Kohler RXT Operation And Installation

Operation and

Installation

Automatic Transfer Switch

Model:

RXT

100--400 Amp Automatic Transfer Switches

For use with Kohlerr Model RESA, RESAL, or RCL generator sets

equipped with RDC2 or DC2 generator/transfer switch controllers

TP-6807 12/11

Product Identification Information

Product identification numbers determine service parts.
Record the product identification numbers in the spaces
below immediately after unpacking the products so that
the numbers are readily available for future reference.
Record field-installed kit numbers after installing the
kits.

Transfer Switch Identification Numbers

Record the product identification numbers from the
transfer switch nameplate.

Model Designation

Serial Number

TP-6807 12/112

Table of Contents

Product Identification Information 2............................................................

Safety Precautions and Instructions 5........................................................

Introduction 7...............................................................................

Nameplate 8.................................................................

Model Designation 8..........................................................

Service Assistance 9........................................................................

Section 1 Description 11.....................................................................

1.1 Transfer Switch Description 11.............................................

1.2 Service Entrance Models 11...............................................

1.3 Load Centers 11.........................................................

1.4 Controller Interface Board 12..............................................

1.5 Optional LED Indicator Panel 12...........................................

Section 2 Installation 13......................................................................

2.1 Introduction 13..........................................................

2.2 Receipt of Unit 13........................................................

2.2.1 Inspection 13....................................................

2.2.2 Storage 13......................................................

2.2.3 Unpacking 13....................................................

2.2.4 Lifting 13........................................................

2.3 Installation 14...........................................................

2.4 Manual Operation Check 15...............................................

2.4.1 Manual Operation Procedure 1 15..................................

2.4.2 Manual Operation Procedure 2 15..................................

2.5 Electrical Wiring 16.......................................................

2.5.1 Load Center Circuit Breakers 16...................................

2.5.2 AC Power Connections 17........................................

2.5.3 Neutral Connection 18............................................

2.5.4 Neutral Bonding Jumper, Service Entrance Models 18................

2.5.5 Engine Start Function 18..........................................

2.5.6 Interface Module Connection 19....................................

2.5.7 Optional Load Control Connection 20...............................

2.5.8 Accessory Module Connections 20.................................

2.6 Test and Exercise 20.....................................................

2.7 Warranty Registration 20..................................................

Section 3 Operation 21.......................................................................

3.1 Model RXT Transfer Switch Operation 21...................................

3.2 Source Availability 21.....................................................

3.3 ATS Control Sequence of Operation 21.....................................

3.4 Time Delays 22..........................................................

3.5 Load Control Time Delay 22...............................................

Section 4 Service Disconnect, SE Model 23....................................................

4.1 Service Disconnect Procedure 23..........................................

4.2 Source Circuit Breaker Reset 23...........................................

Section 5 Scheduled Maintenance 25..........................................................

5.1 Introduction 25..........................................................

5.2 Testing 26..............................................................

5.2.1 Weekly Generator Set Exercise 26.................................

5.2.2 Monthly Automatic Control System Test 26..........................

TP-6807 12/11 Table of Contents 3

Table of Contents, continued

5.3 Inspection and Service 26.................................................

5.3.1 General Inspection 26............................................

5.3.2 Other Inspections and Service 27..................................

5.4 Service Schedule 27.....................................................

Section 6 Diagrams and Drawings 29..........................................................

Appendix A Abbreviations 55..................................................................

TP-6807 12/11Table of Contents4

Safety Precautions and Instructions

IMPORTANT SAFETY INSTRUCTIONS.

Electromechanical equipment,
including generator sets, transfer
switches, switchgear, and accessories,
can cause bodily harm and pose
life-threatening danger when
improperly installed, operated, or
maintained. To prevent accidents be
aware of potential dangers and act
safely. Read and follow all safety
precautions and instructions. SAVE
THESE INSTRUCTIONS.

This manual has several types of safety
precautions and instructions: Danger,
Warning, Caution, and Notice.

