This is the rear of the 2000 amp emergency transfer switch. The building load comes from the center group, the city power comes into the top group, and the diesel alternator feeds the bottom group. Imagine, each leg of the three phase power has twelve 500MCM copper cables to carry the current.

This is the main building power panel. The 8 five inch conduits coming out of the top go to the transfer switch.

Rear of main power panel.  The solid copper bus bars are 3/8 X 4 inches.

Preparing the foundation for the one megawatt diesel alternator. These are the conduits that go to the transfer switch