Protecting the Alarm System from Lightning
Fire departments generally are awakening to the importance of adequately safeguarding their alarm systems from lightning, and as insurance against damage to delicate, costly instruments, are installing lightning arresters. A type of arrester popularly used by fire departments is known as the “Vac-M.” One of these installations which has given good results for three years on fire and police equipment is outlined as follows:
The “Vac-M” arresters were installed in engine houses, police stations, at all terminal points, and in the central office on the general protector board which consisted of wires ended on switches which distribute through fuses and heat coils before the finer office apparatus, the arresters were placed ahead of the fuses and sneak current coils. The service was never interrupted by static discharges, all high tension crosses were taken care of by the “Vac-M” without destroying heat coils or fuses whenever the sneak current was of sufficient voltage to operate (500 volts or over)—otherwise, the heat coil operated. No loss of instruments was experienced.