The Golden State: Where & How to Live, Secure, Visit, Enjoy and Thrive in California

Practical Electricity And House Wiring

Principles Of Circuits

This chapter will explain how sockets, switches, and other devices are joined with wires so that the entire system is under the control of the owner, so that lights can be turned on and off as desired; devices such as lamps, flatirons, motors, etc., plugged in and used as needed; in short, so that the user will have a maximum ;r convenience and utility available from his electrical installation.

The installation must be made:

(a) for maximum convenience and utility for the user.
(b) in accordance with standard practice so as to be an entirely safe installation (using Underwriters' approved materials and meeting Code requirements).
(c) adequate so that alterations and additions will not have to be made later.

Circuits.—The simplest form of circuit is shown in Fig. 21, being merely two wires from the Line (the word "Line" will be used throughout this book to represent the source of electricity:—generator, battery, or Power Company's line) to a socket in which a lamp has been inserted.

Instead of picturing the socket and lamp, the arbitrary symbol of Fig. 22 to designate the lamp and socket will be used. Note also the method shown in Fig. 23 to indicate whether two wires crossing each other are connected together or not. This simple circuit is the circuit which would be used if you wanted to put only one lamp in a house or other building; to turn the lamp on and off, it would be necessary to unscrew the lamp in the socket.

In this elementary circuit, note the arrows indicating the course of the electricity from the Line, to the lamp, and back again through the other wire to the Line. Suppose now that we want to have a little more elaborate control, so the light can be turned on and off with a switch. Remember a switch is neither more nor less than a means of breaking or disconnecting one of the wires, so that we now have the circuit shown in Fig. 24, which is the same as Fig. 21 except that the switch has been added. The switch we have used is a simple porcelain base switch, where you can clearly see that when the blade is open, the wire is interrupted, no current can flow and the lamp cannot light.