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2.1.2 OTHER PUBLISHED STANDARDS
In addition to NFPA standards, the following informa-
tion 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,
MAINTENANCE OF FARM STANDBY ELECTRIC
POWER, available from the American Society
of Agricultural Engineers, 2950 Niles Road, St.
Joseph, MI 49085.
• A52.1,
AMERICAN
FOR CHIMNEYS, FIREPLACES AND VENTING
SYSTEMS, available from the American National
Standard Institute, 1430 Broadway, N ew 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
connected to an approved transfer switch. The trans-
fer switch is required by electrical code and serves
the following functions:
• Allows 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.
8
Section 2 – Installation
Standby Generator Set
INSTALLATION
NATIONAL
STANDARD
The manufacturer recommends the use of a "GTS"
type transfer switch in conjunction with this gen-
erator.
2.3
EMERGENCY CIRCUIT ISOLATION
METHOD
This prevents overloading the generator by keeping
electrical loads below the wattage/amperage capac-
ity of the generator. If the generator is powering only
AND
critical loads, within the wattage/amperage capac-
ity, during utility power outages, 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 within the
wattage/amperage capacity of the generator set. When
this method is used, it is difficult to overload the gen-
erator. The transfer switch must meet the following
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.
2.4
TOTAL CIRCUIT ISOLATION
METHOD
When a generator capable of powering all electrical
loads in the circuit is to be installed, use the "Total
Circuit Isolation Method." It is possible for the gen-
erator to be overloaded when this isolation method is
employed. The following apply to the transfer switch
in this type of system.
• Ampere rating of the transfer switch must be equal
to, or greater than, the ampere rating of the normal
incoming utility service.
• The transfer switch is installed between the util-
ity service entrance and the building distribution
panel.
2.5
GROUNDING THE GENERATOR
The National Electrical Code requires the frame and
external electrically conductive parts of this equip-
ment to be properly connected to an approved earth
ground and/or grounding rods. For that purpose, a
GROUND LUG (Figure 2.2) is provided on the gen-
erator mounting base. Consult a qualified electrician
for grounding requirements in the area. Grounding
procedures must meet local regulations.
NOTE:
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