On the Electrical main board at home,there is a rotator selector to choose between 3 lines. The guy who installed it said we could switch the line when power goes down on one and said we have ‘3phase’ power.Could someone explain what this arrangement is,I’m confused by what the guy said.

Question

I don’t necessarily understand how it can be termed 3 ph power,because we don’t simply get 3ph to homes as we please,right? Moreover we don’t have any heavy machinery that might even require it. Could someone explain how this arrangement works? Is it just switching between feeders like in a ring fed arrangement of the power system? Or is it actually 3ph power(?)

In: 4

Answer 1

Power plants generate 3phase power as it is more efficient to generate and transport. It uses a different wire for each phase.

3phase power is running down the street and generally also into houses. 3phase power allows you to connect heavy loads. and a normal houshold only needs a single phase.

The electricity company will hook you up to one of these phases ensuring all 3 phases in the neighbourhood are loaded more or less equaly. (Your neighbour is probably connected to a different phase than you.)

If phases are loaded unequally, a certain phase might become overloaded and the voltage might sag on that phase. The selector switch allows you to easily switch to another phase.
In rare occasions, a single phase might be interupted due to damage. Also in this case you can switch to a different, still working phase.

In cases of feed-in (solar panels) the selector switch allows for injecting electricity into the phase that is in the most need for power.

It is uncommon that this is done manually and in a normal household.