250 Electrical Power Systems Technology
Switching Equipment
In addition to circuit protection, power distribution systems must
have equipment that can be used to connect or disconnect the entire system
or parts of the system. Various types of switching devices are used to perform
this function. A simple type of switch is the safety switch. This type of switch
is mounted in a metal enclosure and operated by means of an external han-
dle. Safety switches are used only to turn a circuit off or on; however, fuses
are often mounted in the same enclosure with the safety switch.
Distribution Panelboards
Another type of switch is the kind used in conjunction with a cir-
Figure 9-4. Industrial cable tray raceway design (Courtesy Chalfant Manufacturing
Co.)