Generac Power Systems RXGW20SHA3 User manual

Owner’s Manual
For
Automatic Transfer Switch
200 Amp, Single Phase, 240 VAC, Service Rated, 20–40 Circuit Load Center With Pass-Through Lugs
Model Number
RXGW20SHA3
SERIAL NUMBER: _________________________
DATE PURCHASED:________________________
WWW.GENERAC.COM
888-436-3722
Para español , visita: http://www.generac.com/service-support/product-support-lookup
Pour le français, visiter : http://www.generac.com/service-support/product-support-lookup
SAVE THIS MANUAL FOR FUTURE REFERENCE
003722

ii Automatic Transfer Switch Owner’s Manual
(000393a)
WARNING
CANCER AND REPRODUCTIVE HARM
www.P65Warnings.ca.gov.

Automatic Transfer Switch Owner’s Manual iii
Section 1: Safety Rules & General
Information
Introduction ..........................................................1
Read This Manual Thoroughly ....................................1
Safety Rules .........................................................1
General Hazards ..................................................1
Electrical Hazards ................................................2
Section 2: Installation
Introduction to Installation .................................5
Mounting the Enclosure ......................................5
Opening the Enclosure .......................................5
Installing Breakers ...............................................6
Installing Branch Circuit Conductors ................6
Connecting Power Source and Generator 
Power Supply .......................................................6
Connecting Start Circuit Wires ...........................7
Connecting SACM ...............................................8
Control of Air Conditioner Load ...................................8
Auxiliary Contact .................................................9
Fault Current Identification Label ......................9
Section 3: Operation
Functional Tests and Adjustments ..................11
Manual Operation ..............................................11
Close to Utility Source Side .......................................11
Close to Generator Source Side ...............................12
Return to Utility Source Side .....................................12
Voltage Checks ..................................................12
Utility Voltage Checks ...............................................12
Generator Voltage Checks ........................................12
Generator Tests Under Load ............................12
Checking Automatic Operation ........................13
Installation Summary ........................................13
Shutting Generator Down While 
Under Load .........................................................13
Shutting Generator Down To Perform 
Maintenance .......................................................14
Testing the SACM ..............................................14
Testing The SMM ...............................................14
Fuse Removal and Installation .........................14
Section 4: Drawings and Diagrams
Installation Drawing .......................................... 15
No. 10000047450 ......................................................15
Interconnection Drawing .................................. 16
No. 10000047283—Page 1 of 4 
(Liquid-Cooled Engine Generator) ............................16
No. 10000047283—Page 2 of 4 
(Liquid-Cooled Engine Generator) ............................17
No. 10000047283—Page 3 of 4 
(Air-Cooled Engine Generator) ..................................18
No. 10000047283—Page 4 of 4 
(Air-Cooled Engine Generator) ..................................19
Table of Contents

