Dimensions of a 7-Channel Circuit Breaker Distribution Box

A typical 7-channel distribution box is designed to accommodate seven standard 18mm MCBs, resulting in an approximate width of 126mm, with height and depth varying by manufacturer, usually around 250–300mm high and 100–120mm deep.

Width Calculation

Most standard MCBs are 18mm wide per pole. For a 7-channel single-pole setup, the total width is calculated as: 7 × 18mm = 126mm. If RCBOs or higher-current MCBs are used, the width per module may increase to 27mm, which would make the total width 189mm .

Height and Depth

The height of a 7-way distribution box typically ranges from 250mm to 300mm, depending on the enclosure design and space for neutral and earth bars, wiring, and accessories. The depth is usually 100–120mm, allowing sufficient room for cable entry, internal wiring, and safe spacing between live parts .

Internal Layout Considerations

• Neutral and Earth Bars: Must be positioned to allow easy connection of all circuits.
• DIN Rail Space: Standard 7-way boxes include a DIN rail long enough to mount all breakers with proper spacing.
• Cable Room: Adequate space is provided for incoming and outgoing cables, often with adjustable depth up to 20mm for installation flexibility .
• Heat Dissipation: Larger enclosures or spacing between breakers may be required for high-current applications to prevent overheating .

Summary

For a 7-channel distribution box:

• Width: ~126mm (standard MCBs) or up to 189mm (larger modules)
• Height: ~250–300mm
• Depth: ~100–120mm
• Additional Features: Neutral/earth bars, DIN rail, cable entry space, adjustable depth for installation . These dimensions ensure safe installation, proper wiring, and compatibility with standard breakers while allowing room for future expansion or accessories.