Notes for part-time electricians

Common sense about safe use of electricity

(1) Safe use of electricity

(1) Consider the endurance capacity of the electric energy meter and low-voltage lines. The electric power that an electric energy meter can withstand is approximately the value of voltage multiplied by current. The voltage of civilian electricity is 220 volts, and the current of 1KW is about 5A. For example, if a 5 (10) amp electric energy meter is installed at home, the rated power that it can withstand for a long time is It is 1KW, and the power that can pass through in a short time is 2KW.

(2) It is necessary to consider how many electrical appliances are allowed to be plugged into one socket. Use sockets with more than three pairs of jacks, and you cannot use high-power appliances such as air conditioners, rice cookers, rice cookers, and electric water heaters at the same time. Even if the power of the socket is sufficient, you should try to avoid it. On the one hand, the lead-in wire of the socket is relatively small, and at the same time, the socket plug is in contact. If the current is too large, it will heat up and burn out

(3) Do not place oil, cotton, or cotton near low-voltage lines, switches, sockets, and fuses. Sawdust, wood and other easily stainable items.

(4) Before an electrical fire, there is a precursor that should be paid special attention to. That is, the wire insulation will first burn due to overheating, emitting an unpleasant smell of burning rubber and burning plastic. Therefore, when you smell this smell, you should first think that it may be caused by electrical reasons. If no other reasons can be found, you should immediately turn off the power and shut off the power until the cause is found out and properly dealt with before closing the power supply.

(5) When installing electrical equipment, the quality must be guaranteed and all safety and fire protection requirements must be met. Qualified electrical equipment must be used. Damaged switches, lamp holders and damaged wires cannot be used. The joints of wires must be firmly connected according to the prescribed connection method and wrapped with insulating tape. Tighten the screws on the wiring pile heads and terminals to prevent poor contact due to loose wiring.

(6) After the electrician installs the equipment, it does not mean that it can be done once and for all. During use, if the user finds that the lamp holder and socket wiring are loose (especially the plug wiring of mobile electrical appliances is easy to loosen), the contact is poor. If there is overheating, please call an electrician to handle it in time.

(2) Safe use of electricity

(1) Do not buy fake and shoddy household products with the "three noes".

(2) When using home appliances, there should be a complete and reliable power cord plug. Household appliances with metal casings must be grounded for protection.

(3) Switches and fuses cannot be installed on the ground wire and neutral wire. It is prohibited to connect the ground wire to tap water or gas pipes.

(4) Do not touch live equipment with wet hands, and do not wipe live equipment with wet cloth.

(5) Do not connect wires indiscriminately and do not move live equipment casually.

(6) When inspecting and repairing household appliances, the power supply must be disconnected first.

(7) When the power cord of a household appliance is damaged, it must be replaced immediately or wrapped with insulating cloth.

(8) When a fire occurs in household appliances or wires, the power supply should be disconnected before putting out the fire.

(9) It is forbidden to use copper wire instead of fuse, and it is forbidden to use rubber glue instead of electrical insulation tape.

(10) Install an electric shock protector in the circuit and check its sensitivity regularly.

(11) When there is a thunderstorm, do not use radios, video recorders, and televisions, and unplug the power plugs and TV antenna plugs. Don't use the phone temporarily. If you must use it, use the hands-free function.

(12) It is strictly forbidden to connect electric wires without permission, and students are prohibited from using electric stoves, "heaters" and other electrical appliances in the dormitory.

(13) Do not fly kites or play ball games under cables or wires.

(14) Do not approach high-voltage charged objects (outdoor high-voltage lines, next to transformers), and do not touch low-voltage charged objects.

(3) Unqualified plugs cannot be used

The plug form specified by my country's national standards is flat, with two poles and two poles with grounding (commonly known as three pole) plugs.

Some plugs that have appeared in the past have been judged as substandard products or eliminated products.

1. Cylindrical plugs are substandard products that have been eliminated;

2. Plugs with holes on the pins have insufficient bearing capacity and are dangerous products;

3. Plugs with rotatable pins do not meet the standard requirement of "locking" and are dangerous;

4. Plugs with hidden ground pins are dangerous products that are not allowed to be produced according to national standards.

5. The ground pin of the three-pole plug is the same length as the other two pins and cannot be protected by grounding, which is dangerous.

(4) Inferior sockets cannot be used

Characteristics of inferior sockets

1. Rough workmanship, appearance, jacks, and contact copper sheets have burrs and are not smooth .

2. The contact copper sheet is thin and has no elasticity. The plug feels weak when inserted, cannot be inserted tightly, the power is cut off if there is a slight vibration, and the plug even comes out as soon as the hand is loosened.

3. Looking from the jack, the position of the contact copper plate is not facing the jack. Some grounding jacks do not have copper contacts inside.

4. The insulating shell is thin and light, has poor mechanical strength, is fragile, and is light in weight.

5. If there is a protective door, it can be opened with a single plug. After plugging in, the grip is poor, the contact is often not good, and the plugging and pulling out are seriously jammed.

6. Cheap price.

(5) The copper parts of the socket can measure the quality of the switch socket

The copper parts in the switch socket are one of the key factors to ensure smooth current and reduce heat generation. In terms of performance, copper parts should meet the standards of oxidation resistance, strong toughness, thick copper sheets, and less riveting.

1. The thickness of the copper sheet reduces the resistance of the copper piece itself;

2. It has strong toughness, especially when used in the socket part, ensuring that the socket can be used for a long time without loosening;

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3. Anti-oxidation, non-rusting, reducing resistance and heat caused by corrosion;

4. Less riveting, preferably one piece of copper as a whole, to further reduce breakage of the riveted part and rivets Fever condition.

(6) The significance of the socket protection door

A large number of ordinary indoor sockets in households are generally installed at a position 300mm to 400mm above the ground along the lower edge, and this position is the most accessible to children. Children are often very curious about novel things in places that are easy to reach. For indoor sockets that are within easy reach, they may poke the sockets with fingers or other hard objects. Protective doors can greatly reduce the risk, so families must Install sockets with protective doors. For a qualified socket with a protective door, the two-hole socket must be inserted into both holes at the same time and a certain amount of force can be used to open it. The three-hole socket must be inserted into the top ground wire hole first, and then the neutral phase wire hole can be opened.

(7) Wiring method of sockets and plugs

For household electricity, standard single-phase users have three wires, phase wire L, neutral wire N and ground wire PE, neutral wire N The line and phase wire L have the same cross-section, and the ground wire PE is 2.5 square millimeters and double-colored. The protection of household electricity is completed by the wiring of socket plugs. The wiring principle of plugs and sockets is: left zero and right phase are grounded. That is, the neutral wire N is connected to the left jack of the socket, the phase wire L is connected to the right jack of the socket, and the ground wire PE is connected to the upper jack of the socket. The metal casing of the home appliance is connected to the top of the plug. When the plug of the home appliance is inserted into the socket, the casing of the home appliance and the grounding wire PE can be reliably connected to achieve safe protection of household electricity.