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Lightening rod
Communicate
arrester
Video arrester
Power arrester
45
°
conical
envelope
The resistance of
earthing conductor
must be less than 4 Ω.
The camera should be
within a 45
°
envelope
under the lightening rod.
Steel jacket
Lightning & Surge Protection
Wire gauge standards
Bare Wire Gauge(mm)
American Wire Gauge
(AWG)
Cross-sectional Area of
Bare Wire (mm
2
)
0.750
21
0.4417
0.800
20
0.5027
0.900
19
0.6362
1.000
18
0.7854
1.250
16
1.2266
1.500
15
1.7663
2.000
12
3.1420
2.500
4.9080
3.000
7.0683
12 Vdc Wire Gauge and Transmission Distance
The following table shows the recommended maximum distance adopted for the different wire sizes when
the 12 Vdc voltage loss is less than 15%. For example, for a device with the rating power of
20 VA which is installed 77 feet (22 m) from the transformer, the minimum wire gauge required is 1.0000
mm (18 gauge).
Power (VA)
Wire size mm (gauge)
0.800 (20)
1.000 (18)
1.250 (16)
2.000 (12)
10
97 (28)
153 (44)
234 (67)
617 (176)
20
49 (14)
77 (22)
117 (33)
308 (88)
24
41 (12)
64 (18)
98 (28)
257 (73)
30
32 (9)
51 (15)
78 (22)
206 (59)
40
24 (7)
38 (11)
59 (17)
154 (44)
48
20 (6)
32 (9)
49 (14)
128 (37)
50
19 (6)
31 (9)
47 (13)
123 (35)
60
16 (5)
26 (7)
39 (11)
103 (29)
70
14 (4)
22 (6)
33 (10)
88 (25)
80
12 (3)
19 (5)
29 (8)
77 (22)
90
10.8 (3.1)
17 (5)
26 (7)
69 (20)
100
9.7 (2.8)
15 (4)
23 (7)
62 (18)
110
8.9 (2.5)
14 (4)
21 (6)
56 (16)
120
8.1 (2.3)
13 (4)
20 (6)
51 (15)
130
7.5 (2.1)
11.8 (3.4)
18 (5)
47 (14)
140
7 (2)
11 (3.1)
17 (5)
44 (13)
150
6.5 (1.9)
10.2 (2.9)
16 (4)
41 (12)
160
6.1 (1.7)
9.6 (2.7)
15 (4)
39 (11)
170
5.7 (1.6)
9 (2.6)
14 (4)
36 (10)
180
5.4 (1.5)
8.5 (2.4)
13 (4)
34 (10)
