Fire Alarm Control Panels - Bosch Security Systems

Fire Alarm Control Panels Connection | en 35Add together the alarm existing current draw by all the devices on the wiring run to determinethe maximum allowed distance between the option bus terminals on the control panel and thelast device on the wire run (the device farthest from the control panel).To determine the maximum allowed length for the run, add up the total alarm load for optionbus devices on the wire run. For example, if the total load of option bus devices on aparticular run is 400 mA, the maximum length of the run can be up to 500 ft (152 m). No morethan 4 000 ft (1 219 m) of wire can be connected to the option bus terminals, even if theindividual lengths of the runs are all within limit.For the allowed lengths for18 AWG (1.2 mm) wire, see the following figure:Figure 5.9: 18 AWG cable length for existing current drawiNotice!The graph is for 18 AWG cable!For16 AWG (1.5 mm) wire, cable lengths can be 1.5 times longer. For14 AWG (1.8 mm) wire,cable lengths can be 2.5 times longer. The 4 000 ft (1 219 m) maximum length of connectedwire still applies.Bosch Security System, Inc. Installation and Operation Manual 2012.08 | 04 | F01U008458