FireLite SLC Wiring Manual — P/N 51309:P4 9/17/2014 23Section 4: SLC Circuits with Isolators4.1 Fault Isolator DevicesThere are three isolator devices used to protect critical elements of the SLC from faults on otherSLC branches or segments.• Fault Isolator Module I300• Six Fault Isolator Module ISO-6• Isolator Detector Base B224BIA Fault Isolator Module on both sides of a device, or the combination of Isolator Base and IsolatorModule is required to comply with NFPA Style 7 requirements.4.1.1 Isolating an SLC BranchThe module continuously monitors the circuit connected to terminals 3(–) and 4(+). Upon power-up, an integral relay is latched on. The module periodically pulses the coil of this relay. A short cir-cuit on the SLC resets the relay. The module detects the short and disconnects the faulted SLCbranch or segment by opening the positive side of the SLC (terminal 4). This isolates the faultybranch from the remainder of the loop preventing a communication problem with all other address-able devices on the remaining branches (labeled “Continuation of the SLC” in the figure below).During a fault condition, the control panel registers a trouble condition for each addressable devicewhich is isolated on the SLC segment or branch. Once the fault is removed, the module automati-cally reapplies power to the SLC branch or segment.! CAUTION: MAXIMUM ADDRESSABLE DEVICES• If relay or sounder bases are not used, a maximum of 25 addressable devices can beconnected between Isolator Modules and/or Bases. When relay or sounder bases are used,the maximum number of addressable devices that can be connected between Isolators isreduced to seven. Isolator modules will not function properly when these limits are exceeded.• When more than 100 Isolator Modules are connected to an SLC loop, the address capacityof the loop is reduced by two (2) addresses for every isolator device in excess of 100.
