Introduction
The Kohler Model RXT Automatic Transfer Switch is designed for seamless integration with Kohler® generator sets equipped with RDC2 or DC2 generator set/transfer switch controls. The transfer switch operation is managed by the RDC2/DC2 controller, ensuring reliable automatic power transfer.
An illustration shows the Kohler RXT Automatic Transfer Switch with its covers removed, revealing the internal components and wiring.
Available Models Overview
- 100, 200, and 400 amp standard and service entrance models are available.
- 150 and 300 amp service entrance models are also available.
- A combined interface/load management board is available on single-phase standard and service entrance models (not available on 3-phase or load center models).
- 100 amp standard single-phase models are offered with or without a 16-space load center. Up to 8 tandem breakers can be used for a total of 24 circuits.
- A 100 amp standard single-phase model with a 12-space load center and a NEMA 1 enclosure is available as a standalone non-configurable specification (GM85273-SA_).
See page 7 for more detailed model information.
Standard Features
- Allows utility voltage display on the RDC2/DC2 generator set/transfer switch controller, exclusively available on Kohler® residential and light commercial generator sets.
- UL listed.
- Models with load centers are UL 67 listed (file #E251086).
- Models without load centers are UL 1008 listed (file #E58962).
- CSA certification (file #LR58301) is available for:
- Standard ATS without load center (single and three-phase).
- Service entrance ATS 100 and 200 amp models.
- Corrosion-resistant NEMA 3R aluminum enclosure.
- Padlockable.
- Approved for indoor or outdoor installation.
- ANSI 49 gray finish.
- NEMA 1 enclosure available on 100 amp load center models.
- Contactor electrically and mechanically interlocked.
- Double throw inherently interlocked design.
- Contactor manually operable for maintenance purposes.
- Silver alloy main contacts.
- Transfer switches are 100% equipment rated and can be applied at the rated current without derating (non-service entrance models).
- Service entrance models include a disconnect circuit breaker on the utility (normal) source side (80% rated).
- Five-year limited warranty.
Interface Boards
Standard Interface Board
The standard interface board connects to the Model RDC2 or DC2 generator set/transfer switch controller. It includes a load control contact that provides a 5-minute time delay for startup of selected loads after transfer to the emergency source, suitable for large motor loads.
Optional Combined Interface/Load Management Board
This optional board replaces the standard interface board and connects to the Model RDC2 or DC2 generator set/transfer switch controller. It is available on single-phase standard and service entrance models (not available on 3-phase or load center models).
Load Management
- Disconnects non-critical loads to prevent generator overload, in compliance with NEC.
- Monitors generator current and frequency to determine when to add or shed loads, preventing frequency drops that can damage electronics.
- Allows the use of a smaller generator set.
Operation
- Loads are automatically added or shed based on generator capacity.
- Uses dynamic logic to prevent shedding important loads unnecessarily when air conditioning, refrigerator, or water pump motors start (patent pending).
- Communicates with the generator for smart power management, reducing the time to shed loads to adapt to critical power requirements.
- Load shed power level and frequency setpoints can be adjusted using Kohler® Site Tech™ software (available to authorized distributors and dealers).
Priority Setting
- Loads are added and shed according to their priority (Load 1 is highest, Load 6 is lowest).
- Less critical loads can be turned off automatically when essential appliances are running.
- Load priorities are hard-wired at installation.
Viewing Load Shed Outputs with OnCue® Plus
- Use Kohler's OnCue® Plus Generator Management System (sold separately) to view load status (On or Off) for loads connected to the load shed relays.
- Remotely monitor when loads are shed or added.
- Load shed outputs can be labeled in OnCue® Plus.
Current Transformer
- The combined load management board option includes a 400 amp current transformer (CT) for load monitoring.
- A larger diameter CT is available for applications requiring larger cables.
- A 500 amp CT is available for use with a 60RCL generator.
Specifications
Standard Interface Board Specifications
| Description | Rating | Connection |
|---|---|---|
| Controller interface connections A and B | #20 AWG shielded twisted-pair Belden 9402 or 8762 or equivalent | |
| Controller interface connections PWR and COM | #12-20 AWG (see ATS Installation Manual) | |
| Load control contact rating | 10 A @ 250 VAC | |
| Load control connections | #12-18 AWG |
For combined interface/load management board specifications, see page 3.
