Many Homes In Glasgow and Paisley have old antiquated wiring.
Here’s some of the wiring types found.
If you suspect you may have any of these get in touch with HomeRewire right away.
- Paper insulation
- From the WW1 era
- Very rare now in domestic wiring
- Paper is somewhat hygroscopic
- Pre-war paper cable is still in service in distribution networks, and causes a good deal of downtime
- The polychlorinated bipehnyl (PCB) oil used in old paper insulation is toxic, and the insulation should not be handled with bare hands
- Common in 1930s for socket circuits
- Used as exterior farm cable well after that
- Lead sheath does not make reliable earth connections
- Rubber inner insulation
- Tail rubber insulation tends to disintegrate, and muck accumulates on cable ends causing leakage
- Vulcanised India Rubber insulated cable.
- Along with imperial T&E, one of the most common historic wiring cables still in use
- Comes in 2 forms:
- Twisted pair, cotton/rubber insulated, with no outer sheath
- singles drawn into conduit
- Most VIR wiring doesn’t include an earth wire, which is sometimes run as a separate uninsulated single.
- Rated to 60°C
- Rubber insulation perishes, cracks & falls off
- Properties with VIR cable are usually in urgent need of rewiring, and may represent a significant safety risk. However some of the Jute / Hessian reinforced rubber cables that are often seen on consumer unit incomers are still often relatively safe.
- replace it as soon as possible
- don’t move it at all, even small movement sometimes causes shorts.
- Tough Rubber Sheath
- Rubber insulated conductors with a rubber outer sheath
- Cab Tyre Sheathed
- Tinned copper conductors, each core insulated with VIR, & cab tyre outer sheath
- Single, Flat Twin and Flat Triple
- Cab tyre was the same rubber formula used for car tyres, making this cable a very tough rubber cable
- Cheaper alternative to copper
- Used from 1950s to 1970s, and old stock sometimes used into the 1980s. The main periods of use were 1950s and early 1970s.
- The main problem with ali cable is its thermal expansion coefficient. Repeated temperature cycling causes it to come loose at connection points, and it then oxidises, and aluminium oxide is an insulator. Bad connections generate excessive heat and fire can break out.
- The insulation & sheathing is mostly the same as T&E – PVC for decades, may be rubber on older cable.
- A known fire risk
- Aluminium cable creeps, oxidises & fractures, all of which can cause fires.
- Requires special connections, do not connect to old ali cable using connectors intended for copper.
- Al requires a larger conductor size than Cu for the same current rating
- Presence of aluminium cable may be considered a material fact for insurance.
Copper Clad Aluminium
- Each conductor has an aluminium core surrounded by copper
- An attempt to improve the properties of ali cable
- Significantly better than al, the surface oxidation problem is eliminated, creep reduced & the risk from cracking more or less eliminated
- PolyButyl Jute insulated cable
- Red-brown woven appearance
- Once commonly used for mains incomer insulation
- Lots of old PBJ is still safely in service
- Can harden & crack where bent
- Ashathene T&E
- Polythene sheath, precursor to PVC T&E
- Lasts well
- PVC outer VIR inner
- an early T&E cable
- where the inner rubber has failed, the tails can be sleeved
- 2 core Twin
- no earth, used for lighting circuits, or power circuits with a separate (usually uninsulated) single run alongside to provide an earth conductor.
Single insulated PVC
Red, White, Yellow & Red, White, Blue cores