The circuit breaker is used as a main power protection switch or a branch line protection switch in the home power supply. When a residential line or household appliance is short-circuited or overloaded, it can automatically trip and cut off the power supply, thereby effectively protecting the equipment from damage or preventing accidents from expanding;
Households generally use a two-pole (ie 2P) circuit breaker for total power protection, with a single pole (1P) for branch protection;
If the rated current of the circuit breaker is too small, the circuit breaker is easy to trip frequently, causing unnecessary power failure. If the selection is too large, the expected protection effect will not be achieved. Therefore, the home appliance circuit breaker is correctly selected. important.
Household circuit breakers are generally divided according to the current in the actual circuit of the home, and the rated current is generally between 16A and 63A. Use 1P, 2P, or 1P+N circuit breakers.
The general household circuit breaker has 2P 32A circuit breaker (main switch), 1P 16A circuit breaker (light switch), 1P 20A leakage circuit breaker (five-hole socket switch), 2P 20A leakage circuit breaker (three-hole socket switch).
RCCB refers to residual current operated circuit breakers without overcurrent protection for household or similar purposes where the AC 50Hz, 60Hz or 50Hz/60Hz, rated voltage does not exceed 440V, rated current does not exceed 125A, and the operating function is independent of the power supply voltage. .
RCBO means suitable for AC 50Hz, 60Hz or 50Hz/60Hz, rated voltage not exceeding 440V, rated current not exceeding 125A, rated short-circuit capability not exceeding 25000A, action function independent of power supply voltage or over-current protection for household or similar use Residual current operated circuit breaker.
RCCB and RCBO are simply called RCDs.
The main functions of RCD:
1. Indirect contact protection for people,
2. Provide protection against fire hazards caused by ground fault currents that persist due to inoperating overcurrent protection devices (rated operating current does not exceed 300mA)
3. RCD with rated residual operating current not exceeding 30mA can be used as supplementary protection measure when other electric shock protection measures fail.
The function of the isolating switch is to disconnect the circuit without load current. The device to be repaired has obvious disconnection point from the power source to ensure the safety of the maintenance personnel. The isolation switch has no special arc extinguishing device and cannot cut off the load current and short circuit current. Therefore, the isolation switch must be operated only when the circuit is disconnected from the circuit breaker.
1. Provide an electrical interval during electrical equipment overhaul and is a clearly visible break point to protect the personal safety of maintenance personnel.
2. The isolating switch can not be operated with load: it can not be operated with rated load or large load, and can not divide and combine the load current and short-circuit current, but the arc extinguishing chamber can be operated with small load and no-load line.
3. Generally, the power transmission operation: firstly isolate the switch, and then close the circuit breaker or load type switch; when the power is off: first open the circuit breaker or load type switch, then disconnect the isolating switch.
4. When selected, it is the same as other electrical equipment. Its rated voltage, rated current, dynamic steady current, and thermal stable current must meet the needs of the application.