DANGER

Danger indicates the presence of a
hazard that will cause severe

personal injury, death,or
substantial property damage.

WARNING

Warning indicates the presence of a
hazard that can cause severe

personal injury, death, or
substantial property damage.

CAUTION

Caution indicates the presence of a
hazard that will or can cause minor
personal injury or property damage.

NOTICE

Notice communicates installation,
operation, or maintenance information
that is safety related but not hazard
related.

Safety decals affixed to the equipment
in prominent places alert the operator
or service technician to potential
hazards and explain how to act safely.
The decals are shown throughout this
publication to improve operator
recognition. Replace missing or
damaged decals.

Accidental Starting

WARNING

Accidental starting.
Can cause severe injury or death.

Disconnect the battery cables before
working on the generator set.
Remove the negative (--) lead first
when disconnecting the battery.
Reconnect the negative (--) lead last
when reconnecting the battery.

Disabling the generator set.
Accidental starting can cause
severe injury or death. Before

working on the generator set or
connected equipment, disable the
generator set as follows: (1) Move the
generator set master switch to the OFF
position. (2) Disconnect the power to
the battery charger. (3) Remove the
battery cables, negative (--) lead first.
Reconnect the negative (--) lead last
when reconnecting the battery. Follow
these precautions to prevent starting of
the generator set by an automatic
transfer switch, remote start/stop
switch, or engine start command from a
remote computer.

Hazardous Voltage/
Moving Parts

DANGER

Hazardous voltage.
Will cause severe injury or death.

Disconnect all power sources before
opening the enclosure.

DANGER

Hazardous voltage.
Will cause severe injury or death.

Only authorized personnel should
open the enclosure.

DANGER

Hazardous voltage.
Will cause severe injury or death.

This equipment must be installed and
serviced by qualified electrical
personnel.

Grounding electrical equipment.
Hazardous voltage can cause
severe injury or death. Electrocution

is possible whenever electricity is
present. Ensure you comply with all
applicable codes and standards.
Electrically ground the generator set,
transfer switch, and related equipment
and electrical circuits. Turn off the main
circuit breakers of all power sources
before servicing the equipment. Never
contact electrical leads or appliances
when standing in water or on wet
ground because these conditions
increase the risk of electrocution.

Short circuits. Hazardous
voltage/current can cause severe
injury or death. Short circuits can

cause bodily injury and/or equipment
damage. Do not contact electrical
connections with tools or jewelry while
making adjustments or repairs.
Remove all jewelry before servicing the
equipment.

Making line or auxiliary
connections. Hazardous voltage
can cause severe injury or death. To

prevent electrical shock deenergize the
normal power source before making
any line or auxiliary connections.

TP-6807 12/11 5Safety Precautions and Instructions

Servicing the transfer switch.
Hazardous voltage can cause
severe injury or death. Deenergizeall

power sources before servicing. Turn
off the main circuit breakers of all
transfer switch power sources and
disable all generator sets as follows:
(1) Move all generator set master
controller switches to the OFF position.
(2) Disconnect power to all battery
chargers. (3) Disconnect all battery
cables, negative (--) leads first.
Reconnect negative (--) leads last when
reconnecting the battery cables after
servicing. Follow these precautions to
prevent the starting of generator sets
by an automatic transfer switch, remote
start/stop switch, or engine start
command from a remote computer.
Before servicing any components
inside the enclosure: (1) Remove all
jewelry. (2) Stand on a dry, approved
electrically insulated mat. (3) Test
circuits with a voltmeter to verify that
they are deenergized.

Heavy Equipment

WARNING

Unbalanced weight.
Improper lifting can cause severe
injury or death and equipment
damage.

Use adequate lifting capacity.
Never leave the transfer switch
standing upright unless it is securely
bolted in place or stabilized.

Notice

NOTICE

Foreign material contamination.

Cover the transfer switch during
installation to keep dirt, grit, metal drill
chips, and other debris out of the
components. Cover the solenoid
mechanism during installation. After
installation, use the manual operating
handle to cycle the contactor to verify
that it operates freely. Do not use a
screwdriver to force the contactor
mechanism.