Environmental Specifications
| Parameter | Value |
|---|---|
| Operating temperature | -20°C to 70°C (-4°F to 158°F) |
| Storage temperature | -40°C to 85°C (-40°F to 185°F) |
| Humidity | 5 to 95% noncondensing |
Codes and Standards
The ATS meets or exceeds the requirements of the following specifications:
- Underwriters Laboratories UL 67, Enclosed Panel Boards (load center models) file #E251086
- Underwriters Laboratories UL 1008, Standard for Automatic Transfer Switches for Use in Emergency Systems, file #E58962
- Underwriters Laboratories UL 508, Standard for Industrial Control Equipment
- CSA certification available, file #LR58301 (not available for 150, 300, or 400 amp service entrance or 100 amp load center models). Must be selected when the transfer switch is ordered.
- NFPA 70, National Electrical Code
- NFPA 110, Emergency and Standby Power Systems
- NEMA Standard IC10-1993, AC Automatic Transfer Switches
Cable Sizes (AL/CU UL-Listed Solderless Screw-Type Terminals for External Power Connections)
| Switch Size, Amps | Switch | Phases | Range of Wire Sizes, Cu/Al | |||
|---|---|---|---|---|---|---|
| Normal and Emergency | Load | Neutral | Ground | |||
| 100 | Standard | 1 | (1) #14 - 1/0 AWG | (1) #14 - 1/0 AWG | (5) #12 to 250 KCMIL (Cu) or (5) #10 to 250 KCMIL (AI) | (9) #6-#14 AWG (4) #14 - 1/0 AWG |
| 12-space load center (NEMA 1) | 1 | (1) #14 - 1/0 AWG | per customer-supplied circuit breaker | (13) #4 - 14 AWG or (1) #6 - 2/0 AWG | ||
| 16-space load center (NEMA 3R) | 1 | (1) #14 - 1/0 AWG | per customer-supplied circuit breaker | (27) #4 - 14 AWG or (3) #4 - 1/0 AWG or (1) #6 - 2/0 AWG | ||
| Service Entrance | 1 | Normal: (1) #12 – 2/0 AWG Emerg: (1) #14 – 1/0 AWG | (1) #14 - 1/0 AWG | (5) #12 to 250 KCMIL (Cu) or (5) #10 to 250 KCMIL (AI) | ||
| 150 | 3-Phase | 3 | (1) #14 - 1/0 AWG | (1) #14 - 1/0 AWG | (3) #4 AWG - 600 KCMIL (6) 1/0 AWG - 250 KCMIL | (4) #14 - 1/0 AWG (9) #14 - #6 AWG |
| Service Entrance | 1 | Normal: (1) #4 – 300 KCMIL Emerg: (1) #6 - 250 KCMIL | (1) #6 - 250 KCMIL | (5) #12 to 250 KCMIL (Cu) or (5) #10 to 250 KCMIL (AI) | ||
| 200 | Standard | 1 | (1) #6 AWG - 250 KCMIL | (1) #6 - 250 KCMIL | (5) #12 to 250 KCMIL (Cu) or (5) #10 to 250 KCMIL (AI) | (9) #14 – #4 AWG (4) #14 - 1/0 AWG |
| 3-Phase | 3 | (1) #14 - 1/0 AWG | (1) #14 - 1/0 AWG | (3) #4 AWG - 600 KCMIL (6) 1/0 AWG - 250 KCMIL | (4) #14 - 1/0 AWG (9) #14 - #6 AWG | |
| 300 | Service Entrance | 1 | Normal:: (1) #1 - 600 KCMIL or (2) #1250 KCMIL Emerg: (2) #6 - 250 KCMIL | (2) #6 - 250 KCMIL | (3) #4 AWG - 600 KCMIL (6) 1/0 AWG - 250 KCMIL | (6) #6 - 3/0 AWG |
| Standard | 1 | (2) #6 - 250 KCMIL | (2) #6-250 KCMIL | (3) #4 AWG - 600 KCMIL (6) 1/0 AWG – 250 KCMIL | (6) #6 - 3/0 AWG | |
| 400 | 3-pole 208-240 V | 3 | (1) #4-600 KCMIL (2) 1/0 – 250 KCMIL | (1) #4 - 600 KCMIL (2) 1/0 - 250 KCMIL | (3) #4 AWG - 600 KCMIL (6) 1/0 AWG – 250 KCMIL | (6) #6 - 3/0 AWG |
| 3 or 4 pole 480 V | 3 | (1) #4-600 KCMIL (2) 1/0 – 250 KCMIL | (1) #4 - 600 KCMIL (2) 1/0 - 250 KCMIL | (3) #4 AWG - 600 KCMIL (6) 1/0 AWG – 250 KCMIL | (6) #6 - 3/0 AWG | |
Note: Data is subject to change. Refer to the transfer switch dimension drawings and wiring diagrams for planning and installation.
