3-4
Chapter 3 NAC Power Supply
NAC Section, Continued
Wiring Wiring Distances
Table 3-5 lists the maximum distances from the NAC terminal block to the last appliance in a
Class A configuration, depending on wire gauge and current. Use Table 3-5 to calculate wire
distances for your application if you are using Class A wiring. Table 3-6 gives the values for a
Class B configuration.
Note:
• Max Distance = distance from the power supply to last appliance.
• This table is calculated at 49
o
C (120
o
F). If you are installing in locations that could be exposed to
higher temperatures, refer to NEC Table 8.
• Distances are based on a 3 V drop, and take into account the worst-case panel output voltage.
• If circuit integrity wire is used instead of housing cable in a fire rated enclosure, reduce wiring distances
by 38 ft (12 m) for every 10 ft (3 m) of potential exposure.
Continued on next page
Table 3-5. Class A Wiring Distances
Alarm Current
Max Distance
w/ 18 AWG
(0.8231 mm
2
)
Max Distance
w/ 16 AWG
(1.309 mm
2
)
Max Distance
w/ 14
AWG
(2.081 mm
2
)
Max Distance
w/ 12 AWG
(3.309 mm
2
)
DC
Resistance
0.25 A 420 ft (128 m) 667 ft (203 m) 1,063 ft (324 m) 1,691 ft (515 m) 6 Ohms
0.50 A 210 ft (64 m) 334 ft (102 m) 532 ft (162 m) 845 ft (258 m) 3 Ohms
0.75 A 140 ft (43 m) 222 ft (68 m) 354 ft (108 m) 564 ft (172 m) 2 Ohms
1.00 A 105 ft (32m) 167 ft (51 m) 266 ft (81 m) 423 ft (129 m) 1.5 Ohms
1.25 A 84 ft (26 m) 133 ft (41 m) 213 ft (65 m) 338 ft (103 m) 1.2 Ohms
1.50 A 70 ft (21 m) 111 ft (34 m) 177 ft (54 m) 282 ft (86 m) 1 Ohm
1.75A 60ft (18m) 95ft (29m) 152ft (46m) 242ft (74m) 0.86 Ohm
2.00A 53ft (16m) 83ft (25m) 133ft (41m) 211ft (64m) 0.75 Ohm
2.25A 47ft (14m) 74ft (23m) 118ft (36m) 188ft (57m) 0.67 Ohm
2.50A 42ft (13m) 67ft (20m) 106ft (32m) 169ft (51m) 0.60 Ohm
2.75A 38ft (12m) 61ft (19m) 97ft (30m) 154ft (47m) 0.55 Ohm
3.00A 35ft (11m) 56ft (17m) 89ft (27m) 141ft (43m) 0.50 Ohm
Table 3-6. Class B Wiring Distances
Alarm Current
Max Distance
w/ 18 AWG
(0.8231 mm
2
)
Max Distance
w/ 16 AWG
(1.309 mm
2
)
Max Distance
w/ 14 AWG
(2.081 mm
2
)
Max Distance
w/ 12 AWG
(3.309 mm
2
)
DC
Resistance
0.25 A 840 ft (256 m) 1,335 ft (407 m) 2,126 ft (648 m) 3,382 ft (1,031 m) 12 Ohms
0.50 A 420 ft (128 m) 667 ft (203 m) 1,063 ft (324 m) 1,691 ft (515 m) 6 Ohms
0.75 A 280 ft (85 m) 445 ft (136 m) 709 ft (216 m) 1,127 ft (344 m) 4 Ohms
1.00 A 210 ft (64 m) 334 ft (102 m) 532 ft (162 m) 845 ft (258 m) 3 Ohms
1.25 A 168 ft (51 m) 267 ft (81 m) 425 ft (130 m) 676 ft (206 m) 2.4 Ohms
1.50 A 140 ft (43 m) 222 ft (68 m) 354 ft (108 m) 564 ft (172 m) 2 Ohms
1.75 A 120 ft (37 m) 191 ft (58 m) 304 ft (93 m) 483 ft (147 m) 1.71 Ohms
2.00 A 105 ft (32 m) 167 ft (51 m) 266 ft (81 m) 423 ft (129 m) 1.5 Ohms
2.25 A 93 ft (28 m) 148 ft (45 m) 236 ft (72 m) 376 ft (115 m) 1.33 Ohms
2.50 A 84 ft (26 m) 133 ft (41 m) 213 ft (65 m) 338 ft (103 m) 1.2 Ohms
2.75 A 76 ft (23 m) 121 ft (37 m) 193 ft (59 m) 307 ft (94 m) 1.09 Ohms
3.00 A 70 ft (21 m) 111 ft (34 m) 177 ft (54 m) 282 ft (86 m) 1 Ohm
To Next Page
Loading...
