How would you compare 3Phase to single phase? What I'm asking is I had a call from a potential customer to look at some work for him. When I got there he showed me his service. I have heard of 3phase residential but never seen it. It is underground 3Phase delta, goes into a trough in the gararge. From the trough there is a nipple up to a 60amp 3phase combination meter and fuses enclosure. (3 60 amp fuses). From there conduit to a panel in the house. Also out of the trough a nipple up to a single phase meter, then a 100 amp breaker and conduit to another panel in the house. (next to the other one). What the HO wants is 200 amps, either combined in one or upping the 60a to 100. The problems, the POCO here will not let you keep the meter in the garage(or basement or wherever) if you are changing anything. Also being underground I would need them to disconnect and reconnect and the engineer said it wouldn't be the same day (We cut and reconnect ourselves on overhead services.) Anyway my question. I was thinking after looking at it that even though one panel is 60amp it is 3 phase and has that extra leg (although you need to be careful with the high leg) Would you say the 60 amp 3phase is almost equivalent to the 100 amp single phase? He wants to add some 240 lines for his daughter to move in, ie: range,. dryer and other kitchen items.