what can happen if you reverse two phases.

[ajb]

We had TWO-phase power (and still do to a very limited degree) when we were flooded last year. Doing the post-flood walk-through with the electricians I mentioned this to them and they looked at me like I had 3 eyes (hasn't even been in the NEC in years). Crazy buildings from 1928...

Two phase? How did that work? Presuming you mean two proper phases and not split single phase (I'd guess from your signature that you know the difference!).

 

[Chris15]

We had TWO-phase power (and still do to a very limited degree) when we were flooded last year. Doing the post-flood walk-through with the electricians I mentioned this to them and they looked at me like I had 3 eyes (hasn't even been in the NEC in years). Crazy buildings from 1928...

REAL two phase or just two thirds of a three phase supply?

 

[tjrobb]

Two phase, 180d separate. Was the 5-wire style (2h, 2n, g). I'd have to look at the motors for more specifics. Probably was installed due to the needs of incandescent lighting in the '20's.