NOTICE

Electrostatic discharge damage.

Electrostatic discharge (ESD)
damages electronic circuit boards.
Prevent electrostatic discharge
damage by wearing an approved
grounding wrist strap when handling
electronic circuit boards or integrated
circuits. An approved grounding wrist
strap provides a high resistance (about
1 megohm), not a direct short,to
ground.

TP-6807 12/116 Safety Precautions and Instructions

This manual provides operation and installation
instructions for Kohlerr Model RXT automatic transfer
switches. See Figure 1 for typical Model RXT transfer
switches.

Model RXT transfer switches operate only with Kohlerr
Model generator sets equipped with the RDC2 or DC2
generator/transfer switch controller. See Figure 2 for
controller identification. The following Kohlerr model
generator sets can be used with the Model RXT transfer
switch:

D 14RESA

D 14RESAL

D 20RESA

D 20RESAL

D 48RCL

Information in this publication represents data available
at the time of print. Kohler Co. reserves the right to
change this literature and the products represented
without notice and without any obligation or liability
whatsoever.

Introduction

Read this manual and carefully follow all procedures
and safety precautions to ensure proper equipment
operation and to avoid bodily injury. Read and follow the
Safety Precautions and Instructions section at the
beginning of this manual. Keep this manual with the
equipment for future reference.

The equipment service requirements are very important
to safe and efficient operation. Inspect parts often and
perform required service at the prescribed intervals.
Obtain service from an authorized service distributor/
dealer to keep equipment in top condition.

Figure 1 Typical Model RXT Transfer Switches

(shown with optional status indicators)

RDC2 DC2

GM77569

Figure 2 RDC2 and DC2 Generator/Transfer Switch

Controllers (provided with and mounted on
the generator set)

TP-6807 12/11 7Introduction

Nameplate

n

A nameplate attached to the inside of the enclosure
cover or on the upper right side wall includes a model
designation, a serial number, ratings, and other
information about the transfer switch. See Figure 3.

Check the transfer switch model number from the
transfer switch nameplate and verify that it matches the
model shown on the front cover of this manual before
proceeding with installation.

TRANSFER SWITCH

FOR EMERGENCY SYSTEMS

VOLTS
PHASE
HERTZ

TYPE ENCLOSURE

MFG. DATE

ACCESSORIES:

1

MATERIAL
MODEL

2

SERIAL NO.

AMPS
WIRES
POLES

BAR CODE

3

Copy the model designation, serial number, and
accessory information from the nameplate to the spaces
provided in the Product Identification Information
section located inside the front cover of this manual for
use when requesting service or parts.

1. Model designation

2. Serial number

3. Factory-installed accessory numbers

LISTED

R

TRANSFER SWITCH

FOR EMERGENCY SYSTEMS

GM21291-E

Figure 3 Typical Transfer Switch Nameplate

Model Designation

Figure 4 explains the model designation.

Model Controls Voltage Poles Enclosure Current Rating Connections

Record the transfer switch model designation in the boxes. The transfer switch model designation defines ratings a
characteristics as explained below.

Sample Model Designation: RXT-JFNC-0200A

Model

RXT: Kohler Automatic Transfer Switch

Controls

J: Interface for RDC2/DC2 Controller

Voltage/Frequency

C: 208 Volts/60 Hz (3-phase only)
F: 240 Volts/60 Hz
M: 480 Volts/60 Hz (3-phase only)

Number of Poles/Wires

N: 2-pole, 3-wire, solid neutral (120/240 V only)
T: 3-pole, 4-wire, solid neutral
V: 4-pole, 4-wire, switched neutral

Enclosure

C: NEMA 3R

Current Rating: Numbers indicate the current rating
of the switch in amperes:

0100
0200
0400

Connections

A: No load center
B: With load center (100 amp single-phase only)
ASE: Service entrance rated

Figure 4 Model Designation

TP-6807 12/118 Introduction

Service Assistance

For professional advice on generator set power
requirements and conscientious service, please contact
your nearest Kohler distributor or dealer.

