Dimensions of Indoor Secondary Distribution Box

Indoor secondary distribution boxes typically range in size depending on capacity, with standard wall-mounted steel boxes accommodating 100 to 1340 pairs and offering compact, modular designs for indoor installations.

Overview

Indoor secondary distribution boxes (SDBs) are used to receive power from a main distribution source and distribute it safely to multiple branch circuits in residential, commercial, or light industrial environments . They are designed for protected indoor environments, such as utility rooms, offices, or technical areas, where exposure to moisture, dust, or harsh weather is limited .

Typical Dimensions and Capacities

• Standard modular steel boxes: Lightweight steel enclosures for LSA-PLUS® modules are available in multiple sizes, supporting capacities from 340 to 1340 pairs .
• Series examples: Boxes in the 500 series include models 510, 520, 530, and 540, each with stainless steel backmount frames to support 100-, 200-, or 400-pair modules .
• Door and access: Removable and lockable doors provide 180-degree access, and doors can be hinged left or right depending on installation requirements .
• Material and finish: Typically made of mild steel with powder-coated finishes (e.g., RAL 7032 or RAL 7035) and rated IP20 for indoor protection .
• Mounting: Wall-mounted options are common for indoor use, allowing compact installation without occupying floor space . Floor-standing versions are used for larger systems requiring more internal space and higher load capacity .

Additional Features

• Cable management: Jumper rings and internal frames allow tidy cable routing and easy maintenance .
• Customization: Terminal blocks can be fitted for custom wiring, and some models allow integration of overvoltage protection products .
• Aesthetic and safety considerations: Modern designs include lockable doors, curved edges, and hidden hinges for a neat appearance and safe operation .

Summary

While exact external dimensions vary by manufacturer and capacity, indoor secondary distribution boxes are modular, compact, and designed to accommodate a range of circuit capacities from small residential setups to larger commercial installations. Wall-mounted steel boxes typically provide sufficient space for 100–1340 pairs, with removable doors and internal frames for organized wiring and easy maintenance .