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Sizing of De-Icer Control Box and Wiring

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Precautions:

CAUTION: It is YOUR responsibility to ensure that your installation meets all applicable codes.
We recommend that the installation be reviewed by a qualified electrician before you apply power.

Voltage Requirement:

The de-icer system requires 220 VAC, 50 - 60 Hz., single-phase.

Wire Sizing:

The size (gauge) of the electric wires required will depend on the current draw of your de-icer system. Table 1 shows approximate heater leg resistances and Table 2 shows approximate de-icer current draws for various models and sizes of Shively antennas.

NOTE: The resistance readings in Table 1 are for the Shively-supplied portion of the systems only, and do not take into account any long run of cable to the tower and up to the antenna.

Consult your electrician to determine the wire sizes required by the electric code applicable in your area.

Table 1. Heater Leg Resistances (ohms)
Antenna Size 6602 6600 High-Band 6600 Low-Band 6810 High-Band 6810 Low-Band
1-Bay
203
tbd
tbd
53
47
2-Bay
101
27
24
3-Bay
68
18
16
4-Bay
51
13
12
5-Bay
41
11
9
6-Bay
34
9
8
7-Bay
29
8
7
8-Bay
25
7
6
10-Bay,
single circuit
20
n/a
n/a
12-Bay,
single circuit
17
n/a
n/a
14-Bay,
single circuit
14
n/a
n/a
16-Bay,
single circuit
13
n/a
n/a
10-Bay,
each of 2 circuits
20
11
9
12-Bay,
each of 2 circuits
17
9
8
14-Bay,
each of 2 circuits
14
8
7
16-Bay,
each of 2 circuits
13
7
6
Antenna Size 6812B 6814
High-Band		 6814
Low-Band		 6813
High-Band		 6813
Low-Band
1-Bay
203
55
46
85
75
2-Bay
101
27
23
42
38
3-Bay
68
18
15
28
25
4-Bay
51
14
11
21
19
5-Bay
41
11
9
17
15
6-Bay
34
9
8
14
13
7-Bay
29
8
7
12
11
8-Bay
25
7
6
11
9
10-Bay,
single circuit
20
n/a
n/a
8
8
12-Bay,
single circuit
17
n/a
n/a
7
6
14-Bay,
single circuit
14
n/a
n/a
n/a
n/a
16-Bay,
single circuit
13
n/a
n/a
n/a
n/a
10-Bay,
each of 2 circuits
20
11
9
n/a
n/a
12-Bay,
each of 2 circuits
17
9
8
n/a
n/a
14-Bay,
each of 2 circuits
14
8
7
12
11
16-Bay,
each of 2 circuits
13
7
6
11
9

Cover open, not shown. Box dimensions are 300 mm (11.81 in) wide x 400 mm (15.75 in) high x 150 mm (5.90 in) deep.
Figure 1. Model 94068 De-Icer Control Box

Control Box Sizing

Shively Labs Model 94068 control boxes (Figure 1) come in three current capacities. If you are purchasing the Shively control box, refer to Table 2. Use the 10-amp box for up to 8 amps (20% safety margin), the 20-amp box for up to 16 amps, and the 30-amp box for up to 24 amps.

NOTE: De-icers for antenna arrays drawing over 24 amps will require two separate circuits, each with its own control box serving half the bays.

Table 2. Heater Leg Current Draw (amperes) and Recommended Control Box Models
Antenna Size 6602B 6600 High-Band 6600 Low-Band 6810 High-Band 6810 Low-Band Shively
Control Box
1-Bay
0.5 A
tbd
tbd
2.1 A
2.3 A
 Model 94068
10-amp,
single circuit
2-Bay
1.1
4.1
4.6
3-Bay
1.6
6.2
7.0
4-Bay
2.2
8.3
9.3
 Model 94068
20-amp,
single circuit
5-Bay
2.7
10.4
11.6
6-Bay
3.3
12.4
13.9
7-Bay
3.8
14.5
16.2
 Model 94068
30-amp,
single circuit
8-Bay
4.3
16.6
18.6
10-Bay
5.4
10.4
11.6
 Model 94068
20-amp,
each of 2 circuits
12-Bay
6.5
12.4
13.9
14-Bay
7.6
14.5
16.2
 Model 94068
30-amp,
each of 2 circuits
16-Bay
8.7
16.6
18.6
Antenna Size 6812B 6813
High-Band		 6813
Low-Band		 6814
High-Band		 6814
Low-Band		 Shively
Control Box
1-Bay
0.5 A
1.3 A
1.5 A
2.0 A
2.4 A
 Model 94068
10-amp,
single circuit
2-Bay
1.1
2.6
2.9
4.0
4.8
3-Bay
1.6
3.9
4.4
6.0
7.2
4-Bay
2.2
5.2
5.8
8.0
9.7
 Model 94068
20-amp,
single circuit
5-Bay
2.7
6.5
7.3
10.0
12.1
6-Bay
3.3
7.8
8.8
12.0
14.5
7-Bay
3.8
9.1
10.2
14.0
16.9
 Model 94068
30-amp,
single circuit
8-Bay
4.3
10.4
11.7
16.0
19.3
10-Bay
5.4
13.0
14.6
10.0
12.1
 Model 94068
20-amp,
each of 2 circuits
12-Bay
6.5
15.6
17.5
12.0
14.5
14-Bay
7.6
9.1
10.2
14.0
16.9
 Model 94068
30-amp,
each of 2 circuits
16-Bay
8.7
10.4
11.7
16.0
19.3
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Last updated: 06/10/08
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