Electric installation.. how old???

[Gerd Busker]

I've been wondering about this for a while...

Flat: 4 storey building, ex-council in Putney

Wiring: Twisted grey metal (harder than copper) wires with rubber and a hint of cotton around it. Crumbling, with one run burnt out in a distant past.

Earth bonding: Metal pipes (bloody hard stuff)

CU: 6x 5/15/30 Amp wire-yourself fuses, isolator switch on the right. No provision for grounding (done outside the CU).

The supplier side is much newer with good quality feeds and a propper ground wire.

It's all going, but just out of curiosity can anyone offer a guess how old this stuff is? I've played with electrics since I was a child and I've never seen something this old.

G.

[s--p--o--n--i--x]

I'd say 1930's..I used to live in a house that was built in the 30's and it had wiring just as you describe.

The worst I saw in a house was using fabric covered cable. Junctions were formed using Oxo tins...wires were brought in through holes punched in the sides, twisted together and the whole lot filled with tar!

sPoNiX

[BigWallop]

Maybe around the sixties mark, but it may have been more recent if done by council.

[Broadback]

Fascinating how things change. My parents had their house wired for electric soon after WW2, about 1950, the electrician used lead covered cabling cleated to the walls, and of course, surface mounted switches and sockets.

[N. Thornton]

In message [e-mail] From: Gerd Busker ( [e-mail]) Subject: Electric installation.. how old???

Sounds like a standard round pin install. Pics of the accessories would help date it.

BTW such a system is normally still good for 12v use, so you could if you want keep the sockets and fuseboard, but supply the fuseboard from a 12v power supply. Now as well as the new mains system you can also use the old one to run plug in 12v lights and various small appliances with 12v connctions on - which a fair come with. At 12v, 15A sockets will supply upto 180w each, 5A 60w, and 2A 24w each.

Alternatively you can use the old socket wiring to route phone or intercom services, or even data if it works ok.

Are the lightswitches decorative? If so there are ways to retain them and make it all safe if you want.

Just options.

NT

[The Natural Philosopher]

Sounds like my mums 1953 installation.

Metal conduit and rubber cable is post war, but not by much I think.

[Gerd Busker]

Ha, the house as an extension of the car, rather than the other way round :)

Actually, it looks like most of the switches and sockets have been replaced at some point in time. As has part of the kitchen cabling.

It's all going. The fusing configuration is unsafe, the cabling is almost all gone and the new CU goes up this weekend. Some demolishing is going to have to happen to the old metal box that the CU sits in to fit the new one.

Interesting dilema: How do you drill holes into concrete behind the CU when you've no power?

G.

[chris French]

In message , Gerd Busker writes

Hire a nice big F-O cordless SDS drill - they do hefty 24V jobbies that I see pro's using a fair bit.

[Dave Plowman (News)]

After pulling the main fuses and removing the tails which were to be replaced anyway, I simply wired a temporary RCD socket direct. So I stole a few pennies worth of electricity. I would have done this after the meter, but that had to come off as well.

[s--p--o--n--i--x]

Fabric covered rubber was def available pre war.

[Dave Stanton]

I borrow my nieces husbands, Bosch 24V SDS drill, he's a plumber. Best thing she ever did was bring a damm good plumber into the family.

Dave

[The Natural Philosopher]

Yerrs, but IIRC metal conduit ws not - much. The frst sfaey installations, using metal conduit as earh, seem to have been post war - in domestic houses anyway.

Before that they seem to have used lead shething.

[Dave Plowman (News)]

And before that wood conduit. ;-)

[N. Thornton]

In message [e-mail] From: Gerd Busker ( [e-mail]) Subject: Re: Electric installation.. how old???

Cordless is best, otherwise its liven up the CU while you do it (not recommended), use the old rawldrill approach (small chisel, whack, turn, whack, turn), or if the crete's soft enough a hand drill. Or else glue the new thing on instead of screw, or move its fixing points slightly. I'll leave out the dynamite option, as its out of favour these days.

NT

[Nick Atty]

Which was, I suppose, meant to work as an earth. During my early youth there was an "interesting" phenomenom at my parent's where the lights would sometimes dim, accompanied by a crack. It turned out that the insulation in a piece of this cable had failed, the lead sheath was live, and was earthing itself briefly at intervals to the lead gas pipe it ran alongside - slowly making a nice spark-eroded hole in it...

There wasn't a good enough route to earth from the sheath to blow the fuse, and the contacts to earth through the gas pipe weren't long enough for the wired fuse in those nice steel boxes where the handle interlocked the lid.

Luckily it was found and fixed before the inevitable explosion, or I probably wouldn't be telling you about this.