Load Shed Specifications
| Connection | Rating | Connection |
|---|---|---|
| Pilot Relays* | 125VAC, 10 A total (general purpose) 120VAC, 125VA (pilot duty) | #12-20 AWG |
| HVAC Relays (qty. 2) | 125VAC, 10 A (general purpose) 120VAC, 125VA (pilot duty) | #12-20 AWG |
| RBUS Communication and Power Connections to the RDC2/DC2 controller | 0.5 A @ 12 VDC | Use Belden #9402 or equivalent 20 AWG shielded, twisted-pair communications cable † |
* Four (4) pilot relays are provided for customer-supplied normally closed load-switching contactors/relays. The combination of four load relay outputs cannot exceed 10 amps total current draw. Kohler® power relay modules are recommended.
† For long distances, use an equivalent shielded, twisted-pair cable for RBUS connections and individual 12-20 AWG wires (qty. 2) for power connections.
Current Transformer Specifications
| Ratio (Amps:VAC) | Outer Diameter mm (in.) | Inner Diameter mm (in.) | Service Part Number | Sales Kit Part Number | CT Availability |
|---|---|---|---|---|---|
| 400:3 | 63.5 (2.5) | 28.7 (1.13) | GM83929 | N/A | Included with combined board |
| 400:3 | 111.8 (4.4) | 57.2 (2.25) | GM17250 | GM17250-KP1-QS | Sold Separately |
| 500:3 | 171.5 (6.75) | 108.0 (4.25) | GM60264 | GM17250-KP2-QS | Sold Separately (use with 60RCL) |
Ratings
Service Entrance Transfer Switch Ratings
The service entrance transfer switch is factory-equipped with a normal source disconnect circuit breaker.
Suitable for the control of motors, electric discharge lamps, tungsten filament lamps and electric heating equipment where the sum of motor full-load ampere ratings and the ampere ratings of other loads do not exceed the ampere rating of the switch and the tungsten load does not exceed 30 percent of switch rating.
| Switch Rating, Amps * | WCR, RMS Symmetrical Amps at 240 VAC |
|---|---|
| 100, 150, 200 | 22,000 |
| 300, 400 | 35,000 |
* Continuous load current not to exceed 80% of switch rating.
Contactor Ratings with Coordinated Circuit Breakers
Single-phase transfer switches are UL listed at 240 VAC maximum. Three-phase transfer switches are rated at 480 VAC maximum. The following table lists contactor withstand current ratings (WCR) for 100-400 ampere non-service entrance rated switches with specific manufacturer's circuit breakers per UL and Canadian safety standards. Suitable for the control of motors, electric discharge lamps, tungsten filament lamps and electric heating equipment where the sum of motor full-load ampere ratings and the ampere ratings of other loads do not exceed the ampere rating of the switch and the tungsten load does not exceed 30 percent of switch rating.
The transfer switch is rated for use on a circuit capable of delivering not more than the RMS symmetrical amperes maximum as shown in the tables below, but no greater than the interrupting capacity of the selected breaker.
