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

Practical Electricity And House Wiring

Miscellaneous Useful Additions

In Chapters 8 to 16 we wired our house to cover the essential devices ordinarily used but did not cover such details as doorbell wiring, door openers, wiring to the garage, automatic closet switches.

Doorbells.—We covered the subject of transformers in Chapter 8; you learned that a transformer has two windings, the primary and secondary. In a transformer for doorbell use the primary connections are brought out in the form of wire leads about 6 inches long, and the secondary or low voltage windings are brought out to binding posts. Ordinarily there are only two posts and the voltage is on the order of 8 to 10 volts. Occasionally you will find a transformer with three binding posts which we will call numbers 1, 2 and 3. In that case the voltage between posts 1 and 2 is usually about 6 volts, between 2 and 3 about 8 volts and between 1 and 3, 14 volts, giving you a choice of voltages.

The primary is permanently connected, one lead going to the white wire, the other to the black wire at a point where you can trace it back to fuse cabinet without passing through a switch. In other words, the transformer must be connected at a point where a lamp would be permanently lighted if it were connected there.

Although the transformer is permanently connected to the circuit, no power is consumed except while the doorbell is ringing—this was covered also in Chapter 8.

The wiring on the low voltage side of the transformer is done with ordinary bell wire. Because the voltage is so low, and the amount of electricity available is very limited due to the design of the transformer, this wire can be stapled directly to the joists or studs. Doorbell transformers are so designed that even if the secondary circuit is short-circuited, no excessive amount of current will flow, and no harm is done.

If only one bell is to be used, the wiring is extremely simple, and Fig. 194 will require no clarification. Usually however, you will want a doorbell to operate from the push button at the front door and a buzzer to operate from the push button at the back door. The wiring for this is equally simple and is covered in Fig. 195.