Lighting Distribution Box Switch Number

Switches in a lighting distribution box are numbered sequentially, starting from the incomer and progressing through circuits according to electrical importance, with each switch labeled for clear identification.

Numbering Principles

Each switch or circuit in a lighting distribution box (also called a sub-distribution board) is assigned a unique reference number. This number is typically prefixed by the electrical identification number of the distribution box to maintain consistency across schematics and physical labeling . The numbering sequence usually starts at the incomer switch and continues through the circuits in order of electrical importance, such as bus sections, transformer feeders, and individual lighting circuits .

Labeling and Identification

• Circuit Breakers (LS Switches): Each breaker controlling a lighting circuit is labeled with its PC reference number, which corresponds to the circuit's position in the schematic .
• Residual Current Devices (RCDs): RCDs are labeled to indicate the circuits they protect, especially in damp or outdoor areas .
• Zones and Functions: Lighting circuits can be grouped by room, zone, or function (e.g., indoor vs. outdoor, timer-controlled, motion sensor-controlled) to simplify maintenance and operation .

Practical Example

For a distribution box labeled DB1, the incomer might be numbered DB1-01, followed by sequential numbers for each lighting circuit: DB1-02, DB1-03, etc. If the box has multiple busbars (A and B), numbering can run sequentially through each busbar section to maintain clarity .

Benefits of Proper Numbering

• Safety: Quick identification of circuits during faults or maintenance.
• Maintenance: Easier troubleshooting and replacement of switches or breakers.
• Documentation: Consistency between schematics, interconnection diagrams, and physical labels ensures accurate record-keeping . By following these conventions, a lighting distribution box becomes organized, safe, and easy to manage, with each switch clearly identifiable both on the panel and in electrical documentation.