u/Brilliant-Hurry9162

So, getting my house's (1950s QLDer) ceiling cavity wiring cleaned up ready for insulation, making sure everything is supported between joists, has mechanical protection etc.

Part of this is rewiring some portions. There was some old rubber insulated cable etc in there that has been removed. The sparkies have stated that the grey coloured TPS that is throughout the cieling cavity fine to leave in place/use because it still meets standard and is in good condition (still flexible no green goo etc.). Having looked at some offcuts it's solid core with either no earth or a bare earth between the hot and neutral.

Is this correct or should I just say go nuts and replace everything?

Thanks in advance

Pic attached for reference.