Project Scope for:
The Facts about the
This 1600 Amp Main Circuit Breaker tripped out on
It is known as Main #2.
This situation was not caused by "over-load" but
due to a hazardous condition when power is leaking to ground.
This circuit breaker tripped out twice:
Once during the electric storm and once during the process of turning the
building power back on (one breaker at a time).
In both cases Main #2 sensed a "ground-fault/power leak" and shut down.
These circuit breakers were affected by the interruption.
It is known as
ID Starting at the Top:
*Basement Mechanical Room
*2ND Floor Electrical Room.
*Generator System which is the bottom circuit breaker.
This breaker provides utility power to the Generator System and
is the beginning of the circuit which was found to have caused the original outage.
This breaker did not trip.
When turned on without any load, it tripped Main #2 (Photo A.) because it was
sensing "ground fault" somewhere in the circuit.
An unusual buzzing sound was heard at the same time.
Close-Up photo of the bottom circuit breaker
800 Amp, 480Volts
The power cables to the circuit exit the substation cabinet directly into the ground through
the concrete pad.
These cables travel below the ground to the building exterior wall.
They rise out of the ground and enter the building above the large Conference
Rooms, (note the two large conduits in the middle)
Close up of all power conduits entering the building above the large Conference
These conduits enter the Main Electrical Room in the Basement.
Conduits to the Automatic Transfer Switch "ATS".
They enter an intersecting splice box which combines the power cables for:
Inside the "ATS" intersecting splice box:
Generator Power conduits.
Generator Failed to Operate.
Loss of Power to Essential Circuits.
The UPS System batteries could not support the essential circuits for the length
of time without this Generator.