||This article includes a list of references, related reading or
external links, but its sources remain unclear because it lacks
inline citations. (March 2013)| ||This article's tone or style
may not reflect the encyclopedic tone used on Wikipedia. (March
2013)| In an electric power system, switchgear is the
combination of electrical disconnect switches, fuses or circuit
breakers used to control, protect and isolate electrical
equipment. Switchgear is used both to de-energize equipment to
allow work to be done and to clear faults downstream. This type
of equipment is important because it is directly linked to the
reliability of the electricity supply. The very earliest central
power stations used simple open knife switches, mounted on
insulating panels of marble or asbestos. Power levels and
voltages rapidly escalated, making opening manually operated
switches too dangerous for anything other than isolation of a
de-energized circuit. Oil-filled equipment allowed arc energy to
be contained and safely controlle