GE Security Vigilant VS1 - Page 216

Appendix B: Worksheets
204 Vigilant VS1 and VS2 Technical Reference Manual
appliances will be placed on the NAC. The cable is 12 AWG wire, and the
manufacturer specifies a wire resistance factor of 0.002 Ω/ft.
Itot = Ia
= 20 × 0.1 A
= 2 A
Vm = Vr − (Itot × K)
= 20.4 V − (2 A × 0.20 V/A)
= 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 44: VS1 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 45: VS2 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.