[retiredsparktech]

sorry I wasn't clear about the 277, it comes from the service, and powers all the lighting, so I think that the transformer will provide the 240 volts line to neutral. I have used the 240 volts line to line and yes it works just fine, but it does not simulate the conditions in other countries,and most of them use 240-220 line to neutral . I am currently using a step up transformer, 120 volts to 240 volts, and some universal power strips. I'm installing wall outlets with different sockets for the most commonly used plugs, and want the correct voltage for them

That's the way, I was going to suggest doing it. If you feel that you need a reference to the neutral, Just designate one leg of the 240 volt winding as a neutral and tie it to ground.