A bid to end power workers’ six months of industrial action – which is delaying major government infrastructure projects and thousands of affordable housing developments – has failed, even as work bans spread across Sydney and most of NSW.

The Fair Work Commission on Wednesday dismissed electricity provider Endeavour Energy’s application to terminate the Electrical Trades Union’s bans on switching off power lines – critical for installing electricity infrastructure and performing maintenance – after rejecting the company’s claims that it was threatening the safety of the population.