C-2
Table C-1 lists the correct meter readings for indicating appliances and initiating devices.
Table C-1. Acceptable Zone and Signal Circuit Meter Readings
Circuit Type Meter Reading
Class B (spur) Detector Circuit
From zone + to zone – (each zone)
3.3k (EOLR)
From zone + to ground Open circuit
From zone - to ground Open circuit
Class B (spur) Notification Appliance Circuit (each signal circuit)
From + to ground Open circuit
From - to ground Open circuit
Resistance across circuit:
In one direction
In the opposite direction
10 k (EOLR)
Low resistance (Load)
Class A (loop) Notification Appliance Circuit (each signal circuit)
From + to ground Open circuit
From - to ground Open circuit
From + OUT to + IN
Less than 50
From - OUT to - IN
Less than 50
Resistance across circuit:
In one direction
In opposite direction
Open circuit
Low resistance (Load)
Shielding
Shield to ground Open circuit
Shield to - Open circuit
Shield to + Open circuit
MAPNET/IDNet Loops
From MAPNET/IDNet + to ground Open circuit
From MAPNET/IDNet - to ground Open circuit
Note: measuring from MAPNET/IDNet B+ to A+, or B- to A- will nearly always read as
an open circuit due to the channel isolators in the loop.
Appendix C: Checking System Wiring, Continued
Meter Readings