Coleman Fresh N Vac Blows 24 V Transformer.

[JGinther]

The 208v center leg was used for high power lighting.

Actually, there is no purpose of this voltage, it just happens to measure out at that. Don't try to use it as it is only for phase to phase loads. I don't think you can even find a single pole breaker for 200+ volts. One reason it is there is because it is a byproduct of a delta transformer which gives you a little more voltage for motors, while still enabling 120V loads (there are many others that have more to do with the power company and emf reduction). Although it measures out at a 'common voltage', it is not a proper signal to neutral for power usage. Just leave them blanked out.

 

[2Biz]

Actually, there is no purpose of this voltage, it just happens to measure out at that.

Not that I would use 208v to power anything...But why are metal halide ballasts rated for 120\208\240\277v ?

My intent is not to lead anyone astray! I did a lot of studying on this when I had to change out a 5hp 3 phase motor in the beginning. The readings I was getting between phases and from each phase to common didn't make sense. I'm glad I did the research... 3-1/2 years later the motor is still running. I must have wired it right!

 

[MEP001]

Not that I would use 208v to power anything...But why are metal halide ballasts rated for 120\208\240\277v ?

We're running a Vector which requires 208V 3-phase. There's no high leg (They all read 120V to ground), and running anything off two legs single-phase gives 208V instead of 240. I'd have to tap the lights at 208V to run them on a 2-pole breaker.

 

[JGinther]

Yes, Delta power is 240 pole to pole. Wye is 208 pole to pole. The lighting tap described is for people with wye configured secondaries, and would only be hooked up pole to pole (double pole breaker)