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Lead Wiring...

It'll probably be fine until disturbed. But in a 'new' house, people tend to want to fit new lights, switches dimmers etc. That's when the fun starts.

Reply to
Dave Plowman (News)
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I forgot to mention something. In 2003 an electrician added 4 downlighters to the circuit when the bathroom was re-done, and has left his safety tested sticker on the fusebox. My Dad reckons that the original 5 Amp round pin wall sockets would have been connected to it, and that the 13A modern sockets may well all be on it. He could only see the one obvious cable running upstairs. As for the sheath being at 120V - doubt it. I didn't get any kind of shock, mild tingle etc when I scratched a bit of paint off the surface to reveal the metal last week. The metal was also very shiny and not in any way corroded. The cable was also stone cold, so not running warm at all. Anyway, I think my Dad's going round there next week to test the cables and see if there is an imminent problem. I think we might tackle a re-wire over Christmas unless the results of the cable test indicate a more pressing need. In the meantime, we'll be advising my sister to not use a hairdryer, kettle etc upstairs.

Reply to
Matthew Durkin

In message , Peter Scott writes

Prolly enough for a pint of beer (or two)

Reply to
raden

My Dad seemed to think it would be paper insulated, not rubber. Apparently it lasts a long time so long as it is never allowed to get damp. Not seen any lead blobs though! There are definitely lead junction boxes in this installation...

Reply to
Matthew Durkin

Pretty sure I've seen rubber - but it was a looong time ago. I suppose if there were a rubber version, the sheath would have to have been wrapped around cold and an unjoined seam left. Was there such a thing or have I smoked too many mushrooms? - not much chance of seam welding lead in contact with rubber I would have thought. Or was there a magical way of cold drawing a lead sheath tight around the cores during manufacture?

The paper variety would make sense - a larger version was the standard for supply cables underground. Still plenty of it in service in London - saw a lump being replaced 2 years in Sutton just outside the station. Obviously wasn't very serviceable at the end due to the number of times the lights went out in the upper High Street(!).

Cheers

Timbo

Reply to
Tim S

On Mon, 23 Aug 2004 21:59:39 GMT, "Matthew Durkin" strung together this:

Somewhere there'll be a long list of failures if it really has been tested properly.

Reply to
Lurch

In article , Mike Tomlinson writes

Why's that? Is electricity any more dangerous now than it was then?

:-)

Reply to
Frank Erskine

Lead does not stay bright in air. When you took the paint off you took the corrosion off with it.

sounds like you didnt understand what was said on that point.

Your Darwin Award has been reserved for you.

NT

Reply to
N. Thornton

Err. so there was air under the paint and thus corrosion, what is the point of paint then ? There was not corrosion because the paint had kept the air from the surface of the lead, as it's designed to do !...

Reply to
:::Jerry::::

This wiring may have been installed in the 50s or earlier. I remember watching it being installed in my grandparents house. We had to completely rewire when we took over the house in 2000. Typically the outer case is soft lead and the inner insulation is rubber. When air gets at it the rubber is liable to perish. It then becomes hard, brittle and prone to crumble, reducing its effectiveness as an insulator.

What could you do with it?

  1. Do not disturb. Ie. do not touch, move, change any light fittings or switches etc ... and hope it lasts until you can replace it. Clearly, not a long term solution! But any disturbance will aggrevate the problem.
  2. Get it tested. You are almost certain to be told its had it. But you really want to know is if any of the circuits have lowered resistance when all switches are off. Any small current leakage would be a sign of trouble building up and will only get worse.
  3. Rewire - to meet today's needs, which are likely to be different from those of 50 years ago.. Leave the old stuff in place - just disconnect it all.

Is it just the lighting circuits that are lead coated? What is the the state of the power socket wire? They might be a different type of cable - with itsa own problems.

