Period Electrics

[MatthewC]

I've had some fun in the last week with electricity. Firstly I found bare mains supply cables amongst the ivy on my fascia - see http://houseintheenchantedforest.blogspot.com/2010/10/taking-breath-after-first-week.html. I did get it all down and I am still alive, with an ivy-free wall and roof.

Then I did not trust the internal system at all, as I had round pin (15A and 5A) Bakelite sockets downstairs, and old wires everywhere. So I had someone in to disconnect everything and fit a new circuit breaker board supplying four new sockets and the two storage heaters only, so that I had something I could trust.

Today, whilst demolishing a cupboard in a bedroom, there were 13A sockets supplied by what looked like normal cable - about 1cm x 0.5cm, clipped external to the wall. When I severed this cable, I realised that in fact the cable was sheathed with lead! I did not know that such a thing had ever existed, and am amazed that anyone would connect a (relatively new) 13A socket to such a thing. Has anyone any idea how old this cable might be?

NB on one of the cupboards downstairs, we found some shelves lined with paper from May 1954...

See also http://houseintheenchantedforest.blogspot.com/2010/11/second-week-progress.html for photos of my roof structure.

 

[Lime]

Has anyone any idea how old this cable might be?

Common between 1910 and 1935.

 

[Feltwell]

Lead covered cable can be later than that - this town didn't get electricity until 1940, not sure if this house was connected straight away.

Today I found lead covered cable in the roofspace whilst running some new cables, thankfully it had long since been disconnected! My last house had rubber covered cables, again long since disconnected - when they were disturbed the insulation just crumbled to dust. Terrifying to think there are houses out there with this type of cable still in use!

Then I did not trust the internal system at all, as I had round pin (15A and 5A) Bakelite sockets downstairs, and old wires everywhere. So I had someone in to disconnect everything and fit a new circuit breaker board supplying four new sockets and the two storage heaters only, so that I had something I could trust.

A very, very wise move!

 

[Flyfisher]

Hi Matthew and thanks for the update.

I think lead-sheathing used to be used on cables intended to be buried, presumably before the development of steel-armoured cables, which would make some sense if the cable was run along the outside of the house.

Sounds like a near-miss (fortunately!) with the external mains supply to the house. I'm not surprised it was condemned as unsafe by the electricity people. I've had some dealings with our local electricity supply people (EDF) and they told me that any cables to houses have to be insulated these days, even if the supply arrives on bare wires to the nearest pole, as ours used to before much work to sort things out.

All good fun though - and this is just your first week!

 

[philpjuk100]

In the 50s my parents house which was built between the wars was completely wired in lead covered cable and had "wilex"sockets and a wooden fuse box with big pot rewirable fuses.my dad noticed that with everything turned off the meter still turned! and found a warm cable under the stairs.We rewired in pvc cable from a new fuse box but not a ring main and with 5 and 15 amp round pin sockets.He wired my bedroom with its own fuse so when I played records too loud he could disconnect me! phil.

 

[CatherineB]

I love your blog, Matthew.

 

[Lime]

The early lead cable used paper for insulation (an excellent material if kept dry... used in very high voltage cable with oil for cooling and vastly superior to pvc) and if undamaged and not terminated in wet areas will still be good today.
Much of the distribution cables in London and elsewhere are lead and paper and may be supplying your house as I write!
Perhaps an alarming aspect of the domestic cables is that the lead sheath was not usually earthed when first installed.
An earth was not normally required nor thought neccessary.
My original dates of 1910-1935 were when most popular but, as has been said, may be found in houses before 1900 and as late as the 60s.
Lead was used for ordinary house wiring (as PVC is today) often replacing early wooden box conduited copper wire wound with cotton.
Rubber began superseding lead around 1935.

 

[Penners]

I've seen plenty of lead sheathed cable, but it has never occurred to me to ask this (rather ignorant) question: does lead conduct electricity?

Experts...?

 

[MdB]

208 nΩ·m

Now think where lead used to be often used in electronics Penners and then go to the back of the class.

 

[Gervase]

Cor, that battery's heavy...

 

[Flyfisher]

All metals conduct electricity, it's one of their defining characteristics.