D Consult the Yellow Pages under the heading

Generators—Electric.

D Visit the Kohler Power Systems website at

KohlerPower.com.

D Look at the labels and stickers on your Kohler product

or review the appropriate literature or documents
included with the product.

D Call toll free in the US and Canada 1-800-544-2444.

D Outside the US and Canada, call the nearest regional

office.

Headquarters Europe, Middle East, Africa
(EMEA)

Kohler Power Systems
3 rue de Brennus
93200 Saint Denis
France
Phone: [phone]
Fax: [phone]

Asia Pacific

Power Systems Asia Pacific Regional Office
Singapore, Republic of Singapore
Phone: [phone]
Fax: [phone]

China

North China Regional Office, Beijing
Phone: [phone]

(86) 10 6518 7951
(86) 10 6518 7952

Fax: [phone]

East China Regional Office, Shanghai
Phone: [phone]
Fax: [phone]

India, Bangladesh, Sri Lanka

India Regional Office
Bangalore, India
Phone: [phone]

(91) 80 3366231

Fax: [phone]

Japan, Korea

North Asia Regional Office
Tokyo, Japan
Phone: [phone]
Fax: [phone]

Latin America

Latin America Regional Office
Lakeland, Florida, USA
Phone: [phone]
Fax: [phone]

TP-6807 12/11 9Service Assistance

Notes

TP-6807 12/1110 Service Assistance

Section 1 Description

1.1 Transfer Switch Description

An automatic transfer switch (ATS) transfers electrical
loads from a normal source of electrical power to an
emergency source when the normal source voltage or
frequency falls below an acceptable level. The normal
source is typically utility power. The emergency source
is usually a generator set.

Model RXT transfer switches must be connected to a
generator set equipped with the Kohlerr RDC2 or DC2
generator/transfer switch controller. Applicable
generator set models are listed in the Introduction.

Voltage sensing data from the ATS is continuously
transmitted to the RDC2/DC2 controller mounted on the
generator set. When the normal source fails, the
RDC2/DC2 controller signals the emergency source
generator set to start. When the emergency source
reaches acceptable levels and stabilizes, the ATS
transfers the electrical load to the emergency source.

The RDC2/DC2 controller signals the ATS to transfer
the load back when the normal source returns and
stabilizes.

Service Entrance Model

Figure 1-1 shows a typical installation block diagram.

Emergency
(Generator)

Normal
(Utility)

Power
Switching
Device

Power

Power

Automatic T ransfer Switch

To Load

Generator

Electrical

Controls

Interface

Board

TP-6751

Figure 1-1 Typical ATS Block Diagram

Load Center Model Standard Model

Figure 1-2 Selected Transfer Switches

(covers removed)

1.2 Service Entrance Models

Service entrance models use a circuit breaker to provide
the service disconnect for the utility source. A service
entrance model is shown in Figure 1-2.

1.3 Load Centers

Model RXT 100 amp transfer switches are available with
a built-in load center. A model with a built-in load center
is shown in Figure 1-2. Models without load centers
require the installation of a separate load panel.

TP-6807 12/11 11Section 1 Description

Loads. The transfer switch can be connected to supply
all of the electrical loads in the home, or only the
essential loads such as the furnace, refrigerator, well
pump, and selected light circuits. Identify the essential
circuits that must be supplied during a power outage.
Verify that the generator set and transfer switch are
adequately rated to supply all of the selected loads.

Circuit breakers. Because the size and number of
circuit breakers required will vary with each application,
circuit breakers are not provided with the transfer switch
load center.

Determine the circuits that will be connected to the
transfer switch (essential loads). Identify the breakers
for those circuits in the main distribution panel.

The ATS load center requires Square D type QO
breakers. If the main distribution panel uses the same
type of breakers, the breakers can be moved from the
main panel to the load center. Otherwise, obtain new
Square D type QO circuit breakers. For each circuit, the
rating of the load center circuit breaker must match the
rating of the existing breaker in the main panel.

