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are to be used. Those with which the public are most familiar are shown in Fig. 24.
They consist of a spindle mounted on a non-conducting base, and having arranged upon it a metallic piece, which, by turning the handle attached to the spindle, is brought into contact with metallic pieces to which the line wires
![](http://upload.wikimedia.org/wikipedia/commons/thumb/0/09/Incandescent_Electric_Lighting_-_Fig_24.png/175px-Incandescent_Electric_Lighting_-_Fig_24.png)
Fig. 24.
are secured by suitable binding screws thus closing the circuit.
The spindle is turned against the stress of a spring, so as to break the circuit quickly, when, by rotating the spindle, the bar mentioned is released from the metallic line wire contact-pieces. These switches are made of different sizes for carrying different strengths of current.