WCR Ratings with Specific Manufacturer's Molded-Case Circuit Breakers (Part 1)
| Switch Rating, Amps | Voltage, max. | Number of Poles/ Phases | WCR, RMS Symmetrical Amps | Manufacturer | Type or Class | Maximum Size, Amps |
|---|---|---|---|---|---|---|
| 100 | 240 | 2 pole/ 1 phase | 10,000 | Any Breaker * | Any Breaker (0.025 seconds max.) | -- |
| 150 | 240 | 2 pole/ 1 phase | 10,000 | Any Breaker * | Any Breaker (0.025 seconds max.) | -- |
| 200 | 240 | 2 pole/ 1 phase | 10,000 | Eaton | FCL JGS, JGH, JGC, JGU, JGX, JBD, JD, HJD, JDC, LCL, LCLA LDC, CLDC, KDB, KD, HKD, KDC, LD, CLD, HLD, CHLD | 100 250 400 |
| ITE/Siemens | CED6, HED4, HED6 CFD6, FD6A, FXD6, HFD6, HFXD6, HHFD6, HHFXD6 CJD6 | 125 250 400 | ||||
| 100 | 480 | 3 pole/ 3 phase | 30,000 | General Electric | SEL, SEP, THLC1, PE E, PE N, PE H, PE L THLC2 | 150 225 |
| 200 | 480 | 4 pole/ 3 phase | 30,000 | General Electric | SFH, SFL, SFP, PE E, PE N, PE H, PE L SGH, SGL, SGP, FGN, FGH, FGL, FGP, PG_E, PG_N, PG_H, PG_L, PG_P | 250 400 |
| Schneider | HG, HJ, HL, HR JJ, JL, JR LG, LJ, LL, LR | 150 250 400 |
* For higher WCR values, contact the factory for additional specific breaker ratings.
WCR Ratings with Specific Manufacturer's Molded-Case Circuit Breakers (Part 2)
| Switch Rating, Amps | Voltage, max. | Number of Poles/ Phases | WCR, RMS Symmetrical Amps | Manufacturer | Type or Class | Maximum Size, Amps |
|---|---|---|---|---|---|---|
| 300 | 240 | 2 pole/ 1 phase | 35,000 | ABB | T5, T6 | 600 |
| Eaton | CHKD, CKD, DK, HKD, KD, KDB, KDC, LA TRIPAC, LCL CHLD, CLD, CLDC, HLD, LD, LDB, LDC HMDL, MDL, NB TRI-PAC | 400 600 800 | ||||
| Siemens | CMD, HLMD, HLMXD, HMD, HMG, HMXD, LMD, LMG, LMXD, MD, MXD, NMG, SCMD, SHMD, SMD | 800 | ||||
| 240 | 2 pole/ 1 phase | 35,000 | Square D | LA, LC, LE, LH, LI, LX, LXI DG, DJ, DL, LC, LE, LI, LX, LXI | 400 600 | |
| Merlin Gerin | CJ400H, CJ400L, CJ400N CJ600H, CJ600N | 400 600 | ||||
| 300 | 240 | 3 pole/ 3 phase | 35,000 | Any Breaker | Any Breaker (0.017 seconds max.) | 600 |
| Eaton | LD HJD, JDC, JGC, JGH, JGU, JGX | 600 250 | ||||
| 400 | 480 | 3 pole/ 3 phase | 50,000 | Eaton | CHLD4, CLD, HLD4, CLDC, LDC, KDC, HKD, CHMDL4, CMDL4 CHLD6, HDL6, CHMDL6, CMDL6, CLDC, CLD6, LDC6, CLDC6 CHMDL8, HMDL8, MDL8, CMDL8 | 400 600 800 |
| ITE/Siemens | CFD6, HFD6, HFXD6, HHFD6, HHFXD6 CJD6 CLD6, HHLD6, HHLXD6, HLD6, HLXD6 | 250 400 600 | ||||
| General Electric | CMD6, MD6, HMD6, HMXD6, MXD6 SEL, SEP, PE_N, PE_H, PE_L SFL, SFP, PE_N, PE_H, PE_L SGL, SGP | 800 150 250 400 | ||||
| General Electric | FGL, FGP, SGL, SGP, PG_H, PG_L, PG_N, PG_P | 600 | ||||
| Schneider | HG, HL, HR JJ, JL, JR LJ, LL, LR | 150 250 600 | ||||
| Schneider | MJ | 800 |
Dimensions and Weights
Note: Always use the transfer switch dimension drawing for planning and installation. Weights and dimensions may vary for different configurations. See the Operation/Installation Manual or your local distributor for dimension drawings.
