Appendix C: Checking System Wiring; Using The Volt/ Ohm Meter; Meter Readings - Simplex 4100ES Installation Manual

14 Appendix C: Checking System Wiring

This appendix contains instructions on how to use a volt/ohm meter to check system wiring.
14.1

Using the Volt/ Ohm Meter

When using the volt/ohm meter to check each circuit, make sure to adhere to the notes and instructions below.
Note:
• Ensure that no power is applied to the FACU and that all wiring is properly connected (terminal blocks, LED/switch module ribbon
cables, etc.).
• Use the green grounding lug in the control panel for all measurements to ground.
• Each circuit must test free of all grounds and extraneous (stray) voltages.
• If there are problems removing all power from the fire alarm system, there is an alternate method of testing for stray voltage. The
wires may be lifted from the panel and terminated with appropriate resistors. Use 3.3 Kohms across conductor pairs and 50 Kohms
from any conductor under test to ground. All conductors must read less than 1.0V AC or DC.
Use the volt/ohm meter as described in the steps below to check each circuit type.
1. At the control panel, locate wires from each initiating device or indicating appliance circuit.
2. Check each circuit for extraneous voltage by setting the volt/ohm meter to AC. Place the meter probes so that the black probe is
on the "-" wire and the red probe is on the "+" wire. Meter readings must show less than 1.0 VAC.
3. Set the volt/ohm meter to DC and repeat step 2. The meter must read less than 1.0 VDC.
4. Test all conductors for voltage to ground. The meter must read no more than 1.0V AC or DC.
5. Set the volt/ohm meter to OHMS and place the meter probes as described in step 2. Check the circuits using the resistance
measurements in Table Table 19. Locate and correct any abnormal conditions at this time.
Note: If the reading indicates an open circuit in an initiating circuit, make sure the smoke detector heads are properly mounted
and seated. The circuit may be open if smoke detector power is not present, and if separately powered 4-wire devices are used.
6. Check all other system wiring to verify that each circuit is free of grounds and extraneous voltages.
14.2 Checking System Wiring
14.2.1

Meter Readings

Table 19 lists the correct meter readings for indicating appliances and initiating devices.
Circuit Type
Class B Initiating Device (Zone) Circuit
From zone + to zone – (each zone)
From zone + to ground
From zone - to ground
Class A Initiating Device (Zone) Circuit
From zone + to zone – (each zone)
From zone + to ground
From zone - to ground
From zone + OUT to + IN
From zone - OUT to - IN
Class B Notification Appliance Circuit (each signal circuit)
From + to ground
From - to ground
Resistance across circuit:
In one direction
In opposite direction
Class A Notification Appliance Circuit (each signal circuit)
From + to ground
From - to ground
From zone + OUT to + IN
page 123
Table 19: Acceptable Zone and Signal Circuit Meter Readings
4100ES Fire Alarm System Installation Guide
Meter Reading
3.3 K Ohms
Infinity
Infinity
Infinity
Infinity
Infinity
Less than 25 Ohms
Less than 25 Ohms
Infinity
Infinity
End-of-line-resistance (10k default)
Less than 200 Ohms
Infinity
Infinity
Less than 50 Ohms
574-848 Rev. BQ