Network Wiring For Ground Fault Detection - Honeywell Notifier High-Speed NOTI-FIRE-NET Instruction Manual

Network Configurations

3.4 Network Wiring for Ground Fault Detection

Because the twisted-pair communication link between adjacent nodes is isolated from other nodes through the HS-NCM (transformer
coupling), a single ground fault on one of the wires will have no effect on circuit operation.
Network ground fault detection from a node power supply may be enabled or disabled with switches on the HS-NCM-W and ONYX-
Works-HNW. Refer to each product's related documentation for switch designation and ground fault detection setup.
NOTE: If both ground fault switches are set to the "OFF" position, ground fault detection for the HS-NCM is completely disabled.
Completely disabling ground fault detection is not recommended and is not in compliance with UL 864 Standards.
Ground fault detection may be provided by the following:
• NFS-3030 or NFS2-3030 node (powered by AMPS-24/E)
• NFS2-640, NFS-640, or NFS-320 node (own power supply)
• NCA or NCA-2 node powered by Main Power Supply (AMPS-24/E)
• DVC-EM node powered by Main Power Supply (AMPS-24/E)
• NCD node powered by Main System Power Supply or Auxiliary Power Supply
NOTE: ONYXWorks-HN does not detect ground fault, but ONYXWORKS-HNW can pass the signal between network nodes on either side
of ONYXWorks. Disabling ground fault detection will prevent signal feed-through.
Point-to-Point Configuration
In a point-to-point configuration, enable ground fault detection on only one side of each point-to-point connection. In Figure 3.4, the left
node provides the ground fault detection, and thus must be one of the ground fault detection nodes. SW4 on the HS-NCM is set to the
ON position to enable ground fault detection on the left HS-NCM Port B. The corresponding Port A switch of the right HS-NCM is set
to the OFF position, disabling ground fault detection for the node on the right. When a ground fault occurs on any HS-NCM connected
to the network, the ground fault will be detected by the power supply of the HS-NCM with ground fault enabled.
If an HS-NCM configured as a repeater is employed, two ground fault detection schemes are possible within a point-to-point configura-
tion. One or both nodes (refer to Figure 3.5 and Figure 3.6) may provide ground fault detection, depending on the number of repeaters
and the setting of the repeater ground fault detect switch (SW4) at each repeater (refer to EXAMPLES 1 and 2).
• EXAMPLE 1: In this example, the node on the left provides the ground fault detection, and thus must be one of the ground fault
detection nodes defined on page 12. S2 (Port B) of the HS-NCM on the left is set to the ON position to enable ground fault
detection on Port B. The repeater ground fault detection switch (SW4) is ON, allowing the left node to provide ground fault
detection for the two point-to-point wire connections on the left and right of the repeater. The Port A switch on the right HS-NCM
is set to the OFF position, disabling ground fault detection from the node on the right. The node on the right can be any network
node.
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12
Twisted-Pair Wire
Ports
GF Detect
Enabled
Power Supply
GF Detect
Enabled
Network Node
Figure 3.4 Point-to-Point Ground Fault Detection
Twisted-Pair Wire
Ports
GF Detect
Enabled
Power Supply
GF Detect
Enabled
Network Node
Figure 3.5 Point-to-Point (EXAMPLE 1)
Network Wiring for Ground Fault Detection
Ports
GF Detect Dis-
abled
Power Supply
Network Node
Twisted-Pair Wire
Ports Ports
GF Detect Dis-
abled
Power Supply
Network Node
High-Speed NFN Manual — P/N 54013:C4 8/8/2019