Jetson
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To size a field supplied distribution panel for an array of chillers, use the following steps.
1. The Max Fuse or Maximum Overcurrent Protection Device (MOCP) of the electrical
distribution panel is as follows:
a. First, calculate the MOCP of each individual chiller. MOCP = 2.25 (Largest RLA) +
Sum of the other RLAs. Sum the MOCPs of each individual chiller. This is the MOCP
of the electrical distribution panel associated with this bank of chillers. Select the next
size down fuse from this value.
b. Standard Ampere Ratings for Fuses (From NEC Handbook, 240-6)
The standard ratings for fuses shall be considered 15, 20, 25, 30, 35, 40, 45, 50, 60, 70,
80, 90, 100, 110, 125, 150, 175, 200, 225, 250, 300, 350, 400, 450, 500, 600, 700, 800,
1000, 1200, 1600, 2000, 2500, 3000 and 4000 amperes.
2. The recommended fuse size in amps (RFA) is calculated as follows:
a. RFA = 1.75* (largest RLA) + (Smallest RLA) for the given bank of chillers.
3. The MCA of the electrical distribution panel is calculated as follows:
a. Sum the MCAs of each individual chiller from the preceding table. This is the MCA of
the electrical distribution panel associated with this bank of chillers.
4. Wiring for main field supply must be rated 75 C.
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