The two wires in the lighting circuit, one is called the fire wire, is the power line in the circuit to deliver electricity; one is called the zero line, is the line from the generator or transformer secondary side neutral (N), and the phase line (L) constitute a circuit, power supply to the electrical equipment.
Usually, the zero line in the secondary side of the transformer neutral (N) and the protective earth (PE) repeated ground (PEN), play a double role in protection
Ground is in the electrical system or electronic equipment, connected to the earth, connected to the shell or connected to the reference potential of zero wire. General electrical appliances, ground wire connected to the shell, in order to prevent electrical appliances due to the destruction of internal insulation shell charged and caused by electric shock
Difference:
1, with the color distinction: in the power cable, yellow, green and red, respectively, on behalf of the A-phase, B-phase, C-phase (three-phase firewire), blue on behalf of the zero line, yellow and green on behalf of the grounding line.
2, with the electric pen to distinguish: the fire wire with electric pen test neon tube will glow, while the zero line will not.
3, with a voltmeter to distinguish: the voltage between the different phase lines (i.e., the fire wire) for the line voltage of 380V, the phase voltage between the phase line (fire wire) and the zero line (or a good grounding body) for the phase voltage of 220V, the zero line and a good grounding body for the voltage of 0V.
Precautions in the connection of power
I. To prevent electrocution and short-circuiting;
Two, be Attention to the switch control line;
three, the zero line is best not to connect a fuse;
four, the center of the lamp base to the fire wire;
five, ground line and zero line do not mix;
four, the appliances disconnected from the fire wire so that touching the appliances will not be electrocuted, if disconnected from the zero line, the people will be electrocuted touching the appliances.