Switchboard

A switchboard is an electrical distribution assembly that receives power from a single large incoming feed and divides it among several outgoing circuits, each protected by its own breaker or fused switch. Its emphasis is on routing and distributing power within a building rather than on the heavy compartmentalization and centralized fault control of switchgear. Switchboards typically operate at 600V or less while carrying high current, commonly 1,600A or more on the main bus.

Switchboard, switchgear, and panelboard

These three terms describe a hierarchy. Switchgear handles the highest voltages and fault levels, up to roughly 38 kV and 6,000A, with each device in its own isolated compartment for maximum protection and selectivity. A switchboard sits below it, focused on bulk low-voltage distribution. A panelboard sits below that, splitting power into final branch circuits at up to about 1,200A. In a mining facility the medium-voltage service typically lands on switchgear, feeds a low-voltage switchboard, which in turn feeds the panelboards and PDUs at each rack row.

What is inside

A switchboard houses a main bus fed from the incoming service, branch overcurrent devices, metering, and often surge protection. Because it concentrates high current in one enclosure, it is a focal point for arc flash analysis and benefits from arc-resistant construction.

The protective devices inside a switchboard are individual circuit breaker units coordinated by a protection relay scheme, and its high concentrated current makes arc flash a primary safety consideration.