578 



ELECTRICAL EQUIPMENT 



Disconnecting switches are usually operated by means of an 

 insulating rod or switch hook which is made of selected material 

 especially treated for the purpose and capable of safely with- 

 standing the operating voltage. For medium voltages, holes are 

 provided in the ends of the switch blades for the insertion of the 

 hook, but for higher voltages where the length of the handle may 



FIG. 370. 110,000-volt Outdoor Transformer and Switching Station. 



be up to 15 feet or more, it becomes difficult to insert the hook 

 and this is provided on the switch blade instead, as will be noted 

 from the illustration. Sometimes means are provided for ground- 

 ing the handle when in use. 



When disconnecting switches are so mounted that the blade 

 forms the portion of a loop, the switch may be thrown open by 



