Kohler KSSB Series Automatic Transfer Switches
Model KSSB - Standard Specific Breaker Rated
Product Overview
The Kohler KSSB Series Automatic Transfer Switches are designed for reliable and safe transfer of electrical loads between a primary power source and a standby power source. These switches are suitable for emergency and standby applications in commercial and industrial settings.
Image Description: A tall, rectangular, gray electrical enclosure with "KOHLER" branding, representing the KSSB transfer switch unit.
Key Features
- UL 1008 listed ✔️ (file #E58962 automatic, #E86894 nonautomatic)
- CSA certification available ✔️
- IBC seismic certification available ✔️
- Available in 2, 3, or 4 pole configurations
- Electrically operated, mechanically held mechanism ⚙️
- High withstand and close-on ratings
- Suitable for emergency and standby applications on all classes of load
- 100% tungsten rated through 400 amps
- Silver alloy main contacts
- Gold-flashed engine start contacts (rated 2 amps @ 30 VDC/250 VAC)
- Front-accessible contacts for easy inspection
- Front-replaceable main and arcing contacts (800-1200 amps)
- Reliable, field-proven solenoid mechanism
- Switching mechanisms lubricated for extended life
- Internal manual operating handle
- Main shaft auxiliary position-indicating contacts (rated 10 amps @ 32 VDC/250 VAC)
- NEMA type 1, 12, 3R, 4, and 4X enclosures available ?
- Standard one-year limited warranty ?️. Extended limited warranties are available.
- Standard-transition operation with either automatic or non-automatic control
- Standard-transition transfer time less than 100 milliseconds (6 cycles @ 60 Hz)
- Double-throw, mechanically interlocked design (break-before-make power contacts) ⚙️
- Solid, switched, or overlapping (make-before-break) neutral options
Available Controllers
Decision-Maker® MPAC 1200 Controller
Image Description: A close-up of the KOHLER Decision-Maker MPAC 1200 controller, showing an LCD screen, buttons, and indicator lights.
- LCD display, 4 lines x 20 characters, backlit ?️
- Complete programming and viewing capability via keypad and LCD display
- LED indicators: Source available, transfer switch position, service required (fault), and "not in auto" ?
- Programmable voltage and frequency pickup and dropout settings ⚡
- Programmable time delays ⏳
- Programmable generator exerciser ⚙️
- Time-based load control
- Two programmable inputs and two programmable outputs ?
- Up to four I/O extension modules available
- Modbus communication standard ?
- RS-485 communication standard ?
- Ethernet communication optional ?
For more information, refer to specification sheet G11-127.
Ratings
| Current | Voltage | Frequency |
|---|---|---|
| 30-1200 amps | 208-600 VAC | 50/60 Hz |
Application Data
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 |
Input and Output Connection Specifications
| Component | Wire Size Range ? |
|---|---|
| Main board I/O terminals | #12-24 AWG |
| I/O module terminals | #14-24 AWG |
Auxiliary Position Indicating Contacts
(rated 10 amps @ 32 VDC/250 VAC)
| Switch Rating, Amps | Number of Contacts Indicating Normal, Emergency |
|---|---|
| 30-230 | 2, 2 |
| 260-1200 | 8, 8 |
Cable Sizes
Note: Cable size data is subject to change. Refer to the transfer switch dimension drawings and wiring diagrams for planning and installation. ?
UL-Listed Solderless Screw-Type Terminals for External Power Connections
| Model | Switch Rating, Amps | Range of Wire Sizes, Copper or Aluminum * | ||
|---|---|---|---|---|
| Normal, Emergency, and Load (per phase) | Neutral (3-pole) | Ground | ||
| KSS | 30-150 | (1) #14 AWG to 4/0 AWG | (3) #14 to 4/0 AWG | (3) #6 to 3/0 AWG |
| 200 | (1) #14 AWG to 4/0 AWG Cu only | (3) #14 to 4/0 AWG Cu only | (3) #6 to 3/0AWG | |
| 230 (208-480 V) | (1) #4 AWG to 600 KCMIL or (2) 1/0 AWG to 250 KCMIL | (3) #4 AWG to 600 KCMIL or (6) 1/0 AWG to 250 KCMIL | (3) #4 AWG to 600 KCMIL or (6) 1/0 AWG to 250 KCMIL | |
| 230 (600 V) / 260-400 | (2) #2 AWG to 600 KCMIL | (6) #2 AWG to 600 KCMIL | (3) #4 AWG to 600 KCMIL or (6) 1/0 to 250 KCMIL | |
| 600 | (4) 1/0 AWG to 750 KCMIL | (12) 1/0 AWG to 750 KCMIL | (3) #4 AWG to 500 KCMIL | |
| 800-1000 | (4) 1/0 AWG to 750 KCMIL | (12) 1/0 AWG to 750 KCMIL | (3) #4 AWG to 500 KCMIL | |
| 1200 (NEMA 3R) | (4) 1/0 AWG to 750 KCMIL | (12) 1/0 AWG to 750 KCMIL | (3) #4 AWG to 500 KCMIL | |
| 1200 (NEMA 1) | (4) 1/0 AWG to 750 KCMIL | (12) 1/0 AWG to 750 KCMIL | (3) #4 AWG to 500 KCMIL | |
⚠️ Use 75°C minimum Cu/Al wire for power connections.
