Why you use ELR?

Answer 1

An ELR is terminology used in fire alarm systems. It stands for End of Line Resistor. It is used as a load on individual fire alarm circuits. This load draws a small current that is monitored by the alarm panel. What the panel is monitoring for is open circuits in break glass and bell circuits. If the current is non existent then it means that one of the fire circuits is opened, out of service and non operational. In the alarm panel a relay is de-energized and a trouble alarm is activated to bring attention to the problem. Once the problem is repaired the current again flows through the ELR and the trouble relay resets.