I have questions based on my understanding of the 3 wire, single phase, home electrical system (USA). My questions are not about the equipment ground (green or bare) wire, although I realize they are bonded together at the utility pole transformer center tap point and the house Mains Panel.
My understanding (please bear with me):
Electrical power to the house Mains Panel comes from the secondary of the utility company transformer in the form of 3 wires: 2 phase (hot wires) and 1 neutral return wire (center tapped on the secondary and grounded). Inside the house Mains Panel the 2 separate phase wires are connected to the 2 separate hot buses and the neutral return wire is connected to the Mains Panel neutral bus. At the house Mains Panel this neutral bus is also bonded to the ground bus.
In the house Mains Panel the branch circuit hot wires are connected to the buses through circuit breakers and the branch circuit return neutral wires are connected to the neutral bus. Within the house Mains Panel branch circuits the current flow alternates from phase to phase for 240v and from phase to phase through the neutral bus for 120v. If the phase to phase current flow is balanced then virtually no current flows back to the transformer on the utility neutral return wire. If there is an unbalanced current flow, then, only this unbalanced current flows back to the transformer.
My questions:
1. Does this mean the return current from the house Mains Panel neutral bus to the utility transformer flows only in one direction, from the house Mains Panel to the utility pole transformer, and does not alternate (on the neutral return wire) as the current in the phase wires does?
2. If it is a one way flow, then, is this unbalanced current returned to ground at the transformer center tap ground point or is it somehow reintroduced into the phase wiring?
3. If the return current to the utility pole transformer return neutral wire alternates, what keeps it from impeding the current flow of one of the phase wires? If the return current alternates, it seems like it would be "out of phase" with one of the 2 phase wire? If you have made it this far, thank you for your patience.
Thank you,
Mike
My understanding (please bear with me):
Electrical power to the house Mains Panel comes from the secondary of the utility company transformer in the form of 3 wires: 2 phase (hot wires) and 1 neutral return wire (center tapped on the secondary and grounded). Inside the house Mains Panel the 2 separate phase wires are connected to the 2 separate hot buses and the neutral return wire is connected to the Mains Panel neutral bus. At the house Mains Panel this neutral bus is also bonded to the ground bus.
In the house Mains Panel the branch circuit hot wires are connected to the buses through circuit breakers and the branch circuit return neutral wires are connected to the neutral bus. Within the house Mains Panel branch circuits the current flow alternates from phase to phase for 240v and from phase to phase through the neutral bus for 120v. If the phase to phase current flow is balanced then virtually no current flows back to the transformer on the utility neutral return wire. If there is an unbalanced current flow, then, only this unbalanced current flows back to the transformer.
My questions:
1. Does this mean the return current from the house Mains Panel neutral bus to the utility transformer flows only in one direction, from the house Mains Panel to the utility pole transformer, and does not alternate (on the neutral return wire) as the current in the phase wires does?
2. If it is a one way flow, then, is this unbalanced current returned to ground at the transformer center tap ground point or is it somehow reintroduced into the phase wiring?
3. If the return current to the utility pole transformer return neutral wire alternates, what keeps it from impeding the current flow of one of the phase wires? If the return current alternates, it seems like it would be "out of phase" with one of the 2 phase wire? If you have made it this far, thank you for your patience.
Thank you,
Mike