iv Automatic Transfer Switch Owner’s Manual
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Safety Rules & General Information
Automatic Transfer Switch Owner’s Manual 1
Section 1: Safety Rules & General Information
Introduction
Thank you for purchasing a Generac Power Systems Inc.
product. This unit has been designed to provide high
performance, efficient operation, and years of use when
maintained correctly.
The information in this manual is accurate based on
products produced at the time of publication. The manu-
facturer reserves the right to make technical updates,
corrections, and product revisions at any time without
notice.
Read This Manual Thoroughly
If any section of this manual is not understood, contact
the nearest Independent Authorized Service Dealer
(IASD) or Generac Customer Service at 1-888-436-3722
(1-888-GENERAC), or visit www.generac.com for start-
ing, operating, and servicing procedures. The owner is
responsible for correct maintenance and safe use of the
unit.
This manual must be used in conjunction with all other
supporting product documentation supplied with the
product.
SAVE THESE INSTRUCTIONS for future reference. This
manual contains important instructions that must be fol-
lowed during placement, operation, and maintenance of
the unit and its components. Always supply this manual
to any individual that will use this unit, and instruct them
on how to correctly start, operate, and stop the unit in
case of emergency.
Safety Rules
The manufacturer cannot anticipate every possible cir-
cumstance that might involve a hazard. The alerts in this
manual, and on tags and decals affixed to the unit, are
not all inclusive. If using a procedure, work method, or
operating technique that the manufacturer does not spe-
cifically recommend, verify that it is safe for others and
does not render the equipment unsafe.
Throughout this publication, and on tags and decals
affixed to the unit, DANGER, WARNING, CAUTION, and
NOTE blocks are used to alert personnel to special
instructions about a particular operation that may be
hazardous if performed incorrectly or carelessly. Observe
them carefully. Alert definitions are as follows:
NOTE: Notes contain additional information important to
a procedure and will be found within the regular text of
this manual.
These safety alerts cannot eliminate the hazards that
they indicate. Common sense and strict compliance with
the special instructions while performing the action or
service are essential to preventing accidents.
General Hazards
(000100a)
WARNING
Consult Manual. Read and understand manual
completely before using product. Failure to
completely understand manual and product
could result in death or serious injury.
(000001)
DANGER
Indicates a hazardous situation which, if not avoided,
will result in death or serious injury.
(000002)
WARNING
Indicates a hazardous situation which, if not avoided,
could result in death or serious injury.
(000003)
CAUTION
Indicates a hazardous situation which, if not avoided,
could result in minor or moderate injury.
(000237)
DANGER
Electrical backfeed. Use only approved switchgear to
isolate generator from the normal power source.
Failure to do so will result in death, serious injury,
and equipment damage.
(000188)
DANGER
Electrocution. Do not wear jewelry while
working on this equipment. Doing so will
result in death or serious injury.
(000213)
DANGER
Electrocution. Only authorized personnel should
access transfer switch interior. Transfer switch
doors should be kept closed and locked. Failure to
do so will result in death or serious injury.

Safety Rules & General Information
2Automatic Transfer Switch Owner’s Manual
IMPORTANT NOTE: See individual unit specifica-
tions for required maintenance and run times per-
taining to use.
•Competent, qualified personnel should install,
operate, and service this equipment. Strictly com-
ply to local, state, and national electrical and build-
ing codes. When using this equipment, comply with
regulations established by the National Electrical
Code (NEC), CSA Standard; the Occupational
Safety and Health Administration (OSHA), or the
local agency for workplace health and safety.
•If working on this equipment while standing on
metal or concrete, place insulative mats over a dry
wood platform. Work on this equipment only while
standing on such insulative mats.
•Never work on this equipment while physically or
mentally fatigued.
•Any voltage measurements should be performed
with a meter that meets UL3111 safety standards,
and meets or exceeds overvoltage class CAT III.
Electrical Hazards
Automatic start-up. Disconnect utility power and
render unit inoperable before working on unit.
Failure to do so will result in death or serious injury.
(000191)
DANGER
(000145)
DANGER
Electrocution. In the event of electrical accident,
immediately shut power OFF. Use non-conductive
implements to free victim from live conductor. Apply
first aid and get medical help. Failure to do so will
result in death or serious injury.
(000209b)
WARNING
Loss of life. This product is not intended to
be used in a critical life support application.
Failure to adhere to this warning could result
in death or serious injury.
WARNING
Equipment damage. This unit is not intended for use as a
prime power source. It is intended for use as an intermediate
power supply in the event of temporary power outage only.
Doing so could result in death, serious injury, and
equipment damage. (000247a)
(000129)
DANGER
Electrocution. High voltage is present at
transfer switch and terminals. Contact with
live terminals will result in death or serious
injury.
(000104)
DANGER
Electrocution. Water contact with a power
source, if not avoided, will result in death
or serious injury.
(000145)
DANGER
Electrocution. In the event of electrical accident,
immediately shut power OFF. Use non-conductive
implements to free victim from live conductor. Apply
first aid and get medical help. Failure to do so will
result in death or serious injury.
(000237)
DANGER
Electrical backfeed. Use only approved switchgear to
isolate generator from the normal power source.
Failure to do so will result in death, serious injury,
and equipment damage.
(000195)
DANGER
Electrocution, equipment and property damage.
Handle transfer switches carefully when installing.
Never install a damaged transfer switch. Doing so
could result in death or serious injury, equipment
and property damage.
(000123)
DANGER
Electrocution. Turn utility supply OFF before
working on utility connections of the transfer
switch. Failure to do so will result in death or
serious injury.
(000157)
DANGER
Electrocution. Do not disable or modify the
connection box door safety switch. Doing so
will result in death or serious injury.
Automatic start-up. Disconnect utility power and
render unit inoperable before working on unit.
Failure to do so will result in death or serious injury.
(000191)
DANGER

