Horizontal switch of primary distribution box at construction site

The horizontal switch of a primary distribution box must be installed within 3 meters of the controlled equipment, in a ventilated, dry, and accessible location, following hierarchical distribution standards.

Placement and Distance Requirements

At construction sites, the primary distribution box is typically positioned near the main power supply, with distribution boxes and switch boxes arranged hierarchically below it, and electrical equipment below the switch box. The horizontal switch must be located no more than 3 meters horizontally from the fixed electrical equipment it controls. If this distance is exceeded, the switch box should not be used for distribution to that equipment.

Additionally, the distance between the distribution box and the switch box should not exceed 30 meters to ensure safe and efficient power delivery.

Installation Environment

Switch boxes and distribution boards must be installed in ventilated, dry, and normal temperature areas. They must be protected from gas, smoke, steam, liquids, vibration, impact, and heat sources. Adequate space should be provided around the boxes to allow two people to work simultaneously, and the area should be free of obstacles, weeds, or shrubs.

Material and Construction Standards

Switch boxes should be made of iron plates or high-quality insulating materials, with iron plate thickness exceeding 1. 5 mm. Electrical equipment inside the box should be mounted on metal or non-wood insulating plates and securely fastened to the box shell.

The metal plate and box shell must be electrically connected to ensure proper grounding.

Wiring and Safety

All connections inside the switch box must use insulated wires, with no loose joints or exposed live parts. The working neutral line should be connected through a terminal board, separated from the maintenance neutral line. Power and lighting circuits should be separated, either in different boxes or clearly segregated within the same box.

Summary

For a horizontal switch at a construction site: Keep it within 3 meters of the controlled equipment. Ensure ventilation, dryness, and accessibility. Use proper materials and secure mounting.

Maintain safe wiring practices and separation of circuits. Follow hierarchical distribution from main distribution box to switch box to equipment. This setup ensures safety, operational efficiency, and compliance with construction site electrical standards.