Standard dimensions of distribution box and outgoing cable box

Distribution boxes and outgoing cable boxes vary by application, but typical residential and commercial units range from 7–20 modules with dimensions designed for safe cable entry and adequate wiring space.

Distribution Box Dimensions

Residential and commercial distribution boards are commonly modular, with module counts ranging from 7, 10, 15, to 20 modules. The width of a single module is typically 18 mm, so a 10-module board would be approximately 180 mm wide, while a 20-module board would be around 360 mm wide. Heights are generally around 400–450 mm, and depths range from 100–150 mm, providing sufficient space for wiring and breakers . Industrial or higher-capacity distribution boxes (e.g., 63–315 KVA) have larger dimensions to accommodate busbars, isolators, and outgoing feeders. For example, busbar strips for 63/100 KVA boxes are 72×50×8 mm, while for 160/315 KVA boxes they are 120×50×15 mm. Feeders and incomer droppers are sized accordingly, with 50×8 mm for smaller boxes and 50×15 mm for larger boxes . Outdoor LT distribution boxes are typically fabricated from 2 mm GI sheet steel, with reinforced bodies, slanted roofs, and IP-55 protection. They include provisions for incoming and outgoing cable glands, often with detachable plates for cable fixing, and internal mounting strips for MCCBs .

Outgoing Cable Box Dimensions

Outgoing cable boxes are designed to provide safe cable entry and termination. Standard features include:

• Bottom plates of around 125×125 mm with holes and rubber glands for cable entry .
• Rubber glands with internal diameters suitable for the cable size, often with a 1 mm thick sealing film.
• Adequate spacing between outgoing feeders and busbars to prevent overheating and allow maintenance.
• Hinged doors with overlapping collars and gaskets to prevent dust and water ingress, typically conforming to IP-33 to IP-55 depending on indoor or outdoor use .

Key Considerations

• Module count determines width and internal space.
• Depth must accommodate wiring and breaker height.
• Cable entry points should match the number and size of incoming/outgoing cables.
• Protection rating (IP/NEMA) ensures suitability for indoor or outdoor installation.
• Busbar and feeder sizes must match the load capacity of the installation. By selecting distribution and outgoing cable boxes according to these dimensions and specifications, installers can ensure safe, compliant, and efficient electrical distribution in residential, commercial, or industrial settings .