Generac Power Systems Magnum Series Operating Manual page 38

Operation
When the generator is used as a standby power supply, it must be equipped with a transfer switch which isolates it
from the utility's distribution system. A transfer switch is designed to transfer electrical loads from the normal power
source (utility) to the emergency power source (generator) when normal voltage falls below a prescribed level. The
transfer switch automatically returns the load back to the normal source when power is restored back to operating
levels.
FAILURE TO ISOLATE THE GENERATOR FROM THE NORMAL POWER UTILITY CAN
CAUSE POTENTIALLY LETHAL VOLTAGE TO BACKFEED INTO THE UTILITY LINES.
THIS MAY RESULT IN INJURY OR ELECTROCUTION OF UTILITY WORKERS NEARBY.
MAKE SURE THE GENERATOR IS ISOLATED BY A TRANSFER SWITCH FROM ANY
LOCAL UTILITY LINES. THIS ALSO APPLIES IF THE GENERATOR IS BEING USED
Installation of a transfer switch or other type of remote starting device is the responsibility of the generator user.
Installation of such devices must be performed by following all directions supplied by the manufacturer of the switch.
If attaching the generator to a power supply normally serviced by a utility company, notify the utility company and
check state and local regulations. Familiarize yourself with all instructions and warning labels supplied with the switch.
Incoming
Utility
Power
Utility
Meter
Power From
Generator
ONLY a licensed electrician should perform wiring or related connections to the
generator. Installation should be in compliance with the National Electrical Code
(NEC), state and local regulations. Failure to follow these procedures could result in
property damage, personal injury or death. Before any connections are attempted,
verify the main circuit breaker and the Control Power switch are OFF (O) and that
the negative (-) battery cable has been disconnected from the engine starting battery.
When using the generator as a standby or substitute power supply, make sure the output
voltage and phase rotation of the generator match those of the local power utility. Improper
voltage or phase rotation may cause equipment damage or malfunction.
32
AS A BACKUP TO SOME OTHER TYPE OF POWER SUPPLY.
Distribution Panel
(Generator Power)
Distribution Panel
Transfer
Switch
Figure 3-10. Transfer Switch Operation
MMG130DI4/175DI4/205DI4 Operating Manual
DANGER
Emergency
Main
(Utility Power)
WARNING
WHITE = Incoming
Utility Power
GRAY = Normal Utility
Power Circuit
BLACK = Emergency
Generator Power Circuit
00206
33722 D