2.3 NAC Circuit Wiring
For wiring sizes, see Section 6.5, "NAC Circuit Loop Wiring Requirements".
2.3.1 Four NACs Configured for Class B (Style Y)
Figure 2.10 shows four NACs configured for Class B (Style Y).
• Trouble on NAC1
LED1 SIG1 TRBL.
• Trouble on NAC2
LED2 SIG2 TRBL.
• Trouble on NAC3
LED3 SIG3 TRBL.
• Trouble on NAC4
LED4 SIG4 TRBL.
1. Typical ELR's for new installations can be 3.9k or 4.7k ohm.
2. The same gauge wire must be used if two conductors are connected to the same terminal of
any terminal block.
3. Do not complete a continuous circuit around the screw terminal. There must be two separate
wires on either side of the screw at the terminal block. "T-tapping" is absolutely NOT ALLOWED.
NAC 1 NAC 2
NACs 1 - 3 are wired the same as NAC4 and use
ELR the same as Reference Resistor.
Figure 2.10 Four NACs in Class B (Style Y)
HPFF12 NAC Expander — P/N 53576:B 11/24/2010
NAC Circuit Wiring
EOL same as
Alarm Polarity Shown