No matter which socket, there is only one correct connection, and the other combination is wrong.In order to ensure equipment and personal safety, the socket must be inspected according to the specification before it is put into use.Accurate identification of various wiring errors requires necessary tools and methods.
1. Identify "zero/ground reverse"
TN and TN - S - C - S distribution system, the zero line (N) and protective earth (PE) only 1 point connection, in addition is strictly separate (part), both of zero potential, the difference is that: in the single-phase system zero load equal load current with the phase line;Unless there is a leakage of electricity, normally the protection of the ground wire is not charged.
1.1 the hazard of "zero/ground reverse".
If a zero/socket in single-phase circuit to meet the, ground is to provide the load current circuit protection equipment can still run, but is the result of other load series with zero current will be in the form of jamming signal equipment, fault protection earthed disable filter, especially bad for sensitive electronic equipment.The obvious communication noise of hi-fi is typical of this wiring error.
Because the protection ground wire only has the potential connection effect, does not carry the power, so the line diameter may be more than zero line.When carrying a large load current, it will have a larger line pressure drop than the zero line, and it will become a fire hazard.
1.2 identify "zero/ground reverse"
Distribution circuit under no-load condition, ground zero and protection of electrical properties not any difference, cannot identify single measurement from the socket, only access load on a line current is measured by difference to judge right and wrong.
The "leakage protector (or residual current protector RCD)" on the line can also effectively prevent such errors.After the load is connected to the "zero/ground reverse" socket, the protection device can detect the difference between the zero line and the phase line current, and trigger the protection to power the circuit.
2. Check the "bad connection" through the socket
The purpose of the power socket is to provide power supply to the electrical equipment in a safe, reliable and convenient way, and the outlet must meet the voltage output standard."GB50052 power supply and distribution system design specification" 4.0.4 stipulates that "under normal operating conditions, the voltage allowable value of the terminal of the power equipment" is between +5% ~ -10%, and generally is +5%;"JGJ/T 16-92 civil building electrical design specification" 3.3.3 has similar provisions.
For the reasons of external power supply, the undervoltage of power supply is mainly caused by the improper selection of line, high resistance point or line path.Check the wiring quality of the socket itself.It is a simple and feasible way to measure the voltage drop of the line through the wall outlet and determine the fault of the line.
Measuring voltage drop must use high power load, which can bring a little trouble to the detection process.In theory, testers can use a large electric stove as a load, but the actual operation is neither safe nor convenient.No, the line was not measured, but the electric stove caused the fire.
5. Although the young and small are not the pen officials, they also want to have the long task-low-voltage ac power supply line special measuring instrument introduction.
For the simple, fast, safe and accurate inspection of wall socket wiring, it is found that common faults in low-voltage ac power supply lines are common.Circuit analyzer.The meter is designed according to the Chinese voltage design of 220V, and all measurements and tests are completed by using the national standard 3-core plug access.