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Auxiliary station fire alarm systems are broken into two types: local energyWhen a fire alarm signal is actuated in the protected premises, a circuit in the fire alarm control unit actuates the fire alarm box connected to the public fire alarm reporting system. Power to operate the fire alarm box comes from the fire alarm system in the protected premises. This allows the fire alarm control unit to monitor the connection to the box and whether it is set or not. and shunt-typeSome public fire alarm reporting systems use shunt-type boxes rather than local energy boxes. A closed contact at the protected premises is electrically connected to a circuit that is derived from the public circuit. When the closed contact opens the circuit, the shunt is removed. The box then trips and the signal is sent. If an open circuit occurs on the public fire alarm reporting system, there is no way that the shunt can cause the box to trip. Thus, the protected premises owner will not know the system is out unless the fire department notifies everyone on the circuit. Automatic fire detectors can’t be connected to a shunt-type circuit, but water flow switches and manual fire alarm boxes are allowed. Because the public circuits in a shunt-type system have to enter the protected premises, there is always the possibility that there could be damage in the protected premises that will be out of the fire department’s control. For this reason, many municipalities do not allow the use of shunt systems. systems.
Further, the box used to connect to the public reporting system is either a master boxA master box is a fire alarm box that is, or can be, activated by the building fire alarm system but also has manual operation capabilities, so it can also be publicly accessible. or an auxiliary boxAn auxiliary box is, or can be, activated by the building fire alarm system but does not have manual operation capability., or telephone box.
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