8-2
Checking system wiring
Overview This section contains instructions on how to use a multimeter to check system wiring
Using the
multimeter
When using the multimeter to check each circuit, make sure to adhere to the notes and
instructions below.
Note:
• Ensure that no power is applied to the 4010ES fire alarm panel and that all wiring is properly connected
(terminal blocks, LED/switch module ribbon cables, etc.)
• Use the grounding lug with the earth ground symbol inside 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 3.3K ohms across conductor pairs and 50K ohms connected from any conductor under
test to ground. All conductors must read less than 1.0V AC or DC.
Use a multimeter 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 multimeter to DC and repeat step 2. The meter must read less than 1.0 VDC.
4. Check all conductors for extraneous voltage to ground. The meter must read less than 1.0V
AC and DC.
5. Set the multimeter to OHMS and place the meter probes as described in step 2. Check the
circuits using the resistance measurements in Table 8-1. 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.
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