Operation And Maintenance Of Residual Current Circuit Breakers

In addition to complying with standard electrical equipment installation procedures, the following points should be noted:

 

1. The installation of the residual current device (RCD) should conform to the manufacturer's product manual.

 

2. RCDs marked with the power supply side and load side must not be connected in reverse. Reversal will prevent the tripping coil of the electronic RCD from disconnecting when the power is cut off, leading to prolonged energization and burnout.

 

3. Installing an RCD should not remove or abandon existing safety protection measures; the RCD should only be used as an additional protection measure in the electrical safety protection system.

 

4. When installing an RCD, the neutral conductor and protective conductor must be strictly distinguished. When using three-pole four-wire or four-pole four-wire RCDs, the neutral conductor should be connected to the RCD. The neutral conductor passing through the RCD must not be used as the protective conductor.

 

5. The working neutral conductor must not be repeatedly grounded on the load side of the RCD; otherwise, the RCD will not function properly.

 

6. For branches using residual current devices (RCDs), the neutral wire can only be used as the neutral wire for that circuit. Connecting it to the neutral wire of other circuits is prohibited, and other lines or equipment cannot use the neutral wire of a line or equipment already equipped with an RCD.

 

7. After installation, the completed RCD must be tested according to Clause 3.1.6 of the "Code for Acceptance of Construction Quality of Building Electrical Engineering (GB50303-2002)," which states that "RCDs for power and lighting projects should undergo simulated operation tests," to ensure its sensitivity and reliability. During the test, the test button should be operated three times, with the circuit switching on and off under load three times. Only after confirming correct operation can it be officially put into use.

 

The safe operation of RCDs relies on a set of effective management systems and measures. In addition to regular maintenance, the operating characteristics of the RCD (including leakage current operating value and operating time, leakage non-operating current value, etc.) should be tested periodically, and test records should be kept and compared with the initial installation values ​​to determine if there have been any changes in quality.

 

When using a residual current device (RCD), follow the instructions in the user manual and perform a monthly check as required. This involves pressing the test button on the RCD to check if it can properly disconnect the power supply. During the check, be careful not to press the test button for too long; a short, intermittent press is sufficient. Also, avoid pressing it too many times to prevent burning out internal components.

 

If the RCD trips during use and no cause is found after inspection, one trial power restoration is permissible. If it trips again, investigate the cause and locate the fault. Do not attempt to continuously restore power.

 

If the RCD is damaged and unusable, immediately have it inspected or replaced by a professional electrician. If the RCD malfunctions or fails to trip, the reasons may include...