Medium-sized distribution box size specification table

Medium-sized distribution boxes typically range from 200–328 mm in length, 172–174 mm in width, and 95–140 mm in height, with capacities and features varying by application.

Electrical Distribution Boxes

Medium-sized electrical distribution boxes are low-voltage enclosures that safely distribute incoming power to multiple outgoing circuits through devices like MCBs, RCDs, RCBOs, fuses, isolators, and busbars. They are selected based on application type (residential, commercial, industrial), supply system (single-phase, three-phase, AC/DC), number of outgoing circuits, rated current, and short-circuit capacity. Internal layout considerations include DIN rail space, neutral and earth bars, cable entries, and heat dissipation. Enclosures are typically made of flame-resistant ABS plastic or metal, with IP ratings for dust and water protection, UV resistance, and impact protection .

Typical Dimensions (Plastic Medium Boxes)

• Length: 200–328 mm
• Width: 172–174 mm
• Height: 95–140 mm
• Material: Flame-resistant ABS plastic
• Standards: BS EN60439-3, JB/T7121-93
• Number of ways: Varies by model, typically 6–24 ways for medium boxes .

Fiber Optic Medium Distribution Wall Box (MDWB)

For fiber optic applications, a medium distribution wall box is designed for up to 168 fiber splices and can accommodate input cables of butt or in-line types. It supports 32 customer drop cables of 3–6 mm diameter and 4 cables of 6–12 mm diameter. Key specifications include:

• Dimensions: Width 250 mm × Height 280 mm × Depth 100 mm
• Cable entry: Top and bottom ports, with manifolds for easy fiber routing
• Splice trays: Single element or single circuit trays
• Protection rating: IP55, suitable for indoor or outdoor use
• Color options: White or dark grey
• Accessories: Cable ties, rubber grommets, and cable glands for secure installation .

Key Considerations for Selection

1. Application: Choose based on residential, commercial, industrial, or telecom use.
2. Number of ways/circuits: Include spare ways for future expansion.
3. Protection devices: Ensure compatibility with MCBs, RCDs, RCBOs, fuses, or surge protection devices.
4. Mounting and space: Wall-mounted or floor-mounted, with sufficient internal space for wiring and heat dissipation.
5. Environmental protection: IP rating, UV resistance, corrosion resistance, and impact protection.
6. Compliance: Ensure adherence to IEC, UL/NEC, or local electrical standards .

Medium-sized distribution boxes provide a balance between compactness and capacity, making them suitable for residential breaker panels, small commercial installations, or fiber optic distribution points. Proper selection ensures safety, expandability, and compliance with electrical standards.