1.5 Optional LED Indicator Panel

A user interface panel that contains status-indicating
LEDs is available. See Figure 1-3. Source available
LEDs light to indicate that the utility and/or generator
sources are available. The utility or generator source
supplying load LED lights to show which source is
connected to the building load (i.e. contactor position,
normal or emergency).

If the status indicator is purchased as a loose kit (not
factory-installed), refer to the installation instructions
provided with the kit, TT-1585.

1

2

Up to 8 tandem breakers can be used. Use Square D
type QOT tandem breakers.

Verify that the total rating for all of the breakers used in
the load center does not exceed the rating of the transfer
switch.

1.4 Controller Interface Board

All ATS control functions are performed by the
RDC2/DC2 controller mounted on the generator set and
communicated through the interface board. The
controller interface board sends voltage sensing data to
the RDC2/DC2 controller and receives transfer and load
control signals from the RDC2/DC2 controller.

3

4

1. Utility power available

2. Utility source supplying load

3. Generator source supplying load

4. Generator power available

Figure 1-3 LED Indicators

GM78649

TP-6807 12/1112 Section 1 Description

Section 2 Installation

2.1 Introduction

Kohlerr transfer switches are shipped factory-wired,
factory-tested, and ready for installation. Have the
equipment installed only by trained and qualified
personnel, and verify that the installation complies with
applicable codes and standards. Protect the switch
against damage before and during installation.

2.2 Receipt of Unit

2.2.1 Inspection

At the time of delivery, inspect the packaging and the
transfer switch for signs of shipping damage. Unpack
the transfer switch as soon as possible and inspect the
exterior and interior for shipping damage. If damage
and/or rough handling is evident, immediately file a
damage claim with the transportation company.

2.2.2 Storage

Store the transfer switch in its protective packing until
final installation. Protect the transfer switch at all times
from moisture, construction grit, and metal chips. Avoid
storage in cold or damp areas where moisture could
condense on the unit. See Figure 2-1 for acceptable
storage temperatures.

Item Specification

Storage
Temperature

Operating
Temperature

Humidity 5% to 95% noncondensing

Altitude 0 to 3050 m (10000 ft.) without derating

Figure 2-1 Environmental Specifications

2.2.3 Unpacking

Allow the equipment to warm to room temperature for at
least 24 hours before unpacking to prevent
condensation on the electrical apparatus. Use care
when unpacking to avoid damaging transfer switch
components. Use a vacuum cleaner or a dry cloth to
remove dirt and packing material that may have

-- 4 0 °Cto85°C(--40°F to 185°F)

-- 2 0 °Cto70°C(--4°F to 158°F)

accumulated in the transfer switch or any of its
components.

Note: Do not use compressed air to clean the switch.

Cleaning with compressed air can cause debris
to lodge in the components and damage the
switch.

2.2.4 Lifting

WARNING

Unbalanced weight.
Improper lifting can cause severe
injury or death and equipment
damage.

Use adequate lifting capacity.
Never leave the transfer switch
standing upright unless it is securely
bolted in place or stabilized.

See Figure 2-2 or the dimensional drawing for the
weight of the transfer switch. Use a spreader bar to lift
the transfer switch. Attach the bar only to the
enclosure’s mounting holes or lifting brackets; do not lift
the unit any other way. Close and latch the enclosure
door before moving the unit.

Amps Description

Single phase 7 (14)

100

200

400

With load center 8.2 (18)

Three phase 14 (30)

Service Entrance 10 (22)

Single phase 7 (15)

Three phase 14 (30)

Service Entrance 12 (26)

Single phase 36 (80)

3-Pole/208--240 Volts 41 (90)

3-Pole/480 Volts 59 (130)

4-Pole 59 (130)

Service Entrance 46 (100)

Figure 2-2 Approximate Weights

Weight, kg (lb.) [

TP-6807 12/11 13Section 2 Installation

2.3 Installation

NOTICE

Foreign material contamination. Cover the transfer switch
during installation to keep dirt, grit, metal drill chips, and other
debris out of the components. Cover the solenoid mechanism
during installation. Afterinstallation, use the manual operating
handle to cycle the contactor to verify that it operates freely.
Do not use a screwdriver to force the contactor mechanism.

