Basic knowledge of switch socket and electrician
1. Classification of electricity use:
(1) Household: Single phase, 220V~
(2) Industrial use: 3-phase, 380V~
(1) Household electricity
Household electricity refers to the 220 volt electricity we often say, also called single-phase electricity. There are two wires, one live wire and one neutral wire. The live wires connect the load such as light bulbs and other electrical appliances, then connect the neutral wire to forms a loop. Then electrical appliances can work normally. The neutral wire here is also grounded in the power plant. In the single-phase lighting circuit, in some places, yellow means live wire, blue is neutral wire, yellow-green is ground wires. Some places, red means live wire, black means neutral wire, yellow-green is the ground wire. Generally, red is the live wire, blue is the neutral wire, and black is the ground wire.
Single-phase distribution box (general distribution box)
(2) Industrial electricity
Industrial electricity is commonly referred to 380 volts electricity, which is mostly used in factories. This type of electricity is mostly three-phase four-wire. In the four wires, there are three live wires and one neutral wire. The live wire refers to any phase in the three-phase four-wire power grid ABC , The neutral wire refers to the wire that has no voltage and has current to the ground in the three-phase four-wire. Three live wires connect the load such as Electric motor and other electrical appliances, then connect the neutral wire to forms a loop. Then electrical appliances can work normally. The neutral wire is grounded at the power plant.
Three-phase four-wire power box
(V16 series MCB three-phase 12 way distribution box E type)
2. Commonly used electrician symbols
|power（P）||W||live wire (phase wire)||L||neutral wire||N|
|Splash-proof grade||IPXX||ground wire||E||Alternating current||~|
|Fluorescent lamp current||AX||“off” position||O||“on”position||—|
3. Basic knowledge of switch & socket
Installation method classification
The installation methods are: surface mounted and flush mounted. In simple terms, the surface-mounted type is installed on the outside of the wall with its own bottom box, and the flush mounted type is installed on the bottom box buried in the wall. Most of the switch & socket on the market are flush mounted type, and surface-mounted switches are only used in some counties, townships, and rural areas. There are also many flush mounted switches that are installed with surface-mounted bottom boxes.