Safety Rules & General Information
Automatic Transfer Switch Owner’s Manual 3
(000119)
Equipment malfunction. Installing a dirty or damaged
transfer switch will cause equipment malfunction and
will result in death or serious injury.
DANGER
(000155a)
WARNING
Electric shock. Only a trained and licensed electrician
should perform wiring and connections to unit. Failure
to follow proper installation requirements could result in
death, serious injury, and equipment or property damage.
(000120)
CAUTION
Equipment damage. Verify all conductors are
tightened to the factory specified torque value.
Failure to do so could result in damage to the
switch base.
(000121)
CAUTION
Equipment damage. Perform functional tests in the
exact order they are presented in the manual.
Failure to do so could result in equipment damage.
(000134a)
CAUTION
Equipment damage. Exceeding rated voltage and
current will damage the auxiliary contacts. Verify
that voltage and current are within specification
before energizing this equipment.

Safety Rules & General Information
4Automatic Transfer Switch Owner’s Manual
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Installation
Automatic Transfer Switch Owner’s Manual 5
Section 2: Installation
Introduction to Installation
This equipment has been wired and tested at the factory.
Installing the transfer switch includes the following proce-
dures:
•Mounting the enclosure.
•Connecting power source and load leads.
•Connecting generator start and sensing circuit.
•Connecting any auxiliary contact (if needed).
•Testing functions.
Mounting the Enclosure
Mounting dimensions for the transfer switch enclosure
are in this manual. Enclosures are typically wall-
mounted. See Drawings and Diagrams.
This transfer switch is mounted in a UL type 3R enclo-
sure. It can be mounted outside or inside and should be
based on the layout of installation, convenience, and
proximity to the utility supply and load center.
Install transfer switch as close as possible to electrical
loads that will be connected to it. Mount transfer switch
vertically to a rigid supporting structure. Level all mount-
ing points to prevent transfer switch distortion. Use wash-
ers behind mounting holes to level the unit if necessary.
Opening the Enclosure
See Figure 2-1. First, remove outer cover (A):
1. Remove two thumb screws (B).
2. Slide slot (C) over retention tab.
3. Lower cover until clear of top flange (D), and pull
away from enclosure.
Then, remove inner panel (E):
4. Loosen nut (F).
5. Grasp inner panel at two cutouts (G—left and
right). Tilt inner panel as shown, passing nut
through t-slot (H) in inner panel.
6. Lower inner panel until clear of two retention slots
(J—left and right sides), and pull away from enclo-
sure.
Figure 2-1. Open Enclosure
(000119)
Equipment malfunction. Installing a dirty or damaged
transfer switch will cause equipment malfunction and
will result in death or serious injury.
DANGER
004086a
A
B
C
D
E
F
H
G
J