Weights and Dimensions
Note: Always use the transfer switch dimension drawing for planning and installation. Weights and dimensions may vary for different configurations. See your local distributor for dimension drawings. ?
Weights and dimensions are shown for NEMA Type 1 enclosures, NEMA Type 3R enclosures and open units. See the transfer switch dimension drawings for other enclosure types.
| Model | Amps | NEMA Type | Poles | Wires | Dimensions mm (in.) | Weight kg (lb.) | Dimension Drawing | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Height | Width | Depth | 2-Pole | 3-Pole | 4-Pole | ||||||
| KSS | 30-200 | 2,3,4 | 3, 4 | 791 (31) | 450 (18) | 314 (12.4) | 28 (62) | 30 (65) | 31 (68) | ADV-8566 | |
| 230 (208-480V) | 2,3,4 | 3, 4 | 1223 (48) | 560 (22) | 362 (14.3) | 52 (115) | 56 (123) | 59 (131) | ADV-8568 | ||
| 230 (600 V) / 260-600 | 1, 3R | 2,3,4 | 3, 4 | 1702 (67) | 610 (24) | 514 (20.2) | 179 (395) | 183 (403) | 188 (414) | ADV-8570 | |
| 800 | 2,3,4 | 3, 4 | 1932 (76)* | 864 (34) | 515 (20.3) | 220 (485) | 231 (510) | 238 (525) | ADV-8572 | ||
| 1000 | 3,4 | 4 | 1932 (76)* | 864 (34) | 515 (20.3) | — | 231 (510) | 238 (525) | ADV-8572 | ||
| 1200 (NEMA 3R) | 3R | 3,4 | 4 | 2286 (90) | 963 (38) | 688 (27.1) | — | 356 (785) | 379 (835) | ADV-8574 | |
| 1200 (NEMA 1) | 1 | 3,4 | 4 | 2286 (90) | 940 (37) | 717 (28.2) | — | 356 (785) | 379 (835) | ADV-8575 | |
| KSS (Open Unit) | 30-200 | 2,3,4 | 3, 4 | 787 (31) | 445 (18) | 296 (11.6) | 8 (17) | 9 (20) | 11 (23) | ||
| 230 (208-480V) | 2,3,4 | 3, 4 | 1219 (48) | 457 (18) | 330 (13.0) | 17 (37) | 21 (45) | 24 (53) | |||
| 230 (600V) / 260-600 | Open Unit § | 2,3,4 | 3, 4 | 1422 (56) | 610 (24) | 362 (14.3) | 31 (68) | 34 (74) | 36 (80) | ADV-7182 | |
| 800 | 2,3,4 | 3, 4 | 1829 (72) | 864 (34) | 508 (20) | 68 (150) | 78 (170) | 90 (196) | |||
| 1000 | 3,4 | 4 | 1829 (72) | 864 (34) | 508 (20) | — | 78 (170) | 90 (196) | |||
| 1200 | 3,4 | 4 | 2210 (87) | 965 (38) | 584 (23) | — | 78 (170) | 90 (196) | |||
⚠️ Includes mounting feet
§ On 30-1000 amp models, the NEMA type 3R enclosures have a security cover on the controller that extends 54 mm (2.1 in.) beyond the door.
Dimensions shown for open units are the minimum required enclosure size. Open unit weights are shipping weights for the contactor only.
Withstand and Close-On Ratings (WCR)
The following tables provide Withstand and Close-On Ratings (WCR) in RMS symmetrical amperes for standard, programmed, and closed-transition models. These ratings are for current coordinated with customer-supplied fuses or circuit breakers and are tested in accordance with UL 1008 requirements. Application requirements may permit higher withstand ratings for certain size switches; contact the factory for assistance.
Note: The extensive tables detailing specific circuit breaker and fuse ratings have been summarized to maintain conciseness. For complete details, please refer to the original document or contact Kohler.
Summary of WCR
Kohler KSSB transfer switches are available with high withstand and close-on ratings, coordinated with various current-limiting fuses and specific manufacturers' molded-case circuit breakers. Ratings vary significantly based on the switch rating, voltage, and the type/size of the protective device used.
For example, a 30-amp KSS switch can have a 480V Max withstand rating of 100kA when coordinated with specific breakers, while a 1200-amp switch can achieve ratings up to 200kA at 200kA (RMS symmetrical amperes).
Detailed tables for specific manufacturers like GE, Square D, Eaton/Cutler Hammer, and Siemens/ITE are available in the original document, listing WCR for various models and their compatible circuit breakers.
