Hello all,

When I was writing the new  ”The Part P Doctor” book, the project, as you know, revolved around the actual rewire of an old house.  The house in question was a large early 1930’s detached home.  It had been rewired in the past but as I was doing more work I stripped out these little gems to show you…...Lead, VIR and TRS Don’t worry if this is all double dutch, just carry on reading!

Starting at the top you can see lead covered twin cabling.  This went out of use in the 1940’s.  It consists of copper wire covered with tin, then rubber and finally a lead sheath.  This sheath was used as a cpc. Lead oxidizes very quickly, going black. However, I have scrapped a nice shiny bit for you in the picture.

Next down is old steel conduit with single wires fitted.  This was very popular in the 1930’s and 40’s.  The conduit is the cpc. The wires are called “Vulcanised Indian Rubber” wires.  Here, we have again tinned copper wires, rubber covered and topped off with a cloth tape or covering. Again, I have unwound a little of this to show you.

The last one is later again, perhaps up to the end of the 50’s.  It is called TRS which stands for “Tough Rubber Sheathed”.  Again, the wires are tinned copper but the cable is the same as you use today except you now use PVC instead of rubber.

I don’t know why they tinned the copper then but it must have had something to do with a reaction between copper and rubber.  All these old wiring systems had definite life spans for sure.  Th old rubber dries and crumbles away and insulation faults result!  My advice is to not touch anything that looks like this.  If you do disturb it and it all crumbles before your eyes, don’t say I didn’t warn you!  Finally, if you are just passing by this site and not an electrical person, do look out for this stuff in your home.  If you find it, please, please call out an electrician.  I am sure there are still many thousands of miles of this stuff lurking around out there!

The final question from customers and students alike is, “How long does PVC wiring last?”  Well, having worked in houses recently, built in the early 60’s I would say “forever!”  Remember the only thing that can kill PVC wiring is heat from bad connections or general overloading.

Bye for now……