 1970 (metric) amended version, and can't see any.

In good work steel conduit would have been used for switch and socket drops, even if T&E was used. In rough work you might find wire anywhere.

Owain

I watched a house being built next door in 1964. The wiring went from the first floor ceiling diagonally across walls to the power points. They might have saved a couple of metres of cable on some outlets.

My house was built early 70's, I've found the old cooker-point cable was at 45° and one lightswitch drop was a bit on the piss, but probably just stayed within the combination of the safe zone vertically above the switch and the safe zone in the corner of the room.

Yep. ISTR it was it the 16th edition that introduced the safe zones or at least defined them.

'course, the applicable regulations are all very nice, but they're at the mercy of the sparky actually DOING the work - plus every single cowboy and enthusiasm-over-clue DIYer who's been near it in the intervening 46 years...

I think that's fairly standard :-)

Cooker cable is after all comparatively expensive.

Owain

And who in my kitchen actually plasterboarded over a lot of the sockets (including the hideen unfused spur to the pelmet lights)

Owain

No specific regulations as such.

Normal practice then on new installations by reputable installers would have been to cover the cable with galvanised metal strip. Surface depth of plaster was variable but plaster depth metal boxes were the norm then but rarely would the cables be more than 50mm deep more likely 10 to 15 mm .

Sometimes in 'local authority spec' properties conduit was used instead of metal strip for cable protection.

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Wouldn't one of those cheap stud/metal/cable finders solve the problem? Mine picks up live cables, no load, easily.

Metal capping will keep the cable in place and stop it from from being sliced with a trowel while being plastered.

When once the wall has been plastered galvanised metal capping provides NO protection from nails and screws.

Agreed but i was stating normal practice, protection was not implied, however i have seen cables 'secured' to unplasterd walls with only nailheads by less reputable 'installers'.

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I found it did cause a masonry drill to pause - then I could see waht was inthway.

Certainly not from a picture hook - the sort with very thin hardened nails. Might sort of stop a masonry drill for a short time, though.

I found it did, so drilled the hole elsewhere.

Depends on the SDS drill :-)

The Bosch would not know that it was there.

True - although I was more thinking of the masonry drill of the time. But modern universal bits would probably go through it too.

I generally only use the SDS for larger stuff. For most things needing say a No8 or smaller wall plug, the ordinary drill with a universal bit is easier to drill a hole in the right place. On London bricks, at least.

1987 Amendment to the 15th ed., IIRC.

Ok - once again thanks for all the informative replies.

It looks like the original wiring was carried out between the ground floor ceiling and 1st floor with short pieces of steel conduit to the upper and lower wall sockets. Various additions have been made with T&E just below the plaster surface. The "CU" is a 4-fuse Wylex. It is unlikely that anyone buying the house after I depart will do anything other than a complete re-wire.

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