Live and neutral wires
How the mains reaches a home.
Wires to a home
Two wires bring electric power to a home from a pole or from an underground cable. One has red insulation and the other has black insulation.
What do you think the two colours tell us?
What this lesson covers
The idea
Homes receive power from the mains through a live wire (red insulation) and a neutral wire (black insulation) with a potential difference of 220 V between them, passing through a main fuse, meter and main switch to the line wires.
Wires to a home
Two wires bring electric power to a home from a pole or from an underground cable. One has red insulation and the other has black insulation.
What do you think the two colours tell us?
- They tell the two wires apart: live and neutral
- They tell how thick the wires are
- They tell the voltage of each wire
Follow the supply
Press Next step to follow the supply from the pole into the house. This is a picture to read. Home wiring is not for students to touch.
Two wires and a path
The wire usually with red insulation is the live wire. The wire with black insulation is the neutral wire. The potential difference between them is 220 V. Before the wires reach the line wires in the house, they go through a main fuse, the meter and the main switch.
Homes receive power from the mains through a live wire (red insulation) and a neutral wire (black insulation) with a potential difference of 220 V between them, passing through a main fuse, meter and main switch to the line wires.
Notes
The mains has a live wire (red) and a neutral wire (black) with 220 V between them. They pass a main fuse, meter and main switch to the house's line wires.
Check yourself
In the supply to our homes, the wire usually with red insulation is the…
In our country the potential difference between the live wire and the neutral wire is…
The two supply wires reach the line wires of the house through…
The wire with black insulation in the mains supply is called the…
- neutral wire. The neutral wire has black insulation.
- live wire — correct. Yes!
- earth wire. The earth wire has insulation of green colour.
- 22 V. In our country the potential difference between the live wire and the neutral wire is 220 V, not 22 V.
- 2200 V. In our country the potential difference between the two wires is 220 V, not 2200 V.
- 220 V — correct. Yes!
- the main fuse, then the electricity meter, then the main switch — correct. Yes!
- the main switch, then the electricity meter, then the main fuse. The wires pass into the meter through the main fuse. Then, through the main switch, they connect to the line wires.
- the electricity meter, then the main fuse, then the main switch. The wires pass into the electricity meter through a main fuse, so the main fuse comes first.
- live wire. The live wire is the one usually with red insulation.
- neutral wire — correct. Yes!
- earth wire. The earth wire has green insulation. The black wire is the neutral wire.