Quote Originally Posted by Dan View Post
If you are using a neutral, I wonder if you are looking at a 120 volt application. In the US, the neutral provides us a 120 volt power supply which is used for all household receptacle and lighting (low amperage, single phase loads) A delta electrical supply will always have a "high" leg, where the potential to neutral is close to 200 Volts. By the way, again, in the US, a 240 power supply (less common) is the result of a delta transformer, and a 208 power supply (more common) is the result of a Y or star transformer. We occasionally find 120 volt components burning out on new installations because the "high" leg is used. I am really weak on this. Let me find a web page for you to refer to.

http://polk-burnett.apogee.net/pd/dsaud.asp

One should never become too old to relearn things.
Very interesting Dan, but I'm confused as to where you would use the 208 volt supply?

I can appreciate that the 120v (110V in the UK) is used for safety purposes, and the 240V supply is used in the US for equipment that would draw excessive current on 120V, I also understand 3 phase very well.

I'm at a loss as to why you would also need 208V?