If your home was built in roughly the first half of last century and has never been fully rewired, there's a real chance some circuits still run on VIR cable — vulcanised Indian rubber insulated wiring. It was the standard of its day. The problem is that rubber insulation doesn't last forever, and much of what remains in Sydney's older housing stock is now brittle, cracked or crumbling.
What VIR Cable Is and Why It Fails
VIR cable is a copper conductor insulated in vulcanised rubber, usually with a cotton braid over the top, often run inside metal conduit or on ceramic cleats. Rubber hardens and perishes with age and heat — and wiring runs through the hottest parts of a house: roof spaces, wall cavities, behind switchboards.
Perished insulation cracks and flakes off, especially wherever the cable is moved or disturbed. What's left is effectively bare copper — sometimes inside a metal conduit that can itself become live if a conductor touches it.
The Hazards: Shock and Fire
Exposed conductors in a roof space are a serious shock hazard for anyone who goes up there — tradespeople installing insulation, antennas, downlights or NBN gear, or a homeowner storing boxes. This is exactly the situation where a missing safety switch turns a hazard into a tragedy, because most homes old enough to have VIR wiring also predate mandatory RCD protection.
The fire risk is just as real: cracked insulation between two conductors, or between a conductor and earthed metal, allows tracking and arcing — localised sparking that can smoulder in dust and timber long before anything trips. Old rubber-insulated circuits were also never sized for modern loads, which compounds the heat problem.
How to Tell If Your Home Has It
Age is the first clue — homes from before the 1950s–60s that haven't been rewired are the prime candidates. Visual clues include cotton-braided cable in the roof space, ceramic fuse holders on the switchboard, and wiring run on ceramic cleats or in old metal conduit.
Don't go hunting for it yourself, and don't handle suspect cable — disturbing perished insulation is precisely what exposes the conductor. A licensed electrician can confirm what you have during an inspection, and insulation resistance testing shows how far gone it is. Not sure if an inspection is worth booking? The wiring age checker gives you a 60-second read based on your home's age, switchboard and symptoms — and our guide on what happens during an electrical inspection explains the process.
What to Do About It
Where VIR is found, the fix is replacement of the affected circuits — modern insulation, properly rated for today's loads, protected by safety switches. Internal rewiring is work for a licensed electrician; where the old wiring extends to the consumer mains or involves the network connection or metering, a Level 2 ASP is required for that part. Either way, it usually makes sense to deal with the board, mains and worst circuits as one job rather than piecemeal.
For the switchboard, consumer mains and network side, call Sydney Power Group on 0466 125 125 or get a quote.
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