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If you have 300KWh three phase 380 what is your panel board main crcuit breaker?

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April 22, 2008 1:06PM

I WILL ASSUME 300 IS POWER LOAD (POWER CONSUMPTION) NOT ENERGY CONSUMPTION: SIZING OF BREAKER DEPENDS ON WHAT TYPE OF LOADS UNDER THAT PANELBOARD --- A. SINGLE MOTOR B. TOTAL OF SEVERAL MOTORS C. LIGHTINGS / HEATERS / RESISTIVE LOADS ONLY D. COMBINATION OF ABOVE IN SIZING MAIN CIRCUIT BREAKER WE MUST CONSIDER LOAD CHARACTERISTICS FOR THE SAKE OF ENGINEERING AND ECONOMICS AS WELL. IN DEEPER DESIGN ANALYSIS WE MUST CONSIDER LOAD FLOW ANALYSIS, SHORT CIRCUIT LOAD CALCULATIONS, VOLTAGE DROP / DIP CONSIDERATIONS, MOTOR STARTING METHODS THAT WILL GREATLY AFFECT SELECTION OF BREAKERS AND NOT JUST MULTIPLYING BY THE USUAL --- 125% / 150% / 200% / 250% / 300% ETC., OF FULL LOAD CURRENTS. WE NEED TO CONSIDER ALSO THE LOCKED ROTOR CURRENTS; ARE ALL MOTORS RUNNING AT THE SAME TIME AND THE REALISTIC DEMAND FACTOR SHALL BE DEFINED.