What Should Be Noted During the Installation Process of Indoor Load Switches?

The installation quality of indoor load switches directly affects their operational safety and service life. It must be carried out focusing on four core principles: "safety protection, standardized wiring, mechanical compatibility, and insulation assurance." Specific precautions are as follows:

1.Basic Preparation and Safety Protection Before Installation: Verify that the switch model and specifications (e.g., rated voltage, current) match the actual power distribution requirements to avoid "using a lower-capacity switch for a higher load." Inspect the switch for any physical damage and ensure all components (e.g., operating mechanism, fuse holder) are complete and intact. Check that insulating parts (e.g., porcelain insulators, insulating barriers) have no cracks. The installation environment must meet requirements—keep away from damp, dusty, or corrosive gas areas. Allow sufficient operating space in front of the cabinet (typically ≥1.2m), and ensure no flammable materials are nearby. It is essential to disconnect the upstream power supply first and hang a "Do Not Close" sign to prevent live working.

2. Strict Compliance with Mechanical Installation Standards: When securing the cabinet, use a level to ensure the cabinet is vertically aligned (deviation ≤1.5‰) and firmly fixed to prevent vibration during operation that could loosen wiring. Connection bolts between the switch body and cabinet should be tightened evenly to avoid uneven stress that might damage insulating components. After installing the operating mechanism (e.g., handle, linkage), perform a trial operation to ensure smooth and unobstructed opening and closing actions. When closed, the moving and fixed contacts should make tight contact (check contact gap with a feeler gauge, typically ≤0.1mm). When open, there must be a clear "visible break point" to meet safety isolation requirements.

3. Ensuring Electrical Safety During Wiring: Before wiring, verify the terminal markings on the switch (e.g., "Line Input L," "Neutral Output N") to ensure correct wiring direction and prevent operational faults due to reversed connections. The wire size must match the switch's rated current (e.g., use ≥16mm² copper wire for a 100A switch). Wire terminations should be securely crimped and tinned to prevent poor connections and overheating. Terminal bolts must be tightened to the specified torque (refer to the product manual; typically 8–10 N·m for an M8 bolt) to prevent arcing due to loosening. Additionally, phase, neutral, and ground wires should be routed separately, with insulation intact to prevent cross-contact between circuits. The grounding terminal must be reliably connected to earth (ground resistance ≤4Ω) to ensure safety during leakage events.

4. Inspection and Documentation After Installation: First, perform insulation testing using a megohmmeter to measure insulation resistance between phases and from phase to ground (insulation resistance ≥1000 MΩ for 10kV switches, ≥0.5 MΩ for low-voltage switches) to rule out insulation issues. Next, conduct no-load open/close tests (typically 3–5 operations) to observe whether the operation is normal and whether any abnormal sounds occur. After all checks are passed, organize the installation records, noting the switch model, installation location, test data, etc., for future maintenance. For high-voltage load switches, professional personnel should also be contacted to perform a withstand voltage test to ensure compliance with power regulations.