How to choose an input circuit breaker and cable with a load of 88 kW?
There is a total load power of 88 kW. Of these, 48 kW is a three-phase connection, and 40 kW is a single-phase evenly distributed over all phases. How to choose the input circuit breaker and cable?
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In this case, it all depends on which circuit the three-phase load is connected to. If the three-phase load is turned on according to the star scheme, then the current in one phase is 73 A + 61 A, the current is a single-phase load in the phase. Total - 134 A. Choose the nearest larger denomination that is presented by the manufacturer of the circuit breaker. The cross section of the copper cable for a given current is 50 square meters. mm If the three-phase load is switched on according to the triangle scheme, the current in one phase is 42 A +61 A the current of a single-phase load in phase. Total - 103 A. Also choose the nearest larger denomination of the machine. In this case, the cross-section of the copper cable is 35 square meters. mm
But you also need to take into account the nature of the load and the length of the lines - there is no answer in a nutshell, when designing electrical installations, all the nuances must be taken into account.