Codes and Standards
The ATS meets or exceeds the requirements of the following specifications:
- CSA C22.2 No. 178 certification available, file #LR58301
- EN61000-4-4 Fast Transient Immunity Severity Level 4
- EN61000-4-5 Surge Immunity Class 4 (voltage sensing and programmable inputs only)
- IEC Specifications for EMI/EMC Immunity: CISPR 11, IEC 1000-4-2, IEC 1000-4-3, IEC 1000-4-4, IEC 1000-4-5, IEC 1000-4-6, IEC 1000-4-8, IEC 1000-4-11
- IEEE Standard 446, IEEE Recommended Practice for Emergency and Standby Power Systems for Commercial and Industrial Applications
- IEEE 472 (ANSI C37.90A) Ring Wave Test
- NEMA Standard ICS 10-2005, Electromechanical AC Transfer Switch Equipment
- NFPA 70, National Electrical Code
- NFPA 99, Essential Electrical Systems for Health Care Facilities
- NFPA 110, Emergency and Standby Power Systems
- Seismic certification in accordance with the International Building Code is available (Accessory kit required). Includes IBC 2000, 2003, 2006, 2009, 2012 referencing ASCE 7 and ICC AC-156.
- Underwriters Laboratories UL 1008, Standard for Automatic Transfer Switches for Use in Emergency Standby Systems, file #E58962 (automatic), #E86894 (nonautomatic)
Accessories and Options
Controller Accessories
- Alarm Module
- External Battery Supply Module
- Input/Output Module
- High-Power Input/Output Module
- Controller Disconnect Switch
- Ethernet Communications
- Current Sensing Kit
- Padlockable User Interface Cover
- Supervised Transfer Control Switch
Transfer Switch Accessories
- CSA Certification
- Digital Meter (measures voltage, current, frequency, power; 35 programmable alarms; LCD display; pushbutton operation; password-protected menus; digital inputs/outputs; Form A relay outputs; serial port; data logging)
- Engine Start Circuit Monitor (See Specification Sheet G6-165)
- Export Packaging (10-year major components)
- Extended Limited Warranties (2-year basic, 5-year basic, 5-year comprehensive)
Heater, Anti-Condensation
- Hygrostat-controlled 120 VAC strip heater (customer-supplied voltage source required)
- 100 or 250 watts (sized for enclosure)
- Protective 15 Amp circuit breaker
Literature Kits
- Production literature kit (one set included with each transfer switch)
- Overhaul literature kit
RSA III Remote Serial Annunciator
- Monitors generator set, Normal and Emergency source status/connection, ATS common alarm
- Allows remote testing of the ATS
- For more information, see specification sheet G6-139.
Surge Protection Device (SPD)
SPD available for the normal source supply. Surge protection reduces transient voltages to harmless levels.
- Protection modes: L-L / L-N / L-G / N-G
- Replaceable phase and neutral cartridges
- Frequency: 50-60 Hz
- Operating Temperature Range: -40 to 176°F (-40 to 80°C) ?️
- Remote contacts for customer-supplied status indicators (1 NO, 1 NC)
- Fuse protection: 30 amps / 600 V
- UL 1449, 3rd Edition for Type 2 applications
- IEC 61-643-1, 2nd Edition T2/11
SPD Specifications
| Nominal Voltage (V ±15%) | Max. Discharge Current (kA) | Phase | Poles | UL VPR 3rd Ed (L-N/N-G/L-G) (kV) | Limiting Voltage, (L-N/N-G/L-G) (kV) | Short Circuit Withstand Current (kA) | Maximum Continuous Operating Voltage (VAC) | |
|---|---|---|---|---|---|---|---|---|
| at 3kAmps | at 10kAmp | |||||||
| 240/120 | 40 | Split | 3 | 0.6/1.2/0.7 | 0.6/0.4/0.6 | 0.8/0.7/0.8 | 200 | 175/350 |
| 208/120 | 40 | Wye | 4 | 0.6/1.2/0.7 | 0.6/0.4/0.6 | 0.8/0.7/0.8 | 200 | 175/350 |
| 480/277 | 40 | Wye | 4 | 1.0/1.2/1.1 | 1.0/0.4/1.0 | 1.2/0.7/1.2 | 200 | 320/640 |
| 240/120 | 40 | HLD | 4 | 1.0/1.2/1.1 | 1.0/0.4/1.0 | 1.2/0.7/1.2 | 200 | 320/640 |
| 600/347 | 40 | Wye | 4 | 1.3/1.2/1.4 | 1.3/0.4/1.3 | 1.5/0.7/1.5 | 200 | 440/880 |
Seismic Certification
IBC Seismic Certification is available and depends on application and geographic location. Contact your distributor for details. Available for all KSS enclosures.
Model Designation
The transfer switch model designation defines characteristics and ratings. The format is generally KSS-AMTA-XXXX, where components are defined as follows:
| Model: K = Kohler | Mechanism: S = Standard (Specific Breaker) |
| Transition: S = Standard | Controller: A = Decision-Maker® MPAC 1200, Automatic; B = Decision-Maker® MPAC 1200, Non-Automatic |
| