I have read of very large apartment buildings having 120/208 services to apartments. I have also seen a single-family residence with 480 and a transformer in the garage. "Re-zoning" a commercial building into a residential one in my area basically consists of saying, often to yourself, "I live here now." I used to live in a renovated carpet factory. No 3-phase there, but, as it was originally a non-residential building, it could have been.

A 120 V circuit is safer than a 240V one. The main advantage of 240v over 120v is that it requires only half as much current to deliver the same watts into a resistive load, therefore, the wire can be smaller. In the US, single phase residential voltage comes from a center tapped transformer. The center of the winding is the neutral while the two outer ends are the two voltages supplied to the distribution box (circuit breaker or fuse box). Both 'hot' lines measure 120v with respect to the neutral, but since these two hot lines are opposed by 180 deg, they measure 240v with respect to each other. With this system, 240 power can be supplied with lines that are at only 120v with respect to the neutral. Now for the big surprise about ac motors. For motors larger than a few horsepower, the current does not vary lineraly with the load! As the shaft load increases, the current does increase some, however, the big change is the phase angle between the voltage and current. Power delivered is voltage x current x power-factor. When the current is 90 deg to the voltage, power is zero; When the current is in phase with the voltage (0 deg), power factor is 100%. So it is possible to have considerable motor current in the wires with little power output. Fractional horsepower motors have a goodly amount of resistance compared to their reactive component and because of this have greater resistive losses. The debate between 50 and 60 hz can go on forever and from a practical sense, has existed since the dawn of electric power. 60 hz has an advantage over 50 hz in that the cross section of the iron in a transformer can be a little smaller for delivering the same power. Hysteresis losses in magnetic materials is a positive function of frequency, thereby increases with frequency. But, at the same time, the peak magnetic flux required to transmit the same power increases with decreasing frequency. Aircraft systems uses 400 hz to reduce weight. Europe tends to use 50 hz while the US and Canada uses 60 hz. Sometimes it seems that this difference is maintained to make it more difficult to apply products from one side of the ocean to the other - e.g., trade protectionism.

I have installed (as a DIY'er, in my home) several floor heating systems. Warmly Yours, and Warmwire. I believe that they are all quality, and will perform well, if properly installed. Who knows - all this cable could come out of the same factory in China? "Does it have a two for one wiring system?" What is that? If you trust your installer, and he has had success with Flextherm. then I'd go with his advice. It's all going to cost about the same with labor, thermostat, electrical circuit. There are procedures when installing the cable - taking ohm readings, at different phases of the installation. All the cables should last a long time. My Warmly Yours is 10 years old.

Excellent info! Main takeaway: 240 gets concurrent elements which can lead to faster results. This makes perfect sense. I didn’t learn that from any other conversation and a couple of you commented about this. Also, 240 cannot go be below a counter. I’m good with this. I wanted it to be counter high but not on a counter’ which I don’t think you could do anyway. There are 27” built-ins and 30” built-ins. They have the same interior space, but the 27” does not come in 240. Becky- I am also a little shorter and am slight concerned not having the traditional microwave opening, but a traditional oven pull. I’ll learn! Thank you everyone and I am staying with the 30” built in 240. Regular oven height and I’ll have 3 nice drawers below and typical above oven storage up top. For my plans, this is going to be great! I think the advantium will be my primary everyday, everything oven. I am also planning on a dual fuel range with two ovens. I’m getting the cafe modern glass version. It’s a very sleek look. Very excited. Thanks again and I hope this helps others, too. Although I’m having to pay to install the 240 circuit, I think in the end I’ll be happy I did. Looking forward to 3 ovens. If I find a neighbor with a 120, maybe we’ll have an Oven-off and I’ll report back to this thread!