Transfer switch weights and dimensions shown in the table do not include packaging. To estimate the shipping weight, add 3 kg (5 lbs.) or 10% (whichever is larger) to the weight shown.
| Amps | Description | Dimensions, H x W x D, mm (in.) † | Shipping Weight kg (lb.) | Dimension Drawing |
|---|---|---|---|---|
| 100 | Single phase | 623 x 335 x 180 (24.5 x 13.2 x 7.1) | 7 (15) | ADV-8688 |
| With 12- or 16-space load center (NEMA 1) | 610 x 330 x 154 (24.0 x 13.0 x 6.0) | 12 (26) | ADV-8487 | |
| With 16-space load center | 614 x 335 x 180 (24.2 x 13.2 x 7.1) | 8 (18) | ADV-8690 | |
| Three phase | 682 x 462 x 228 (26.8 x 18.2 x 9.0) | 14 (30) | ADV-8689 | |
| 150 | Service entrance (ASE) | 734 x 416 x 175 (28.9 x 16.4 x 6.9) | 10 (22) | ADV-9046 |
| Service entrance (CSE) | 754 x 416 x 175 (29.7 x 16.4 x 6.9) | 14 (30) | ADV-8797 | |
| 200 | Service entrance (ASE) | 734 x 416 x 175 (28.9 x 16.4 x 6.9) | 12 (26) | ADV-9046 |
| Service entrance (CSE) | 754 x 416 x 175 (29.7 x 16.4 x 6.9) | 16 (36) | ADV-8798 | |
| 100 | Single phase | 623 x 335 x 180 (24.5 x 13.2 x 7.1) | 7 (15) | ADV-8688 |
| Three phase | 682 x 462 x 228 (26.8 x 18.2 x 9.0) | 14 (30) | ADV-8689 | |
| 300 | Service entrance | 1075 x 559 x 329 (42.3 x 22.0 x 12.9) | 46 (101) | ADV-8694 |
| 400 | Single phase | 1067 x 559 x 329 (42.0 x 22.0 x 12.9) | 55 (120) | ADV-8691 |
| 3-Pole/208-240 volts | 1067 x 559 x 329 (42.0 x 22.0 x 12.9) | 41 (90) | ADV-8692 | |
| 3-Pole/480 volts | 1222 x 610 x 343 (48.1 x 24.0 x 13.5) | 59 (130) | ADV-8693 | |
| 400 | 4-Pole | 1222 x 610 x 343 (48.1 x 24.0 x 13.5) | 59 (130) | ADV-8693 |
| 400 | Service entrance | 1075 x 559 x 329 (42.3 x 22.0 x 12.9) | 46 (101) | ADV-8694 |
† Depth does not include the padlock hasp on the front of the enclosure.
Transfer switch weights are approximate and do not include packaging.
Note: Enclosures are type NEMA 3R except as noted.
Accessories
- Auxiliary position-indicating contacts:
- One closed on normal position and one closed on emergency position.
- Form C contacts rated 15 A @ 250 VAC.
- Power relay modules:
- 50 amp DPST power relay mounted in a NEMA type 3R enclosure.
- Use up to four modules with the combined interface/load management board.
- UL/cUL listed.
- Dimensions: 172 x 233 x 92 mm (6.8 x 9.2 x 3.6 in.).
- For more information, see specification sheet G6-143.
- Status indicator kit for standard interface board:
- LEDs indicate normal and emergency source availability and contactor position.
- Mounts on the outside of the RXT enclosure.
- View transfer switch status without removing enclosure cover.
- An overhang on the enclosure protects the indicator panel and ribbon cable opening.
