How does the use of power line wiring conflict with CAN/ULC-S524 and Part 1, Section 32 of the Canadian Electrical Code?
The Fire-Link system is considered a ‘Control Unit Accessory’ as are power line 120VAC magnetic door holders and security door releasers which are also connected to a fire alarm control panel. In all building wiring, the Neutral and Ground are intentionally bonded at some point in the system, usually at the service transformer. The Neutral wire is the current carrying conductor and the Ground wire is the fault carrying conductor. Since these two wires are bonded, there is no electrical potential difference between these two wires. One of the intents of ground fault supervision is to detect a fault in the wiring such that if one of the conductors of the zone alarm initiating wiring is shorted to ground, a subsequent short of the other conductor does not cause an alarm condition. Fire-link inherently supervises the power line. If a fault between Ground and Neutral occurs, and if the buildings’ ground fault detection interruption devices fail to operate, the signal path for the Fire-Link
