Voltage Selector Switch - Generac Power Systems Magnum MTT25 Operating Manual

IMPROPER OR INCORRECT CONNECTIONS TO A BUILDING'S ELECTRICAL SYSTEM
CAN CAUSE POTENTIALLY LETHAL VOLTAGE TO BACKFEED INTO UTILITY LINES.
THIS MAY RESULT IN INJURY OR ELECTROCUTION TO UTILITY WORKERS NEARBY.
MAKE SURE THE GENERATOR IS SUPPLYING POWER TO AN ISOLATED OBJECT
OR BUILDING THAT IS NOT CONNECTED TO ANY UTILITY LINES.
Connections to the lugs should be made by running the
power cables through the circular plastic bushing on the
lower right side of the control box. DO NOT make any
connections directly to the lugs without routing the cables
through this bushing. The lug door is equipped with safety
interlock switches that will automatically trip the main
circuit breaker and disable the voltage regulator when the
lug door is opened. Use a hex-wrench to tighten the cable
connections.
WARNING
Never attempt to disable or modify the
lug door safety switches. Equipment
damage, personal injury or death may
result.
A ground connection is located next to the connection
lugs. The unit MUST be connected to a good earthen
ground for proper operating safety. INSTALLATION
SHOULD BE IN COMPLIANCE WITH THE NATIONAL ELECTRICAL CODE (NEC), STATE AND LOCAL
REGULATIONS.

VOLTAGE SELECTOR SWITCH

The voltage selector switch mechanically changes the connections between the generator output leads and the
connection lugs on the main control panel. Voltage ranges are selected by rotating the handle on the switch to the
desired voltage.
NEVER change the voltage selector switch while the engine is running or the controller is
on. If the engine is running or starts while the setting is changed, severe arcing will occur
The voltage selector switch is equipped with a lockout mechanism. Once the proper voltage has been selected,
insert a padlock through the lockout hole(s). By locking the handle in place, unauthorized changing of the voltage
setting is prevented.
120/
208V
277/
480V
Switch styles vary by model.
= Not recommended for normal use
DANGER
causing damage to the switch and generator windings.
277/480V 3-PHASE
L1-L2 = 480V L1-N = 277V
L2-L3 = 480V L2-N = 277V
L3-L1 = 480V L3-N = 277V
VOLTAGES AT RECEPTACLES
RECEPTACLE
GFCI
GFCI w/Buck
Twist-locks
Tighten
Connection
Lugs with a
Hex Wrench
00134
N =
L-L L-N
- 139V
- 120V
240V 139V
00083
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