muhasarr
Member
- Location
- United States
If I have three 25hp motors ( two running and one standby) plus a 5hp motor located in one control panel which is fed from an MCC, how do I size the main breaker and conductor from the MCC to the control panel?
Below are my calculations but I have a feeling it is not correct. Help needed.
1- FLA for largest pump(25HP) is 34A
2-FLA for 5HP pump is 7.6A
3- So my main circuit breaker= 2.5(3.4A) + 7.6A = 92.6A (So my breaker size is 100A)
4- Solving for conductor: 125%(34A) + 7.6A= 50.1 (According to NEC 310.15(b)(16), the conductor should be a #AWG)
Am I missing anything in my calculations?
Below are my calculations but I have a feeling it is not correct. Help needed.
1- FLA for largest pump(25HP) is 34A
2-FLA for 5HP pump is 7.6A
3- So my main circuit breaker= 2.5(3.4A) + 7.6A = 92.6A (So my breaker size is 100A)
4- Solving for conductor: 125%(34A) + 7.6A= 50.1 (According to NEC 310.15(b)(16), the conductor should be a #AWG)
Am I missing anything in my calculations?