High Voltage Switch Gear

Question 1

What are the two types of switch gear?

Answer 1

1. Metal-clad - The CB, bus-bars, disconnect devices and all the equipment required to control the individual circuit is assembled in metal compartments, and the circuit-breaker can be readily removed from the cubicle. The CB is on rollers (racked/roll out) and can be withdrawn horizontally and disconnected from the busbars after it is tripped.
2. Metal enclosed - has the CB, bus-bars, disconnect devices, and all the equipment required to control the individual circuit, assembled in metal compartments. These also include plexiglas windows for proper inspection

Question 2

What are the four most common types of switches?

Answer 2

1. Isolating - is designed for operation under no load. It is a mechanical switching device which, in the open position, provides a visible isolating distance. These switches have no auxiliary contacts or arc-quenching aids, and are strictly for isolating purposes.
2. Load Break - is a mechanical switch which is able to make, carry, and interrupt normal-load currents. Most are air-break types, and can be designed for indoor and outdoor applications
3. Disconnect - is a device which, in the open position, provides a visible isolating distance.
4. Horn Gap - can interrupt small-load currents. It is a pole-mounted, air-break switch, with auxiliary contacts; and has a main contact and an arcing-horn contact attachment. Maximum interrupting rating of these switches is 15 A, and they are used mainly on rural overhead distribution lines.