Emergency Circuit Isolation Method; Total Circuit Isolation Method; Grounding The Generator; Generator Ac Neutral Connections - Generac Power Systems 004721-0, 004722-0, 004723-0, 004724-0, 004725-0, 004725-1, 004725-2, 004725-3, 004726-0 Owner's Manual

Generac recommends the use of a Generac Power
Systems "GTS" type transfer switch in conjunc-
tion with this generator.
2.5 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, consider using the emer-
gency 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, or greater
than, 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.
2.6 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 gener-
ator 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 utility
service entrance and the building distribution
panel.
2.7

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 gener-
ator mounting base. Consult a qualified electrician
for grounding requirements in the area. Grounding
procedures must meet local regulations.
10 Generac ® Power Systems, Inc.
Section 2 — Installation
Guardian Liquid-cooled 15 kW, 20 kW and 25 kW Generators
NOTE:
DANGER
Do not connect the ground wire to any pipe
that carries a flammable or explosive substance
– FIRE or an EXPLOSION may result.
Proper grounding helps protect personnel against
electrical shock in the event of a ground fault condi-
tion in the generator or in connected electrical
devices. In addition, grounding helps dissipate static
electricity that often builds up in ungrounded
devices.
Figure 2.2 – Generator Grounding Lug (typical)
2.8 GENERATOR AC NEUTRAL
CONNECTIONS
Generac Power Systems uses an UNGROUNDED AC
neutral. Grounding is recommended only at the main
service entrance. If the neutral wire is grounded and
one of the phase loads becomes grounded, the exces-
sive current opens the load circuit breaker or col-
lapses the generator field. The actual result depends
on the electrical characteristics of the particular
installed generator.
2.9 TRANSFER SWITCH START SIGNAL
CONNECTIONS
If the generator is to be installed with an automatic
transfer switch, such as a Generac GTS-type switch,
it is necessary to connect the two-wire start
control system.
Connect the two-wire start signal from the automatic
transfer switch to the automatic start connection,
which is located in the right hand corner inside the
control panel. Match wires 178 and 183 in the trans-
fer switch to 178 and 183 on the terminal strip in the
control panel. The conductors for the two-wire start
circuit must be in their own conduit.