David H-S

Reply to
David H-S

I have a piece here, that I had kicking around and have just disected it out of interest. The inner insulation is definitely rubber, still in good condition and flexible. This piece was not connected anything when I found it and was cut back so other than the cut end, the rubber wasn't exposed. No sign of any visible seam on the lead sheath, inside or out. After pulling the wires out of the sheath, the following is printed on the insulation of the live: "... 250 VOLT CMA (REGD) BRITISH INSULATED CALLENDERS CABLES LIMITED LEIGH AND HELSBY ENGLAND..." The conducters have 3 strands of copper each, not sure about size.

Reply to
John Armstrong

Possibly, though we cant simply assume that option. Any case, the earth bond can not be assumed to be gas tight.

I assumed decorative, do you think there is a different purpose?

NT

Reply to
N. Thornton

In article , John Armstrong writes

The BICC plant at Helsby is still going.

Reply to
Mike Tomlinson

Hmm - I should ask my Dad - he did a stint with Callenders (before BI merged I think). They had a most cool 1 MV test rig for insulation testing

- on big insulators right up in the air apparantly.

Reply to
Tim S

No argument there, I was just questioning your reasoning behind the paint remark.

Decorative is a secondary function, protection is the prime function, even though it's not always used as such IYSWIM.

Reply to
:::Jerry::::

In an unused cellar I don't think the paint was there for decorative purposes.

Also - I understand fully all the points that have been made on this forum, especially the ones regarding carbon build up around where insulation is breaking down etc. My point about the cable being cold was merely observational!

point taken about the darwin award. I hope it doesn't come to that. I live

250 miles from my sister, and my dad works 12 hour shifts plus 2 hours travelling. He's also got his floor up at the moment treating woodworm. There's only so much we can do!

I think one of the most interesting things to come out of this long discussion is that those who actually have some of this cable have it in good condition. There are no sings of any decomposition of the cable at all in this installation. I'm not saying it's good. But it has been running fault free for maybe 70 years. My Dad will be over at my sisters with a megger asap to see if there's any imminent danger, and he'll also be ripping out the lead cellar lighting. There will still be the laed feed into the house itself though, but at least then we'll be in a better position to know how bad it is!

Reply to
Matthew Durkin

Thanks David - nice to have some sensible suggestoins! We'll be doing what you said and rewiring as soon as we have a chance!

Reply to
Matthew Durkin

The insulation will almost certainly be butyl rubber. It has a tendency to degrade seriously where it is exposed to air, i.e. at all joints, switches, plugs, etc. and becomes brittle, crumbly, and powdery. Cut a length in half and you'll probably find the insulation is perfect! There can also be problems with earth continuity.

Butyl rubber was a common insulant within the electricity supply industry 60 to 70 years ago, used for lead-in cables to properties. Much has been replaced, although it still turns up in predominantly rural locations.

Lead sheathed cable is now considered to be unsafe for electrical installation work, and should be replaced ASAP.

Reply to
wanderer

Well, lead is commonly used for roof flashings etc and isn't painted, so I can't see any reason to paint it inside. It sort of oxidises on the surface and this acts as a protection for the rest anyway.

Then get in a pro?

You need to do a physical inspection of the ends at a switch etc and check if the rubber insulation is perished - and I'll bet it is. An insulation test may not show this up, though.

It's probably 50 years old plus.

Reply to
Dave Plowman (News)

its bound to be cold, once it gets to the stage of heating up there would likely be a fire within hours.

You cant assume its fault free, I think its more likely there are leakage currents running here there and everywhere. On a 5A wire fused circuit you would have to have more than 1.2kW dissipated by the cable for a long time (like an hour plus) before the fuses would start to think about blowing.

Right. If youre truly unable to do the work you could buy a reel of flex and a few sockets and get yourself electricity to the rooms that way. Crude, but if it were me I would not want to be running mains down that old stuff, not for a minute. I think this would be much better use of a couple of hours than trying to megger the installation, when it cant have more than 1% chance of passing.

Even by 1930s standards an installation like this would be condemned.

Regards, NT

Reply to
N. Thornton

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