Installation
6Automatic Transfer Switch Owner’s Manual
Installing Breakers
See Figure 2-2. Insert tab on each breaker (A) into the
hook on the bus (B). Push breaker into bus until it snaps
into place.
Figure 2-2. Install Breakers
NOTE: The following 1 in circuit breaker manufacturers
are permitted to be installed: Siemens, Murray, Eaton
BR, and Square D Homeline.
Installing Branch Circuit Conductors
1. Install correctly sized branch circuit conductors into
transfer switch. Knockouts can be made in the field
as needed.
2. Connect ungrounded branch circuit conductors
(hot conductors) to a correctly sized circuit breaker
approved for use with the transfer switch.
3. Terminate neutral conductor and equipment
grounding conductor of the branch circuit at neu-
tral/equipment ground terminal bars.
4. Size all conductors, raceways, conduits, and junc-
tion boxes, if required, to the applicable NEC code
articles and follow NEC installation requirements
for wiring method(s) selected.
NOTE: Multi-wire branch circuits must be installed in
accordance with NEC Article 210.4.
Connecting Power Source and
Generator Power Supply
Installation and interconnection diagrams are provided in
this manual.
NOTE: All installations must comply with national, state,
and local codes. It is the responsibility of the installer to
perform an installation that will pass final electrical
inspection.
1. Connect utility supply at utility service disconnect
circuit breaker terminals N1 and N2. Utility supply
lugs are equipped with the 2017/2020 NEC
required finger safe barriers. These barriers must
remain in place after installation.
2. Connect utility neutral conductor to grounded ter-
minal bar. Neutral/grounding conductor terminal
bars are bonded together and to the transfer switch
enclosure through the use of a green main bonding
jumper screw.
3. Connect loads to integrated load center with cus-
tomer-supplied circuit breakers.
4. See Figure 2-1 and Figure 2-3. Connect generator
to generator terminals (E1 and E2) on the transfer
mechanism.
000362
B
A
Electrocution. Turn utility and emergency
power supplies to OFF before connecting
power source and load lines. Failure to do so
will result in death or serious injury. (000116)
DANGER
(000120)
CAUTION
Equipment damage. Verify all conductors are
tightened to the factory specified torque value.
Failure to do so could result in damage to the
switch base.

Installation
Automatic Transfer Switch Owner’s Manual 7
Figure 2-3. Wiring Connections
5. Connect generator neutral wire to top neutral lug or
side lugs on the panel board.
6. Connect neutral conductors to the lugs and termi-
nals along the neutral/ground bars in panel board
section of transfer switch.
7. Connect a maximum 200A subpanel feeder to
lower T1 and T2 connections. Connect feeder neu-
tral and equipment grounding conductors to the
neutral/grounding terminal bar in the transfer
switch.
8. Connect grounding electrode conductors to neu-
tral/ground terminal bars in panel board portion of
transfer switch.
NOTE: A neutral to equipment ground main bonding
screw (A) is provided for use where transfer switch is
installed as service equipment.
Conductor sizes must be adequate to handle maximum
current they will be subjected to, based on the 75 °C col-
umn of tables, charts, etc. used to size conductors.
Installation must fully comply with all applicable codes,
standards, and regulations.
All power cables can enter enclosure through provided
knockouts. Additional knockouts into transfer switch can
be made in the field as needed. Conduit entry shall main-
tain correct wire bending spaces required by Tables
312.6 (A) and (B) in the NEC. Conduits should be
arranged to provide separation between utility and gener-
ator supply conductors inside the enclosure.
NOTE: If aluminum conductors are used, apply corrosion
inhibitor to conductors. After tightening terminal lugs,
carefully wipe away any excess corrosion inhibitor.
Tighten terminal lugs to required torque values as noted
on decal located on the inside of the door. After tighten-
ing terminal lugs, carefully wipe away any excess corro-
sion inhibitor.
Connecting Start Circuit Wires
Control system interconnections consist of N1, N2, and
T1, and leads 23, 194, and 9 (ground). The connections
are color coded on the load shed to match connections in
the Generac genset. Generac Type TC-ER-JP tray cable
includes power cables with all necessary color-coded
control wiring. It is suitable for direct burial, overhead,
and indoor wiring.
NOTE: See Article 336 in the 2017 and 2020 editions of
the NEC for more information on the installation require-
ments for Type TC-ER-JP cable.
The generator control wiring is a Class 1 signaling circuit.
See instruction manual of specific engine generator for
wiring connection details. Recommended wire gauge
sizes for this wiring depends on wire length, as recom-
mended in the following chart:
Exception: Conductors of AC and DC circuits, rated
1000 volts nominal or less, shall be permitted to occupy
the same equipment, cable, or conduit. All conductors
shall have an insulation rating equal to at least the maxi-
mum circuit voltage applied to any conductor within the
equipment, cable, or conduit. See NEC 300.3(C)(1).
N2
004982a
N1
E1
E2
A
T1
T2
Maximum Wire Length Recommended Wire Size
1–115 ft (1–35 m) No. 18 AWG
116–185 ft (36–56 m) No. 16 AWG
186–295 ft (57–89 m) No. 14 AWG
296–460 ft (90–140 m) No. 12 AWG

