Ok, I guess I openned a can of worms. Residential 120/240 is derived from a single leg of three phase power. 120/208 is derived from two legs of three phase power. From the pics (Nova's), it seems that the delta could essentially carry 120/208/240, with the 208 from L2 to Grn. The Wye system looks like it won't achieve anything past 208V. So in a residential setting, would the transformer be a Delta? Then if this is the case, you have L1, L3 and Grn coming into the house, where's L2?
Back on page 21 this guy asks this, "single phase to three phase converters", they talk about rotary vs. static phase converters. Are these creating three phases out of the one leg of three phase? and if they are, would it make a different again if it were a wye or a Delta Transformer?
Following the follow-up of 422.60A, I also referred to 422.61 for the listing of the elements, the unit has been modified it seems (30 Amp cord and Plug for what I'm coming up with at 38.46 Amp). I found a wiring diagram on the junction box cover plate. After clean up I can barely make out that it shows Single and Three Phase wiring. All my numbers are lost so I will refer to the manufacturer. Why I was checking is that the newer units and replacement elements come as 208 and 240. Making it work isn't the issue, now it's about phase conversion and why would one system (Wye vs. Delta, 208V vs. 240V) be better than the other and for what structure application. Is it about money and the ease of power distribution? Or is there a valid reason for the difference? Then another explaination please, some of the guys doing the multiplexes were wiring with three phase and there were others wiring with the Single phase. I didn't have the chance to install the cans so I'm wondering now what woild be the difference? If in the three phase units wouldn't be hard to get the 240V for the household appliances? Thanks, if you can.