Ruined rubber insulated wiring

Rubber insulation has a 25 year lifespan. It hasn't been used for over 50 years...

Insulation failure

Failed rubber insulated wiring behind a light switch Crumbled rubber insulation resulting in exposed live wires These pictures show the back of two light switches. The rubber insulation has crumbled to dust, leaving exposed live wires.

There is no earth connection, and the backboxes are metal. If one of those wires contacts the metal box, it will be live, including the screws securing the lightswitch.

Fuses will not blow, but anyone touching the exposed metal parts will get an electric shock.

Attempted repair?

Dangerous bodged repair to crumbled wiring Despite the obvious destroyed condition of these wires, at least one person has attempted a repair using tape and small pieces of PVC insulated flex.

This of course does nothing, as just moving the wire causes more insulation to fall off.

The only slightly good thing is this switch has a plastic box - but this switch is far more recent that the wiring connected to it.

End of life cable

Ruined rubber insulated wiring for a lighting circuit The cable is a twin core type, with rubber insulation and an outer rubber covering. The wire is tinned copper.

This mess dates from the 1940s or early 1950s and should have been replaced decades ago. Prior to these photographs being taken in 2010, all of it was still in use.

It was pure luck which prevented serious injury, death or fire.