Kidde FX-64 - Page 203

Appendix B: Worksheets
P/N 3102352-EN • REV 005 • ISS 28DEC18 193
= 20.4 V − 0.40 V
= 20.0 V
Vd = Vm − Va
= 20.0 V − 16.0 V
= 4.0 V
Rmax = Vd / Itot
= 4.0 V / 2.0 A
= 2.0 Ω
Lc = (Rmax / Rw) / 2
= (2.0 Ω / 0.002 Ω/ft.) / 2
= (1,000.0 ft.) / 2
= 500.0 ft.
So the maximum wire run for this NAC would be 500 ft. (rounding down for safety).
NAC maximum wire run quick reference tables
Table 49: FX-64 panel
Current
12 AWG
14 AWG
16 AWG
18 AWG
0.5 A
2,228 ft.
1,400 ft.
879 ft.
553 ft.
1.0 A
1,088 ft.
684 ft.
429 ft.
270 ft.
1.5 A
708 ft.
445 ft.
279 ft.
175 ft.
2.0 A
518 ft.
326 ft.
204 ft.
128 ft.
2.5 A
404 ft.
254 ft.
160 ft.
100 ft.
Table 50: FX-1000 panel
Current
12 AWG
14 AWG
16 AWG
18 AWG
0.5 A
2217 ft.
1394 ft.
875 ft.
550 ft.
1.0 A
1,077 ft.
677 ft.
425 ft.
267 ft.
1.5 A
697 ft.
438 ft.
275 ft.
173 ft.
2.0 A
507 ft.
319 ft.
200 ft.
126 ft.
2.5 A
393 ft.
247 ft.
155 ft.
97 ft.