8
Generac
®
Power Systems, Inc.
Section 2 – Installation
Generac Standby Generator Sets
NOTE:
For more information about the installation of a
standby system, you can order
Engine-Generator
Standby Electric Power Systems Installer’s
Guide and Reference Manual (part #46622
) from
your Generac Authorized Service Dealer.
2.1.1 NFPA STANDARDS
The following published standards booklets pertain-
ing to standby electric systems are available form the
National Fire Protection Association (NFPA),
Batterymarch Park, Quincy, MA 02269:
• NFPA No. 37, STATIONARY COMBUSTION
ENGINES AND GAS TURBINES.
• NFPA No. 76A, ESSENTIAL ELECTRICAL SYS-
TEMS FOR HEALTH CARE FACILITIES.
• NFPA No. 220, STANDARD TYPES OF BUILDING
CONSTRUCTION
• NFPA No. 68, GUIDE FOR EXPLOSION VENTING
• NFPA No. 70, NATIONAL ELECTRICAL CODE.
• NFPA No. 30, FLAMMABLE AND COMBUSTIBLE
LIQUIDS CODE.
• NFPA No. 10, INSTALLATION, MAINTENANCE AND
USE OF PORTABLE FIRE EXTINGUISHERS.
2.1.2 OTHER PUBLISHED STANDARDS
In addition to NFPA standards, the following infor-
mation pertaining to the installation and use of
standby electric systems is available:
• Article X, NATIONAL BUILDING CODE, available
from the American Insurance Association, 85 John
Street, New York, N.Y. 10038.
• AGRICULTURAL WIRING HANDBOOK, obtainable
from the Food and Energy Council, 909 University
Avenue, Columbia, MO, 65201.
• ASAE EP-364.2, INSTALLATION AND MAINTE-
NANCE OF FARM STANDBY ELECTRIC POWER,
available from the American Society of Agricultural
Engineers, 2950 Niles Road, St. Joseph, MI 49085.
• A52.1, AMERICAN NATIONAL STANDARD FOR
CHIMNEYS, FIREPLACES AND VENTING SYS-
TEMS, available from the American National
Standard Institute, 1430 Broadway, New York, N.Y.
10018.
2.2
BASIC STANDBY ELECTRIC
SYSTEM
Figure 2.1 shows a schematic diagram of a basic
standby electric system. Both the UTILITY power
supply and the STANDBY (generator) output are con-
nected to an approved transfer switch. The transfer
switch is required by electrical code and serves the
following functions:
• Permits the LOAD circuits to be connected to only
one power supply at a time.
• Prevents electrical backfeed between the generator
and the UTILITY power circuits.
Figure 2.1 – Basic Standby Electric System
Notice that both the STANDBY and the UTILITY
power supplies to the transfer switch are protected
against overload by a main line circuit breaker.
NOTE:
Generac recommends the use of a Generac power
systems “GTS” type transfer switch in conjunction
with this generator.
2.3
EMERGENCY CIRCUIT ISOLATION
METHOD
This prevents overloading the generator by keeping
electrical loads below the wattage/amperage capacity
of the generator. If the generator is powering only crit-
ical loads, within the wattage/amperage capacity, dur-
ing utility power outages, you might consider using
the emergency circuit isolation method.
Critical electrical loads are grouped together and
wired into a separate “Emergency Distribution
Panel.” Load circuits powered by that panel are with-
in the wattage/amperage capacity of the generator set.
When this method is used, it is difficult to overload
the generator. The transfer switch must meet the fol-
lowing requirements:
• It must have an ampere rating equal to the total
amperage rating of the emergency distribution
panel circuit.
• Have it installed between the building’s main dis-
tribution panel and the emergency distribution
panel.
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