Phases Phasing Me Less
on Dec.23, 2004, under Technology
I had an electrical model contradiction recently… Houses are supplied often with single-phase power… the poles in your neighborhood typically have a hot and a grounded neutral. Coming from your local transformer, you get three wires. I had assumed that you would get a 240, 120, and neutral. However, in my recent dealings with three-phase power, I came to realize that each row of breakers is fed by a different phase, rotating through them. As a result, your three phase breakers use three consecutive rows, obtaining all three phases. Household 240 breakers use two rows… so how does that work? That contradicts the transformer providing 240-to-neutral. Answer: split–phase. Since it’s not phases, but two transformed currents from the same phase, they can be added via series to get your 240. Wow.