NOTICE

Hardware damage. The transfer switch may use both
American Standard and metric hardware. Use the correct size
tools to prevent rounding of the bolt heads and nuts.

Check the system voltage and frequency. Compare
the voltage and frequency shown on the transfer switch
nameplate to the source voltage and frequency. Do not
install the transfer switch if the voltage and frequency
are different from the normal (utility) source voltage and
frequency or the emergency source voltage and
frequency shown on the generator set nameplate.

Plan the installation. Use the dimensions given on the
enclosure dimension (ADV) drawings in Section 6.
Select a mounting site that complies with local electrical
code restrictions for the enclosure type. Mount the
transfer switch as close to the load and power sources
as possible. Allow adequate space to open the
enclosure and service the switch.

Pull the bottom of the panel out and down until the top
clears the enclosure. Remove the inner panel to access
the transfer switch components.

NEMA 3R enclosures have locking tabs at the bottom of
the enclosure and the door. Whilethe enclosure is open,
turn the locking tab out so that the door can be locked
with a padlock after installation is complete.

Wall mounting. Mount the transfer switch to a wall or
other rigid vertical supporting structure. Refer to the
dimension drawings in Section 6 for hole locations. Use
shims to plumb the enclosure.

Cover or remove the transfer switch’s internal
components to protect them from drill chips or debris
during installation. Use a vacuum cleaner to remove
debris from the enclosure.

Note: Do not use compressed air to clean the switch.

Cleaning with compressed air can cause debris
to lodge in the components and cause damage.

Tighten the mounting screws to 2.9 Nm (26 in. lb.) when
reinstalling the components.

Clearance holes through the back of each enclosure are
provided for mounting. The mounting holes on NEMA
3R enclosures have gaskets to seal out moisture. Use
washers with the mounting screws to protect the
gaskets.

NEMA 3R enclosures. To remove the enclosure’s front
panel, support the panel while removing the screws.

TP-6807 12/1114 Section 2 Installation

2.4 Manual Operation Check

DANGER

CN

3

4

C

NO

NL1

NC

SCN

NL2

Hazardous voltage.
Will cause severe injury or death.

Disconnect all power sources before
opening the enclosure.

Check the manual operation before energizing the
transfer switch. Verify that the contactor operates
smoothly without binding. Do not place the transfer
switch into service if the contactor does not operate
smoothly.

After checking the manual operation, place the
contactor in the Normal (utility) position.

See Figure 2-3 to identify the manual operation
procedure for your transfer switch.

ATS Procedure Figure

100--200 amps, 1-phase 2.4.1 Figure 2-4

100--200 amps, 3-phase 2.4.2 Figure 2-6

400 amps, 1-phase 2.4.1 Figure 2-5

400 amps, 3-phase, 3-pole,
208--240 Volts

400 amps, 3-phase,
3-pole/480 Volt and 4-pole

2.4.1 Figure 2-5

2.4.2 Figure 2-7

Figure 2-3 Manual Operation Procedure Guide

2.4.1 Manual Operation Procedure 1

Note: Never manually operate the transfer switch when

the power is connected. Disconnect both power
sources before manually operating the switch.

1. 100-200 amp switches: These switches have an
attached handle as shown in Figure 2-4.
400 amp switches: Slide the detachable handle or
a wrench over the shaft. See Figure 2-5.

2. Move the handle up to place the transfer switch in
the Normal Source position or down to place the
contactor in the Emergency Source position. See
Figure 2-4 or Figure 2-5.

3. 400 amp switches: Remove the detachable handle
or wrench.

