PLAN No. 1188. SIGNAL WIRING
In wiring for electric doorbells, fire and burglar alarms, and other so-called signaling circuits dry cells are ordinarily used to provide the voltage. With this low pressure the fire risk is almost negligible. While the signal wiring in a large factory or institution may be complicated, in smaller buildings or residences it offers few difficult problems. To install signal wire economically and properly, however, requires some skill and experience.