In house wiring can the white wire have some current too?

Answer 1

Yes. The white wire (the "neutral") is the "return" for the hot. Recall that electric current had to "get to where it is used" and then has to "get back" to the outlet. (A complete circuit is necessary.) You need the black wire (the "hot" wire) to carry the current out and the white wire to carry the current back, and the currents should be equal. You don't want any current returning on the ground wire or "leaking to ground" from anywhere in the circuit. Another way to look at this is that the black and white wires form "rails" for the voltage. Anything hooked up is connected "across" the rails. It's connected from the black to the white - from one rail to the other. All the appliances in the house are connected in parallel across the black and white, or in parallel across those voltage rails. (That's why all appliances operate on the same voltage and why if one fails, it doesn't affect any of the others.)

Answer 2

No it is not a standard practice. That said you will find such a connection from a light fixture junction box, that has the supply source in it, down to a a light switch junction box. The neutral for the light is already at the light junction box but the switched leg has to go down to the switch. The black "hot" wire is connected to the white wire in the cable going to the switch and from the switch it returns in the black wire in the same cable which is then connected to the light fixture.

Answer 3

Yes, the white wire in house wiring is typically used as the neutral wire and is part of a circuit where current flows to return to the electrical panel. Therefore, it can carry some current, but ideally it should not have current under normal operating conditions as it is intended to be a return path for the current.

Answer 4

White is neutral. Black (and red, if you're looking at a 240v circuit) are hot.

Answer 5

black is hot (live), white is neutral, or common