Ib=450003⋅400⋅0.85=76.42 Acap I sub b equals the fraction with numerator 45000 and denominator the square root of 3 end-root center dot 400 center dot 0.85 end-fraction equals 76.42 A Step 2: Protective Device Selection Select a standard next-size circuit breaker: . Step 3: Corrected Current Capacity
Cable calculation is a multi-variable optimization process. It is not enough to simply match the amp rating to the load; the engineer must account for environmental stressors (heat, grouping) that degrade performance and physical constraints (length) that degrade efficiency. cable calculations
This is the current intended to be carried by the circuit in normal service. Ib=450003⋅400⋅0