Medium-voltage switchgear [/ˈmedium-voltage ˈswitkhgiːr/] n - Switchgear is the assembly of circuit breakers, busbars, disconnects, and protective relays that governs and wards the power arriving from the Where the Grid Comes In. At medium voltage (roughly 11–35 kV) it is the first place inside the fence where a human hand may safely isolate part of the system.

Its three offices:

• Protection [/ˈprɒtɛktɪɒn/] n - relays discern faults (short circuits, overloads, ground faults) and trip breakers within a few cycles to contain the harm.
• Isolation [/ˈɪsɒlætɪɒn/] n - sections may be de-energized so crews can work upon transformers or feeders without dropping the whole site, the very essence of a concurrently maintainable design (see Redundancy topologies).
• Switching [/ˈswɪtkhɪng/] n - feeds may be shifted between utility sources or onto the bus fed by the The Standby Engine.

Downstream, step-down transformers render the medium voltage into the low-voltage The Current That Comes in Threes that supplies the Uninterruptible power supply and the Power distribution unit. Right Grounding and bonding of the switchgear and its neutrals is what lets the protective relays “see” ground faults at all.

Part of The Engines of the Hall.