Thickness of the secondary distribution box

The typical sheet metal thickness for secondary distribution boxes ranges from 1.2mm to 2.0mm, depending on type, size, and environmental conditions.

Recommended Thickness by Type

• Lighting Distribution Boxes: Used for small loads such as lighting circuits. For boxes ≥ 600mm, 2.0mm cold-rolled steel is recommended; for boxes < 600mm, 1.5mm is sufficient .
• Power Distribution Boxes: Designed for higher loads and mechanical stresses. Minimum thickness is 1.5mm, with larger or high-capacity boxes often using 2.0mm or more .
• Power Distribution Cabinets: For centralized control of large electrical loads, a minimum of 2.0mm is recommended to ensure structural integrity and protection during faults .

Thickness Based on Size

• Width 500–800mm: minimum 1.2mm
• Width ≥ 800mm: minimum 1.5mm
• Household box semi-perimeter ≥ 900mm: minimum 1.5mm; < 900mm: minimum 1.2mm .

Larger boxes require thicker metal to prevent deformation under the weight of installed equipment and maintain stability.

Environmental and Protection Considerations

• Indoor, dry environments: Standard thickness as per type and size is sufficient.
• Outdoor, humid, or corrosive environments: Thicker sheet metal is recommended, along with anti-corrosion treatments such as galvanized steel or anti-corrosion paint .

Practical Examples

• Eaton XBoard secondary distribution boxes use 2mm sheet steel for robust construction and safety .
• Mounting strips inside distribution boxes are often 2mm thick CRCA MS strips to support components securely .

Summary

Selecting the correct thickness ensures mechanical strength, safety, and longevity of the distribution box. For most secondary distribution boxes, 1.5–2.0mm is standard, with adjustments based on load, size, and environmental exposure. Proper thickness also facilitates safe installation of breakers, busbars, and other internal components.