SCE

NC

NO

C

7

8

CE

EL2EL1

1

1. Handle (not detachable)

Figure 2-4 Manual Operation, 100 and 200 Amp

Single-Phase Switches

1

GM80139

1. Shaft (attach handle or wrench here)

Figure 2-5 Manual Operation, 400 Amp Single-

Phase and 208--240 Volt Switches

2.4.2 Manual Operation Procedure 2

Note: Never use the maintenance handle to transfer the

load with the power connected. Disconnect both
power sources before manually operating the
switch.

1. If the transfer switch is equipped with a
maintenance handle, remove the handle from its
storage location inside the enclosure. See
Figure 2-7.

TP-6807 12/11 15Section 2 Installation

2. Insert the maintenance handle or a tool (such as a
screwdriver) into the hole in the shaft on the left
side of the operator as shown in Figure 2-6 or
Figure 2-7.

3. Move the maintenance handle (or tool) up or down
as shown to manually operate the transfer switch. It
should operate smoothly without any binding. If it
does not, check for shipping damage or
construction debris.

2.5 Electrical Wiring

Refer to the connection diagrams on the transfer switch
enclosure door and the wiring diagrams in Section 6
during installation.

All wiring must comply with applicable national, state,
and local electrical codes. Use separate conduit for AC
power wiring and low-voltage DC, control, and
communication system wiring.

4. Return the transfer switch to the Normal position.

5. Remove the maintenance handle and return it to the
storage location.

1

GM78867

1. Insert handle or tool here for manual operation

Figure 2-6 Manual Operation, 100--200 Amp

3-Phase Switches

DANGER

Hazardous voltage.
Will cause severe injury or death.

Disconnect all power sources before
opening the enclosure.

Making line or auxiliary connections. Hazardous voltage
can cause severe injury or death. To prevent electrical

shock deenergize the normal power source before making any
line or auxiliary connections.

Grounding electrical equipment. Hazardous voltage can
cause severe injury or death. Electrocution is possible

whenever electricity is present. Ensure you comply with all
applicable codes and standards. Electrically ground the
generator set and related equipment and electrical circuits.
Turn off the main circuit breakers of all power sources before
servicing the equipment. Never contact electrical leads or
appliances when standing in water or on wet ground because
these conditions increase the risk of electrocution.

2.5.1 Load Center Circuit Breakers

1

2

1. Handle storage location

2. Insert handle here for manual operation

Figure 2-7 Manual Operation, 400 Amp 3-Phase

Switches

The 100 amp Model RXT transfer switch is available
with a built-in load center with room for up to 16
single-pole circuit breakers. Up to 8 tandem breakers
can be used for a maximum of 24 circuits.

The load center uses Square D type QO or QOT tandem
breakers. In an essential load application, the breakers
can be moved from the main panel to the load center if
the main distribution panel uses the same type of
breakers. Otherwise, obtain and install new Square D
type QO circuit breakers. The rating of the load center
circuit breaker must match the rating of the existing
breaker in the main panel for each circuit. If circuit
breakers are removed from the load panel, install cover
plates over the vacant positions. Cover plates can be
obtained from a local Square D supplier.

tp6225

Verifythat the total rating for all breakers used in the load
center does not exceed the rating of the transfer switch.

TP-6807 12/1116 Section 2 Installation

2.5.2 AC Power Connections

Determine the cable size. Refer to Figure 2-8 or the
ADV drawings in Section 6 to determine the cable size
required for the transfer switch. Make sure the lugs
provided are suitable for use with the cables being
installed.

Conduit. Use separate conduit for AC power wiring
and low-voltage DC, control, and communication
system wiring. Watertight conduit hubs may be required
for outdoor use.

Select the proper cable clamp or use other approved
methods for securing the cable or conduit to the
enclosure.

Source and load connections. Clean cables with a
wire brush to remove surface oxides before connecting
them to the terminals. Apply joint compound to the
connections of any aluminum conductors.

Refer to the connection diagrams on the transfer switch
enclosure door and the wiring diagrams in Section 6.
The connection points on the transfer switch contactor
are labelled Normal, Emergency, and Load. Connect
the utility power to Normal. Connect the generator set to
Emergency.

