Configuration of air switch in building distribution box

Air switches in a distribution box should be selected and arranged according to circuit type, load, and safety requirements, with proper wiring of phase and neutral lines.

Air Switch Selection

Main switch: Typically a double-pole 32–63A air switch or isolation switch for household distribution boxes, ensuring full disconnection of phase and neutral lines in case of faults. Lighting circuits: Use 10–16A air switches. Socket circuits: Use 16–20A air switches; high-power appliances may require 20A.

Air conditioning circuits: Use 16–25A air switches, often on a dedicated circuit. Pole configuration: Single-phase circuits generally use 1P+N (phase + neutral), while three-phase circuits require 3P or 4P switches depending on the system.

Circuit Division and Arrangement

Dedicated circuits: Each air conditioner, kitchen outlets, and bathroom outlets should have separate circuits for safety and load management. General outlets and lighting: Can be grouped into one or two circuits depending on total load. Switch placement: Arrange switches from left to right inside the distribution box, with reserved positions for main and sub-switches, typically on the right side.

Wiring Guidelines

Zero (neutral) line: Use blue wires; lighting and socket circuits typically use 2. 5mm² wire, air conditioning circuits may use 2. 5–4.

0mm². Phase and neutral separation: Do not share neutral lines between different phases; each phase's neutral should only connect to its corresponding circuits. Routing: Wiring from the main switch to sub-switches generally goes to the left, while outgoing lines from the distribution box go to the right.

Safety Considerations

Leakage protection: In humid or outdoor areas, pair air switches with 2P leakage protectors for additional safety. Short-circuit and overload protection: Ensure the air switch rating matches the connected load to prevent overheating or tripping. Compliance: Follow local electrical codes and manufacturer specifications for installation, especially for three-phase or high-voltage systems.

Practical Example

A typical household distribution box may include: 1 main 2P switch (32–63A)2–3 lighting circuits (10–16A each)2–3 general outlet circuits (16A, 20A for high-power appliances)1 dedicated air conditioning circuit (16–25A)Optional spare circuits for future expansion This configuration ensures safe operation, proper load distribution, and compliance with electrical standards, while allowing flexibility for future additions.