Consider the distribution system of a commercial building shown in the following diagram. Select the frames and trip ratings for all the power circuit breakers for the various panels and motors as well as the power circuit breaker at the secondary main feeder for the two options:

(a) The secondary transformer is rated at 480Y/277 V.

(b) The secondary transformer is rated at 208Y/120 V.

Assume that the available short-circuit currents are below 25,000 A throughout the entire electrical system.

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100000) (00000) CB1 CB2 100 kW 100 HP CB3 100 HP CB4 Lighting: pf=0.65 continuous Induction motor: n=85%, p=0.8 continuous Synchronous motor: 1-90%, p=0.9 continuous Receptacles: 50 kW pf 0.9 continuous Distribution system and electrical loads for a commercial building