Справочник Пользователя для Pelco EH3515

Скачать
Страница из 20
 
14
C478M-M  (1/06)
 
Example: An enclosure that requires 30 VA and is installed 94 feet (28 m) from the transformer 
would require a minimum wire gauge of 20 AWG.
 
NOTE: 
 
 Distances are calculated in feet; values in parentheses are meters
.
*Minimum Cable Requirements
75 Ohms Impendance
All-copper center conductor
All-copper braided shield with
95% braid coverage
 
Table B.  
 
24 VAC Wiring Distances
The following are the recommended maximum distances for 24 VAC applications and are 
calculated with a 10 percent voltage drop. (Ten percent is generally the maximum allowable voltage 
drop for AC-powered devices.)
 
Wire Gauge
 
Total VA
20 AWG 
(0.5 mm
 
2
 
)
18 AWG 
(1.0 mm
 
2
 
)
16 AWG 
(1.5 mm
 
2
 
)
14 AWG 
(2.5 mm
 
2
 
)
12 AWG 
(4.0 mm
 
2
 
)
10
283 (86)
451 (137)
716 (218)
1142 (348)
1811 (551)
 
Maximum distance from
transformer to load
 
20
141 (42)
225 (68)
358 (109)
571 (174)
905 (275)
30
94 (28)
150 (45)
238 (72)
380 (115)
603 (183)
40
70 (21)
112 (34)
179 (54)
285 (86)
452 (137)
50
56 (17)
90 (27)
143 (43)
228 (69)
362 (110)
 
Table C.  
 
Video Coaxial Cable Wiring Distances
 
Cable Type*
Maximum 
Distance
 
RG59/U
RG6/U
RG11/U
750 ft (229 m)
1,000 ft (305 m)
1,500 ft (457 m)