Installation
8Automatic Transfer Switch Owner’s Manual
Connecting SACM
See Figure 2-4. The SACM can control an air conditioner
(24 VAC) directly.
Control of Air Conditioner Load
1. Route thermostat cable (from furnace/thermostat to
outdoor air conditioner unit) to transfer switch.
2. Connect wire to the terminal strip terminals (A/C 1)
on SACM as shown in Figure 2-4. These are nor-
mally closed contacts which open upon load shed
conditions. Route thermostat wire away from high
voltage wires.
3. If required, connect additional air conditioners to
the terminal strip terminals (A/C 2-4).
Contact Ratings
A/C 1-4 24 VAC, 1.0 amp max
A
B
G
H
C
D
E
F
T1N1N2
0 GROUND
194 +12V
N1
N2
T1
Replace with Littlefuse 021606.3MXHP
Generac 10000005117 250 vac, 6.3A
23 T RANSFER
1
1
1
1
2
2
2
2
®
J
T1
N2
0
194
23A
N1
004435
A—Thermostat 1
B—Air conditioner 1
C—Thermostat 2
D—Air conditioner 2
E—Thermostat 3
F—Air conditioner 3
G—Thermostat 4
H—Air conditioner 4
T1 (fused)—Battery Charge
(blue background, white letters)
N1 (fused)—Utility Sense
(yellow background, black letters)
N2 (fused)—Utility Sense
(yellow background with black
stripe, black letters)
0—Ground
(black background, white
letters)
194— +12 VDC
(red background, white letters)
23—Transfer Control
(white background, black
letters)
J—240 VAC, 6.3A Fuses
NOTE: These instructions are for a typical air conditioner
installation. Control of certain heat pumps and 2-stage air
conditioners may require special connections or the use
of SMMs to control the loads.
Figure 2-4. Typical SACM Connections

Installation
Automatic Transfer Switch Owner’s Manual 9
Auxiliary Contact
See Figure 2-5. If desired, there is one normally-closed
auxiliary contact (A) on the transfer switch to operate
customer accessories, remote advisory lights, or remote
annunciator devices. A suitable power source must be
connected to common terminal. If needed, an extra auxil-
iary contact can be added.
The auxiliary contact is normally closed when transfer
switch is in utility mode. Contacts will open when transfer
switch is in standby mode.
NOTE: Auxiliary contact is rated 10 amps at 125 or 250
volts AC, and 0.6 amps at 125 volts DC.
Figure 2-5. Auxiliary Contact
Fault Current Identification Label
See Figure 2-6. A Fault Current Identification Label is
provided in the bag containing the unit owner’s manual
and transfer switch manual operating handle. The 2017
NEC requires the short-circuit current rating of the trans-
fer equipment, based on type of overcurrent protective
device protecting transfer equipment, be field marked on
the exterior of the transfer equipment. For NEC compli-
ance, verify required short-circuit current rating of trans-
fer switch before installation. The completed label
provides the local Authority Having Jurisdiction (AHJ)
with information they may require during inspection.
Apply label to the exterior of the transfer switch enclo-
sure. Use a pen to fill in required information, and then
cover label with the clear protective decal.
Figure 2-6. Fault Current Identification Label
NOTE: The 2020 NEC code change omits this field
labeling requirement for one- and two-family dwelling
units.
(000134a)
CAUTION
Equipment damage. Exceeding rated voltage and
current will damage the auxiliary contacts. Verify
that voltage and current are within specification
before energizing this equipment.
003626
A
004496

