The Complete Guide to Switchgear
ENSOL Engineering TeamUpdated 2026-02-253 min read
Switchgear is the equipment that switches, controls and protects electrical circuits. This guide covers the main types, how they are tested and approved, and the structures that support them.
Key takeaways
- Switchgear switches and protects circuits; ratings must match the system.
- AIS (air) vs GIS (gas) differ in footprint and cost.
- Type-testing (e.g. CPRI) verifies rated performance.
- Support structures are galvanised for long outdoor life.
Types of switchgear
Air-insulated switchgear (AIS) uses air as insulation and suits open sites; gas-insulated switchgear (GIS) is compact and suits space-constrained or indoor use. Devices include isolators, circuit breakers (such as VCBs) and compact assemblies like RMUs.
Ratings, testing and approvals
Voltage class, current rating and short-circuit withstand must match the system. Type-testing at bodies such as CPRI, and utility/discom approvals, provide the assurance utilities require.