Installation; Transfer Switch; Unpacking; Mounting - Generac Power Systems Stationary Emergency Generator Installation Manual

Installation

2.1

TRANSFER SWITCH

The generator system should be used in conjunction with a
matched automatic transfer switch. The NEMA 3R enclosure is
weather proof and can be used indoors or outdoors.
2.2

UNPACKING

Carefully unpack the transfer switch. Inspect closely for any dam-
age that might have occurred during shipment. The purchaser
must file with the carrier any claims for loss or damage incurred
while in transit.
Check that all packing material is completely removed from the
switch prior to installation.
Attach any lifting device to the transfer switch mounting holes or
brackets only. DO NOT LIFT THE SWITCH AT ANY OTHER POINT.
Always inspect the transfer switch for shipping damage.
2.3

MOUNTING

Mounting dimensions for the transfer switch enclosure can be
found in the transfer switch owner's manual. Enclosures are typi-
cally wall-mounted.
The transfer switch must be mounted vertically and must be level
and plumb.
Handle transfer switches carefully when install-

ing. Do not drop the switch. Protect the switch
against impact at all times, and against con-
struction grit and metal chips. Never install a
transfer switch that has been damaged.
Install the transfer switch as close as possible to the electrical
loads that are to be connected to it. Mount the switch vertically
to a rigid supporting structure. To prevent switch distortion, level
all mounting points. If necessary, use washers behind mounting
holes to level the unit. Never install the switch where water or any
corrosive substance might drip into the enclosure.
RTS and HTS switches are open transition switches. Because load
circuits can only be connected to one power supply at a time,
open transition switches prevent electrical feedback between utility
circuits and generator circuits (Figure 2.1).
Figure 2.1 — Connect Power Leads
16
3.1 BASIC STANDBY ELECTRIC
SYSTEM
Figure 3.1 shows a schematic diagram of a basic standby electric
system. Both the UTILITY power supply and the STANDBY (GEN-
ERATOR) output are connected to an approved transfer switch.
The transfer 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 3.1 – 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.
3.2 STANDBY 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 designated loads, within the wattage/
amperage capacity, during utility power outages, consider using
the emergency circuit isolation method.
Designated electrical loads are grouped together and wired into a
separate "Standby Distribution Panel." Load circuits powered by
that panel are within the wattage/amperage capacity of the genera-
tor 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 standby distribution panel circuit.
• Have it installed between the building's main distribution panel
and the standby distribution panel.