Will Burt Night Scan Chief Series Operating Instructions Manual page 31

It is important to calculate the current draw for the wires in each lighting circuit. To calculate the
current draw for the wires:
• Divide the total watts of the entire mast unit by two (since there are two circuits).
• Divide the result by the voltage.
• This final result is the amperage required for each side light circuit.
Table 5-3 shows some example current calculations. Your mast may have different results based
on the installed light type and number of lights. In Example 1 (Table 5-3), the lights in the system
are a total of 500 watts. This is divided by two to get the watts per side. The result is then divided
by the voltage (12) to get the amps (21 rounded). The wires in this example should be able to
carry at least 21 amps with minimal voltage drop.
Table 5-3 Sample Light Circuit Current Draw Calculation
Total Watts
Example 1 500 W
Example 2 1500 W
It is the responsibility of the installer to provide over-current protection for both lighting circuits.
The over-current protection on each circuit should be sized for the calculated current draw for the
installed lights (and not based on wire size current capacity). It is also the responsibility of the
installer to provide a means to remove/isolate power from the mast light circuits and permit the
operator to follow proper lock-out tag-out procedures for maintenance or troubleshooting.
Light power cables can be purchased from The Will-Burt Company or provided by the installer.
For CE conformity, the installer must provide the light power cables in conformance with applica-
ble Directives. Cables supplied by The Will-Burt Company do not have blue color for conductor
identification.
If the cables are supplied by the installer, the cables must:
Condition #1: 120/240 VAC, 24 VDC and 12 VDC (with current ≤ 20 Amps per circuit)
• Be type SOOW or equivalent
• Be 10 AWG (or 6mm
• Have a maximum length for acceptable voltage drop of 70 feet (21 meters)
Condition #2: 12 VDC with current > 20 Amps per circuit using added solenoid
• Be type SOOW or equivalent
• Be 8 AWG (or 10mm
• Have a maximum length for acceptable voltage drop of 30 feet (9 meters)
For Condition #1 there are two inputs on the right side of the Base Board for attaching the light
power conductors.
5. Connect the light power to TB1 terminal block (RIGHT POWER) and TB2 terminal block
(LEFT POWER) following the polarity labeled on the Base Board. For AC lights, connect the
ground to the ground bar mounted on the base below the Base Board.
TP-4602001-T
DECEMBER 2020
Voltage
12 VDC
120 VAC
2
) conductors
2
) conductors or two pairs of 10 AWG (6mm
OPERATING INSTRUCTIONS
Current Draw Per Side (Amps)
21 Amps per side
6.25 Amps per side
2
)
NIGHT SCAN CHIEF
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