- Dimensions: 92 mm x 42 mm (3.62 in. x 1.65 in.).
- Connects to the standard interface board only.
- For more information on the status indicator kit, see specification sheet G11-123.
- Status indicator kit for combined interface/load management board:
- LEDs indicate normal and emergency source availability and contactor position.
- Dual color LEDs for each load indicate load status (powered or shed) and flash during a test.
- Load shed test button allows the operator to cycle the load shed relays in order of priority (when generator is in RUN mode).
- Mounts on the outside of the RXT enclosure.
- View transfer switch and load status without removing enclosure cover.
- An overhang on the enclosure protects the indicator panel and ribbon cable opening.
- Dimensions: 183 mm x 42 mm (7.20 in. x 1.65 in.).
- Connects to the combined interface/load management board only.
- For more information on the status indicator kit, see specification sheet G11-123.
- Auxiliary circuit breaker (service entrance models only):
- 15 amp single-pole type QO circuit breaker.
- Mounts on a bracket inside the enclosure.
Available Models
All Model RXT transfer switches are standard-transition 60 Hz automatic transfer switches. Letters in parentheses refer to the model designation code described on the last page.
| Amps | Description (Connections) | Voltages | Poles | Phases | WCR § RMS Symmetrical Amps |
|---|---|---|---|---|---|
| 100 | Standard (A) | 208 (C) • 240 (F) • | 2 (N) | 1 | 10,000 |
| Standard, with 16-space load center (B) | 240 (F) • | 2 (N) | 1 | 10,000 | |
| Standard, with 12-space load center ** | 240 (F) • | 2 (N) | 1 | 10,000 | |
| Service entrance (ASE, CSE) | 208 (C) • 240 (F) • | 2 (N) | 1 | 22,000 | |
| 150 | Standard, 3-phase (A) | 208 (C) • 240 (F) • 480 (M) • | 3 (T) or 4 (V) | 3 | 30,000 |
| Service entrance (ASE) | 240 (F) • | 2 (N) | 1 | 22,000 | |
| 200 | Standard (A) | 240 (F) • | 2 (N) | 1 | 10,000 |
| Service entrance (ASE, CSE) | 208 (C) • 240 (F) • | 2 (N) | 1 | 22,000 | |
| 300 | Standard, 3-phase (A) | 208 (C) • 240 (F) • 480 (M) • | 3 (T) or 4 (V) | 3 | 30,000 |
| Service entrance (ASE) | 240 (F) • | 2 (N) | 1 | 35,000 | |
| 400 | Standard (A) | 240 (F) • | 2 (N) | 1 | 50,000 |
| Service entrance (ASE) | 240 (F) • | 2 (N) | 1 | 35,000 | |
| Standard, 3-phase (A) | 208 (C) • 240 (F) • 480 (M) • | 3 (T) or 4 (V) | 3 | 50,000 |
§ Withstand and close-on rating. See pages 3-5 for WCR information and specific breaker ratings.
W With 16-space load center and NEMA 1 or NEMA 3R enclosure. Up to 8 tandem breakers can be used, for a maximum of 24 circuits.
** GM85273-SA_ with 12-space load center and NEMA 1 enclosure.
Note: Combined interface board is available on single-phase standard or service entrance models. (Not available on 3-phase or load center models.)
Model Designation
The transfer switch model designation defines ratings and characteristics. Record the transfer switch model designation in the boxes provided.
Sample Model Designation: RXT-JFNC-0200A
Model Breakdown:
- Model: RXT: Kohler Automatic Transfer Switch
- Controls: J: Interface for RDC2/DC2 Controller (standard or combined interface/load management)
- 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:
- A: NEMA 1 *
- C: NEMA 3R
* NEMA 1 enclosure is available on 100 amp load center models only.
- Current Rating:
- 0100: 100 amps
- 0150: 150 amps
- 0200: 200 amps
- 0300: 300 amps
- 0400: 400 amps
- Connections:
- A: No load center
- B: With load center (100 amp single-phase only)
- ASE: Service entrance rated
- CSE: Service entrance rated with CSA certification (100/200 amps only)