Installation
10 Automatic Transfer Switch Owner’s Manual
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Operation
Automatic Transfer Switch Owner’s Manual 11
Section 3: Operation
Functional Tests and Adjustments
Following transfer switch installation and interconnection,
inspect entire installation carefully. A competent, qualified
electrician should inspect it. The installation should
strictly comply with all applicable codes, standards, and
regulations. When absolutely certain installation is cor-
rect, complete a functional test of the system.
IMPORTANT NOTE: Before proceeding with func-
tional tests, read and verify all instructions and infor-
mation in this section is understood. Also read
information and instructions of labels and decals
affixed to transfer switch. Note any options or acces-
sories that might be installed and review their opera-
tion.
Manual Operation
See Figure 3-1. A manual handle (B) is shipped with the
transfer switch manual. Manual operation must be veri-
fied BEFORE transfer switch is operated electrically. Pro-
ceed as follows to verify manual operation:
1. Verify generator is in OFF mode.
2. Turn off both utility (service disconnect circuit
breaker) and emergency (generator main line cir-
cuit breaker) power supplies to transfer switch.
3. Note position of transfer mechanism main contacts
(A) by observing the movable contact carrier arm.
This can be viewed through the long narrow slot in
the inside cover. The top of the movable contact
carrier arm is yellow to be easily identified.
•Manual operation handle in UP position—
LOAD terminals (T1, T2) are connected to util-
ity terminals (N1, N2).
•Manual operation handle in DOWN position–
LOAD terminals (T1, T2) are connected to
EMERGENCY terminals (E1, E2).
Close to Utility Source Side
Before proceeding, verify position of transfer switch by
observing position of manual operation handle in Figure
3-1. If manual operation handle is UP, contacts are
closed in utility (normal) position. No further action is
required. If manual operation handle is DOWN, proceed
with Step 1.
1. With manual operation handle inserted into mov-
able contact carrier arm, move handle UP. Hold on
to manual operation handle as it will move quickly
after the center of travel.
2. Remove manual operating handle from movable
contact carrier arm. Return manual operation han-
dle to storage bracket.
Figure 3-1. Manual Operation
(000121)
CAUTION
Equipment damage. Perform functional tests in the
exact order they are presented in the manual.
Failure to do so could result in equipment damage.
(000132)
DANGER
Electrocution. Do not manually transfer under load.
Disconnect transfer switch from all power sources
prior to manual transfer. Failure to do so will result in
death or serious injury, and equipment damage.
(000122)
CAUTION
Equipment damage. Do not use excessive force while
manually operating the transfer switch. Doing so could
result in equipment damage.
B
009339
A

