Generac Mobile MGG450, Owner'S Manual

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Owner’s Manual for MGG450 19
Operation
external loads to the generator.
Connections to the bus bars should be made by running
the power cables up through the opening in the bottom of
the box. Do not make any connections directly to the bus
bars without routing the cables through the slot.
The door is equipped with a safety interlock switch that
will trip the main circuit breaker and disable the voltage
regulator if the door is opened while the unit is operating.
A ground connection is included. The generator neutral is
bonded to ground when it is shipped from the factory.
The bonding plate may need to be removed if the unit is
used as a standby power source.
IMPORTANT NOTE: Installation should be in
compliance with the national electrical code (NEC),
state and local regulations.
A
B
001440
Figure 3-2. Generator Output Connections
A Bus bars
B Grounding lug
Customer Convenience Receptacles
The unit is equipped with two 120VAC Ground Fault
Circuit Interrupt (GFCI) receptacles, located inside the
double doors on the right side of the unit. These
receptacles are not routed through the main circuit
breaker. Power is available any time the generator is
running.
Main Circuit Breaker
The main circuit breaker is located to the right of the
control panel. When the breaker is in the open (O)
position, power is interrupted between the bus
connections and the generator. The input receptacles will
continue to receive power, even when the main circuit
breaker is open.
Once connections have been made to the bus bars and
the generator has been started and allowed to reach
normal operating conditions, pushing the “Open/Close
Breaker” button on the controller will switch the main
circuit breaker CLOSE.
IMPORTANT NOTE: Do not use the buttons on the
main circuit breaker to open or close the breaker.
Only use the buttons on the controller. If the circuit
breaker buttons are pressed, the unit will shutdown
immediately. It is especially important to only use the
controller when operating in a parallel configuration,
as the controller will determine when the breaker can
be opened and closed based on generator phase
rotation and load levels.
The main circuit breaker will be tripped, disconnecting
power to the bus connections, if any of the following
conditions occur while the unit is running:
• Overload of the generator circuits to the bus
connections. At 105% load, there will be an audible
warning. At 110% load, the breaker opens and
power will be disconnected.
• The customer connection box door is opened.
• If the emergency stop switch is activated.
Verify any problems that cause the main circuit breaker to
trip are corrected before returning the switch to the
CLOSE (I) position.
Circuit Breaker Box
The circuit breaker box is located on the right side of the
unit. It contains five 20A breakers and two 15A breakers
for unit equipment, relays, and GFCI receptacles.
001439
Figure 3-3. Circuit Breaker Box
Frame Ground Connection
The NEC may require that the frame and exposed metal
surfaces be at local ground reference potential to avoid
electrical shock hazard. A local ground reference may
require a driven earth ground conductor at the unit
installation site. Make the ground connection to the
ground lug located on the outside of the frame. Use the
appropriate size wire as required by the NEC and local
regulations.
Determine ground stud location and connect the ground
wire to the “earth ground” terminal. This ground is the
local reference ground to ground the unit frame only.