Why is my wire insulation crumbling and what should I do?

What Does Crumbling Wire Insulation Mean? If you've noticed the plastic or rubber coating on your wires is flaking, cracking, or turning to dust, your wiring has reached the end of its safe service life. This is one of the most serious electrical faults a UK home can have. Why does insulation crumble? Age: Rubber-insulated wiring used before the 1960s has a lifespan of around 25–40 years. Many UK homes still have it hidden in walls and under floors. Heat damage: Overloaded circuits, proximity to hot pipes, or poor ventilation cause insulation to harden and crack over time. PVC degradation: Even modern PVC cables can become brittle if exposed to UV light, chemicals, or extreme temperatures. Rodent damage: Mice and rats chew through insulation, especially in lofts and underfloor voids. Moisture ingress: Damp environments accelerate insulation breakdown, particularly in older properties. What are the risks? Exposed conductors can cause: Electric shock if touched Electrical fires from arcing between conductors or to earthed metalwork Failure of RCD protection if insulation resistance has dropped What should you check — safely? Do not pull at cables or remove any covers Look in accessible locations like the loft, under the stairs, or behind loose socket faceplates Check whether your property has old black rubber cables or lead-sheathed wiring — both are well past safe life Check when your property was last rewired or had an EICR (Electrical Installation Condition Report) When to call an electrician: Immediately, if you can see crumbling or bare conductors anywhere If your property is more than 25–30 years old and has never been rewired Before buying or renting out a property with older wiring If a previous EICR has flagged C1 or C2 codes A qualified electrician will carry out a full inspection, issue an EICR, and advise whether a partial or full rewire is needed. Do not use the affected circuits until the problem is resolved.