Operation
12 Automatic Transfer Switch Owner’s Manual
Close to Generator Source Side
Before proceeding, verify position of transfer switch by
observing the position of the manual operation handle in
Figure 3-1. If manual operation handle is DOWN, con-
tacts are closed in generator (standby) position. No fur-
ther action is required. If manual operation handle is UP,
proceed with Step 1.
1. With manual operation handle inserted into mov-
able contact carrier arm, move manual operation
handle DOWN. Hold on to manual operation han-
dle as it will move quickly after the center of travel.
2. Remove manual operating handle from movable
contact carrier arm. Return manual operation han-
dle to storage bracket.
Return to Utility Source Side
Proceed as follows to return to utility source side:
1. Manually actuate transfer switch to return manual
operating handle to the UP position.
2. Remove manual operating handle from movable
contact carrier arm. Return manual operation han-
dle to storage bracket.
Voltage Checks
NOTE: Use the Digital Multimeter (DMM) LowZ low input
impedance setting to collect accurate voltage measure-
ments. LowZ eliminates the possibility of inaccurate
ghost voltage readings, also known as phantom voltage
or stray voltage readings. See DMM manufacturer’s liter-
ature for additional information.
Utility Voltage Checks
Proceed as follows to check utility voltage:
1. Turn on utility power supply to transfer switch using
utility service disconnect circuit breaker.
2. With an accurate AC voltmeter, check for correct
voltage. Measure across ATS terminal lugs N1 and
N2; N1 to NEUTRAL and N2 to NEUTRAL.
Generator Voltage Checks
Proceed as follows to check generator voltage:
1. Select MANUAL mode on generator panel. Gener-
ator will crank and start.
2. Allow generator to stabilize and warm up at no-load
for at least five minutes.
3. Set generator's main circuit breaker (CB1) to ON
(CLOSED).
4. Verify no-load, voltage, and frequency with an
accurate AC voltmeter and frequency meter. Mea-
sure across ATS terminal lugs E1 to E2; E1 to
NEUTRAL and E2 to NEUTRAL.
Frequency 60–62 Hz
Terminals E1 to E2 240–246 VAC
Terminals E1 to NEUTRAL 120–123 VAC
Terminals E2 to NEUTRAL 120–123 VAC
5. Turn off generator supply to transfer switch when
generator supply voltage is correct and compatible
with transfer switch ratings.
6. Set generator main circuit breaker (CB1) to OFF
(OPEN).
7. Press OFF on generator panel to shut down gener-
ator.
IMPORTANT NOTE: DO NOT proceed until generator
AC output voltage and frequency are correct and
within stated limits. If no-load voltage is correct but
no-load frequency is incorrect, engine governed
speed may require adjustment. If no-load frequency
is correct but voltage is not, voltage regulator may
require adjustment.
Generator Tests Under Load
Proceed as follows to perform generator tests under
load:
1. Set generator main line circuit breaker (MLCB) to
OFF (OPEN).
2. Set utility service disconnect circuit breaker of the
transfer switch to OFF (OPEN), and turn OFF
(OPEN) all load circuit breakers.
3. Manually actuate transfer switch main contacts to
emergency (STANDBY) position. See Manual
Operation.
4. Select MANUAL mode to start the generator. Allow
engine to stabilize for a few minutes, and close lid.
(000129)
DANGER
Electrocution. High voltage is present at
transfer switch and terminals. Contact with
live terminals will result in death or serious
injury.
(000123)
DANGER
Electrocution. Turn utility supply OFF before
working on utility connections of the transfer
switch. Failure to do so will result in death or
serious injury.
(000129)
DANGER
Electrocution. High voltage is present at
transfer switch and terminals. Contact with
live terminals will result in death or serious
injury.

Operation
Automatic Transfer Switch Owner’s Manual 13
5. Set generator MLCB to ON (CLOSED). Generator
now powers all LOAD circuits. Verify generator
operation under load as follows:
•Turn on electrical loads to the full rated watt-
age/amperage capacity of generator. DO NOT
OVERLOAD.
•With maximum rated load applied, check volt-
age and frequency across transfer switch ter-
minals E1 and E2. Voltage should be greater
than 230 VAC (240 VAC system); frequency
should be greater than 59 Hz.
•Verify fuel pressure remains within acceptable
parameters (see generator installation man-
ual).
•Allow generator to run under rated load for at
least 30 minutes. With unit running, inspect for
unusual noises, vibration, or overheating that
might indicate a problem.
6. Set generator MLCB to OFF (OPEN) when test
under load is complete.
7. Allow generator to run at no-load for several min-
utes. Then, shut down generator by pressing OFF.
8. Set main switch contacts to utility.
NOTE: See Manual Operation. Handle and operating
lever of transfer switch should be in down position.
9. Set utility service disconnect circuit breaker of
transfer switch to ON (CLOSED).
System is now set for fully automatic operation.
Checking Automatic Operation
Proceed as follows to check system for correct automatic
operation:
1. Verify generator is in OFF mode.
2. Set utility service disconnect circuit breaker of the
transfer switch to OFF (OPEN).
3. Verify switch is de-energized.
4. Install front cover of transfer switch.
5. Set transfer switch utility service disconnect circuit
breaker to ON (CLOSED).
6. Set generator MLCB to ON.
7. Select AUTO on generator control panel. System is
now ready for automatic operation.
8. Set transfer switch utility service disconnect circuit
breaker to OFF (OPEN).
With generator ready for automatic operation, engine
should crank and start when utility source power is turned
off after a five second delay (factory default setting). After
starting, transfer switch should connect load circuits to
standby side after a five second delay. Allow system to
operate through entire automatic sequence of operation.
With generator running and loads powered by generator
AC output, set transfer switch utility service disconnect
circuit breaker to ON (CLOSED). The following will occur:
•After approximately 15 seconds, transfer switch will
transfer loads to utility power source.
•Approximately one minute after transfer, generator
should shut down.
With generator in AUTOMATIC mode, system is now set
for fully automatic operation.
Installation Summary
1. Verify installation has been performed correctly as
outlined by the manufacturer and that it meets all
applicable laws and codes.
2. Test and verify correct operation of the system as
outlined in the appropriate installation and owner’s
manuals.
3. Educate end-user on correct operation, mainte-
nance, and service call procedures.
NOTE: The utility power circuit breaker in transfer switch
must be turned OFF to simulate a utility outage. Shutting
off main disconnect in a subpanel connected to transfer
switch will NOT simulate an outage.
Shutting Generator Down While
Under Load
IMPORTANT NOTE: To avoid equipment damage, fol-
low these steps, in order, when shutting the genera-
tor down during utility outages. Shutdowns may be
required during outages to perform routine mainte-
nance or to conserve fuel.
To turn generator OFF (while running in AUTO and
online):
1. Turn main utility disconnect off.
2. Turn generator MLCB (generator disconnect) to
OFF (OPEN).
3. Run generator for approximately one minute to
cool down.
4. Turn generator OFF.
To turn generator back ON:
1. Put generator into AUTO mode. Start generator
and warm-up for a few minutes.
2. Set MLCB (generator disconnect) to ON
(CLOSED).
The system now operates in AUTO mode. The main util-
ity disconnect can be turned ON (CLOSED). To shut unit
off, repeat this complete process.

