Is split phase the same as single phase?

Are they the same? Meaning they can have 1 or 2 hots and a neutral.

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• reme_1
Lv 7
7 months ago

what the heck are you talking about? THis is a gay question section.

• iammclane
Lv 7
7 months agoReport

I think the asker just didn't know how to categorize his question, so the algorithm picked out a couple words and placed it in LGBT for him.  I can't imagine which words, though.

• 7 months ago

Split phase IS single phase.  3-phase transmission delivers the same waveform over three conductors, with the waveform on one conductor being 120 degrees behind the waveform on the second conductor, and 120 degrees AHEAD of the waveform on the third conductor.  In commercial power transmission, there is a neutral with respect to all three of those conductors, but it is grounded to Earth for high tension lines, so you don't see it on the transmission towers or at the high voltage, 3-phase distribution level on utility poles.  (On portable power generators and on most electrified railways, you'll see a fourth conductor for "neutral" and a fifth one for "ground".)

Typically, a stepdown transformer on a residential utility pole drops the voltage from ONLY ONE of those three high-voltage conductors at the top of the pole, so it is a single phase supply to the lower (household) level on the pole.  The transformer is wound with two equal, (120 volt in the USA) secondary legs off a center tap.  The tap is considered neutral, and is connected to the center of three household-level conductors, which are typically mounted so there are three parallel, equally-spaced wires from one utility pole to the next, just above the communications cables.  This center tap is also grounded to Earth at the bottom of the pole.  The equal windings on the two legs of the secondary deliver a single sine wave to the two hot leads (the top and bottom wires, respectively), with each of them having an identical but opposite voltage with respect to the middle, neutral wire.  This provides the appearance of the transformer having somehow shifted the phase by 180 degrees between the two hots, which is why it has the name "split phase". In reality, there is no phase shift at all.  The two hots reach their maximum voltage wrt neutral at exactly the same moment, so technically it is "single phase, three-wire" service.

The end result is that regular household voltage is available from either of the two hots to the neutral, but TWICE the regular household voltage is available from one hot to the OTHER HOT, for running certain equipment like electric stoves, clothes dryers, heat pump compressors and the like.  However, it's still all single phase.

In a household installation, you'll typically see a twin-bank circuit breaker panel with both of the two hot leads connected to outboard buses, and the neutral on the center bus.  You can use either of the hots for any standard circuit in the house.  They are interchangeable.  Any imbalance in load between the two sides will be countered by current in the neutral (which isn't a problem in household installations).

Hope this helps.