Single phase. For single-phase models, connect to A
and C.

Three phase. For three-phase models, be sure to
follow the phase markings (A, B, C, and N).

Note: Connect the source and load phases as indicated

by the markings and drawings to prevent short
circuits and to prevent phase-sensitive devices
from malfunctioning or operating in reverse.

Service entrance models. Connect the utility source to
the lugs on the normal source disconnect circuit
breakers as shown in the service entrance switch wiring
diagram in Section 6.

Verify that all connections are consistent with drawings
before tightening the lugs. Tighten all cable lug
connections to the torque values shown on the label on
the switch. Carefully wipe off any excess joint
compound after tightening the terminal lugs.

On models with built-in load centers, the load lugs are
factory-wired to the load center. Connect the load leads
to the circuits in the load center and tighten the
connections. Check the labels on the breakers for the
tightening torques.

TP-6807 12/11 17Section 2 Installation

2.5.3 Neutral Connection

2.5.5 Engine Start Function

Connect the neutral from the main panel to the neutral
lug in the ATS enclosure.

Ground the system according to NEC and local codes.

2.5.4 Neutral Bonding Jumper, Service
Entrance Models

The transfer switch is shipped with the
neutral-to-ground jumper installed. For non-service
entrance applications, disconnect the neutral-to-ground
bonding jumper. See the transfer switch dimension
drawing.

Cable Sizes

AL/CU UL-Listed Solderless Screw-Type Terminals for External Power Connections

Switch

Size,

Amps

100

200

400

Figure 2-8 Cable Sizes

Switch Phases Normal and Emergency Load Neutral Ground

Standard 1 (1) #14 -- 1/0 AWG (1)#14–1/0AWG (3)#12–1/0AWG (9)#4–14AWG

With load

center

Service

Entrance

3-Phase 3 (1)#8–3/0AWG (1)#8–3/0AWG (3)#6AWG–3/0AWG (3)#6–3/0AWG

Standard 1 (1) #6 AWG – 250 MCM (1) #6 AWG – 250 MCM (3) #6 AWG – 250 MCM (9)#4–14AWG

Service

Entrance

3-Phase 3 (1) #6 AWG – 250 MCM (1) #6 AWG – 250 MCM

Standard 1 (2) #6 – 250 MCM (2) #6 – 250 MCM

Service

Entrance

3-pole

208-240 V

3 or 4 pole

480 V

1 (1)#14–1/0AWG

Normal: (1) #12 – 2/0

1

1

1

3 (2) #6 – 250 MCM (2) #6 – 250 MCM

3

AWG

Emerg: (1) #6 – 250

MCM

Normal: (1) #4 – 300

MCM

Emerg: (1) #6 -- 250

MCM

Normal: (2) 3/0 – 250

MCM

Emerg: (2) #6 -- 250

MCM

(1) #4 – 600 MCM
(2) #6 – 250 MCM

(1) #6 AWG – 250 MCM (3) #6 AWG – 250 MCM (3)#14–1/0AWG

The engine start function is controlled by the RDC2/DC2
controller on the generator set. There are no engine
start terminals on the Model RXT ATS.

Range of Wire Sizes, Cu/Al

per customer-supplied

circuit breaker

(1) #6 – 250 MCM (3) #6 – 250 MCM (3)#14–1/0AWG

(2) #6 – 250 MCM

(1) #4 – 600 MCM
(2) #6 – 250 MCM

(1)#2–2/0AWG (9)#4–14AWG

(3) #4 AWG – 600 MCM

(6) 1/0 – 250 MCM

(1) #4 – 600 MCM

(2) 1/0 – 250 MCM

(3) #4 – 600 MCM

(6) 1/0 – 250 MCM

(1) #4 – 600 MCM

(2) 1/0 – 250 MCM

(1) #4 – 600 MCM

(2) 1/0 – 250 MCM

(3)#6–3/0AWG

(3)#14–1/0AWG

TP-6807 12/1118 Section 2 Installation