We have 3 chillers, 3 CHWP and 3 CDWP dedicated for office tower building load.

Chiller technical room is at roof floor.

When we run all CDWP, it is fine.

If we start running one CHWP, that is fine also.

But if we run 2 CHWP, one CHWP will make main circuit breaker get trip.

Note: breaker calibration is 150%[160A] higher than normal rated Amp.
- Cable line to each pump is fine, around 30 or 38 DegC
- During Breaker get trip, max rated Amp=80A
- CHWP- Chilled Water Pump
- CDWP- Condenser Water Pump

Could you kindly advice?
Does the surge pressure head cause on evaporator section can effect to motor overload?

Very thanks for your advice and comment.