Allocating lines from my 3P breaker

[GM489]

I have a 480V 3P-Y breakerbox at my facility capable of 225 A. Most of them are 3 breakers with 1 switch for all three (running 2 industrial ac units and 2-208V transformers, 36 A incoming).

One set of three breakers has three switches, one per breaker. The labels indicate that only the first two are being used to power lighting in the facility. The third has no label but is switched on.

Is it possible for the lighting in our facility to be powered by two out of three phases? If so, is it more likely that each is being used as a 277V 1P? What are some ways I can check this?

If the third breaker is unused, would it be treated as 480V or 277V? Can individual legs be tapped as 1P, and if so, can I pull a much larger amperage from one vs the other two?

My office requires one outlet of 240V, 30A. If possible to tap the aforementioned leg, and step it down to the needed condition? My alternative is to sacrifice 3 of my 208 outlets and step them up.

Thanks

 

[ActionDave]

You left out the option of hiring a qualified electrician, which is what you need to do.

 

[tom baker]

Especially for 480. From a fire and shock hazard, its far more dangerous than 120.

 

[Jraef]

A single pole breaker from a 480V Wye system would be 277V, line to neutral. If you want to step up to 240V, you are better off using a 2 pole breaker and going with a standard 480-240V single phase transformer. Your electrician will know what to do.

 

[Jraef]

That said...
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