Mike Dolt Enterprises
Mike Dolt Enterprises
User: binwork91, Location: new york
Asked on: Wednesday, June 2, 2021 at 5:29 pm EDT
Answered on: Thursday, June 20, 2024 at 11:40 am EDT
Question: Hi, i am confuse with the motor OCPD.I want to verify if I make any mistake. see picture below. All of these are in the panelboard.I want to size the main fuse of this panelboard.So 477*1.75=834.75, next size up=1000A.1000+302+40+60+60+77+200+300=2039, next size down=2000A. so the main fuse for this panel is 2000A. am I correct?what about the load for this panel? I think we use load to size the panel, but for the motor, it is different.
Motor OCPD Verification
Your calculations for the motor OCPD appear to be correct.
Main Fuse Sizing Sum of the motor loads: 834.75A Fuse size for motor loads (next size up): 1000A Sum of the remaining loads: 1039A (302+40+60+60+77+200+300) Main fuse size (next size down): 2000ATherefore, the main fuse for this panelboard should be 2000A, which is correct.
Load Sizing of the Panel
For motor feeders, the panel load is determined by adding the full-load currents of all motors supplied by the feeder. This is because motors typically have high starting currents that can exceed the normal operating current.In your case, the load for this panel is 834.75A, which is the sum of the motor full-load currents. This load value is used to determine the minimum size of the panelboard based on its ampacity rating. Flag for review