Around 670 construction workers downed tools unofficially at Runcorn Thermal Power Station on Friday of last week.
They forced the £65 million project to a complete stop.
Workers say they face bullying and intimidation over working practices.
They are members of the Unite and GMB unions.
They last walked out in January over “disgusting” conditions in the kitchens and toilets. They were paid £250 to return to work. But one worker last week said “this time we are sticking to our guns”.