Operation
14 Automatic Transfer Switch Owner’s Manual
Shutting Generator Down To Perform
Maintenance
Proceed as follows to shut down generator for mainte-
nance:
1. Press OFF button on controller.
2. Turn main utility disconnect OFF (OPEN).
3. Turn MLCB (generator disconnect) on generator to
OFF (OPEN) and follow maintenance proce-
dure(s).
To turn generator back ON:
1. Turn main utility disconnect ON (CLOSED).
2. Put generator into AUTO mode.
3. Set MLCB (generator disconnect) on generator to
ON (CLOSED).
The system is now in AUTO mode.
Testing the SACM
A TEST pushbutton is provided on top of the SACM to
test operation of load shed functions. The TEST button
will work when ATS is in utility or generator position. Pro-
ceed as follows to test the SACM:
1. Turn on utility supply to ATS.
2. Verify managed loads are powered and all LEDs
illuminate on SACM.
3. Press TEST button on the SACM.
4. Verify all of the connected loads to be “shed” are
disabled.
5. After five minutes, verify A/C 1 is energized and
Status LED A/C 1 is ON.
6. After another 15 seconds, verify A/C 2 is energized
and Status LED A/C 2 is ON.
7. After another 15 seconds, verify Load A/C 3 is
energized and Status LED Load A/C 3 is ON.
8. After another 15 seconds, verify A/C 4 is energized
and Status LED A/C 4 is ON.
Testing The SMM
See SMM owner’s/installation manual for testing proce-
dure.
Fuse Removal and Installation
See Figure 3-2. A fuse removal and installation tool (A)
is included in the control housing.
Figure 3-2. Fuse Removal and Installation Tool
If a fuse requires replacement, snap tool free with an
appropriate tool such as diagonal pliers, and use it to
replace fuse. The tool can be stored in the control hous-
ing retainer directly above the fuses, with the large thumb
tab facing out.
Use only Generac replacement fuses—part number
100000005117, rated 240 VAC, 6.3 Amps, 10,000 AIC.
Alternative fuses are Littelfuse® 021606.3MXHP or Opti-
fuse® FCD-6.3.
10000004183
Rev. A
M1704
A005450

Drawings and Diagrams
Automatic Transfer Switch Owner’s Manual 15
Section 4: Drawings and Diagrams
Installation Drawing
No. 10000047450

Drawings and Diagrams
16 Automatic Transfer Switch Owner’s Manual
Interconnection Drawing
No. 10000047283—Page 1 of 4 (Liquid-Cooled Engine Generator)