 

[Flyfisher]

and a wooden fuse box with big pot rewirable fuses

We've still got one of those, but I've been installing some new circuits prior to an electrician coming out to replace it with a modern consumer unit and certify everything. I've not come across any lead-sheathed wiring although we did have a few bits of old rubber wiring, which was actually in surprisingly good condition when I replaced it.

 

[Lime]

we did have a few bits of old rubber wiring, which was actually in surprisingly good condition when I replaced it.

I've removed miles of black rubber cable in my past life and much of it was in very good condition.
Apart from oil and solvents, there are 4 things which normally caused it to disintegrate in service: Sunlight, heat, paint and ozone.
The sunlight, heat and paint are obvious but not everyone knows that when electric switches operate, particularly the older type, they create a spark.
Sparks in air produce ozone, hence the rubber on wires to switches were often hard and brittle while the rest of the cable was as new.

 

[Penners]

208 nΩ·m

Now think where lead used to be often used in electronics Penners and then go to the back of the class.

Er, please sir...solder, sir?

Cor, that battery's heavy...

 

[MatthewC]

Thanks everyone, especially Lime, for the informative (and amusing!) answers.

I forgot to mention that I also found a wonderful bit of flex for an electric fire. This looks like recent 15A cable with an in-line join to the original woven covered flex (5A?), and no fewer than four other taped in-line repairs between that join and the fire (where I've cut it off!). Why didn't they cut those four out? How come there is still a house standing?

 

[FamilyWiggs]

I had a similar shock (no pun intended!). The last 2 sockets on a spur behind the plasterboard in my dining room had been connected with bell cable. :shock:

 

[Penners]

Well at least you know that, should the heating element fail, the warmth from the flex will still keep the chill out.

 

[robgil]

yhou know apart from things like the dangerous bell wire period electrics seemed to have done the job for many many years and although i am sure the odd inquisitive type may have gotten them selves electrocuted i am pretty sure it wasnt as bad as a present day electrician would have you believe, sucking in through the teeth can have an over exaggerated effect on just how bad something really is.
I think the problem rests with our power hungry appliances needing more oomph than old electrics could manage.

 

[Lime]

yhou know apart from things like the dangerous bell wire period electrics seemed to have done the job for many many years and although i am sure the odd inquisitive type may have gotten them selves electrocuted i am pretty sure it wasnt as bad as a present day electrician would have you believe, sucking in through the teeth can have an over exaggerated effect on just how bad something really is.
I think the problem rests with our power hungry appliances needing more oomph than old electrics could manage.

The biggest problem with older electrics is that many relied upon the cold water pipe (the mains) to provide an earth.
While the pipe in the street remains metal that will still work (although not comply with the regulataions) but if the water company or your plumber replaces the metal pipe for plastic the earthing and whole house is immediately made dangerous.
As for modern electricians.... tell me about it.
Many are just in it to make a few bob and quality and skill is often lacking.
Then there are those that think anything that hasn't been installed by themselves is "dangerous love", "don't comply" etc.
Unfortunately there are plenty who exhibit next to nothing in understanding of electrical circuits when they go wrong... but expect you to pay them while they are learning.
I could go on.........

 

[robgil]

yhou know apart from things like the dangerous bell wire period electrics seemed to have done the job for many many years and although i am sure the odd inquisitive type may have gotten them selves electrocuted i am pretty sure it wasnt as bad as a present day electrician would have you believe, sucking in through the teeth can have an over exaggerated effect on just how bad something really is.
I think the problem rests with our power hungry appliances needing more oomph than old electrics could manage.

The biggest problem with older electrics is that many relied upon the cold water pipe (the mains) to provide an earth.
While the pipe in the street remains metal that will still work (although not comply with the regulataions) but if the water company or your plumber replaces the metal pipe for plastic the earthing and whole house is immediately made dangerous.
As for modern electricians.... tell me about it.
Many are just in it to make a few bob and quality and skill is often lacking.
Then there are those that think anything that hasn't been installed by themselves is "dangerous love", "don't comply" etc.
Unfortunately there are plenty who exhibit next to nothing in understanding of electrical circuits when they go wrong... but expect you to pay them while they are learning.
I could go on.........

same with all trades i reckon, everyones an expert no matter how limited their knowledge. quick and cheap seems to be how things are done these days.