Union workers wreaking havoc on commercial property developments in western Sydney appear to be sparing projects backed by industry super fund Cbus from their disruptive industrial action.

Since February, about 750 Electrical Trades Union members at poles and wires company Endeavour Energy have refused to show up at appointments to switch off powerlines on construction sites – causing months of delays and adding extra cost to thousands of homes and warehouses that have an end value worth billions of dollars – in a bid to get a 24 per cent pay rise.