old wiring

[rumplestiltskin]

I've just moved into my "new" house last week, think it was built in the 60s. a lot of the wiring is kind of rubbery coated instead of pvc, the earths are not copper, and look like aluminium. Can anyone tell me if it is/was aluminium earths that were installed about that time, thanks...and is there anything I should watch out for?

 

[ban-all-sheds]

Not sure about the aluminium bit - could be, or could be tinned, but the rubber insulation is a Bad Thing™ - it's well past its expected lifespan, and in places could be dangerous. The problem is that poking around to see what's there, and what state it's in can make things worse if perished insulation which was holding together crumbles when you move it.

If, as far as you can tell, the rubber cable is widespread then I'd suggest a complete rewire.

 

[dingbat]

The insulation is almost certainly VIR (Vulcanised India Rubber) [Or VRI, (Vulvanised Rubbber Insulation) as Approved Document P, has it.] It was phased out in favour of PVC in the sixties. The earths are tinned copper.

Likely Problems:
Imperial sized stranded cable, with different current-carrying capacities from modern cable.
Undersized earths compared to modern standards.
No earths in lighting circuits.
No main or supplementary equipotential bonding.
Insulation embrittled by exposure to heat/light, etc Often leads to exposed conductors at terminations.
Possible reduced insulation resistance values.

If the rest of the installation is as old then it will likely be inadequate (and inadequately protected) for modern usage. You may find an undersized and obsolete form of main fuse, poor or missing main earth connection in unsleeved braided tinned copper and either a single 2-4 Way fusebox or else several switch-fuse units as circuits have been added. The accessories (switches, sockets...) are also likely to be old and nearing the end of their life.

And I'm sure there's stuff I've missed...

It is generally considered inadvisable to work on circuits wired in this stuff - almost any electrical contractor will advise a complete rewire and many will refuse to carry out any work at all (extra sockets, etc) without replacing the circuit cables.

I'd advise you to get a couple of professional opinions.

[Written while b-a-s was posting his much more succinct response!]