New 120/240 3 phase service or new 120/208 3 phase service

[hillbilly1]

I'm going to be "that guy"...

It's 240/120 3 phase 4 wire, also 208/120 and 480/277. For 3 phase, the higher voltage is always first. That way 240/120 3 phase can't be confused with 120/240 single phase.

May be a mute point, but “three phase” and “single phase” after the voltages kinda indicate the system! So don’t know what the confusion would be! LOL!

 

[synchro]

120/240 delta is simplest and least cost. If you must go with 208/120, still likely best to go with buck/boost on any equipment that won't take 208 so well. Only need minimal sized units and can connect them in open delta so only two needed instead of three per application. connect them so they are only "on" when machine is on and you have no idle losses either.

Another alternative with 208/120 is to use a 3-phase autotransformer such as ACME makes. They label it as 240V primary and 208V secondary, but I assume you can use it in reverse since it would be the "boost" part of "buck-boost":

 

[jim dungar]

I'm going to be "that guy"...

It's 240/120 3 phase 4 wire, also 208/120 and 480/277. For 3 phase, the higher voltage is always first. That way 240/120 3 phase can't be confused with 120/240 single phase.

The ANSI standard is to include a Y when the system has normal line-neutral loads from Wye sources, like 208Y/120 and 480Y/277.

 

[Cartoon1]

Thank you guys, All of the answers have been great!!! much appreciated.