Electrical installations wired prior to 1960 are likely to contain cable insulation known as VIR (vulcanised Indian rubber) or TRS (tough rubber sheathed) which is now coming to the end of its service life.
VIR and TRS cable insulation may have deteriorated to the point of exposing live conductors, so take extra care when accessing roof spaces or performing repairs or renovations in older homes.
Make sure the electrical supply is isolated before you enter the roof space. Isolation is also a good risk control for renovations involving wall alterations which may have live electrical cables in them.
All licensed electricians should be aware of these types of cable and the likelihood of the insulation failing.
When VIR or TRS cable is detected, the homeowner, business owner or the owner of the installation should be told about the risks with the wiring and how to eliminate these risks. It’s likely that the wiring systems will need to be replaced.
If you employ licensed electricians, make sure they can identify these types of older wiring systems before work gets underway.
VIR cable can be seen exiting the metal conduit.
Deteriorated rubber insulation exposing live conductors.
Image courtesy of Department of Mines, Industry Regulation and Safety, WA.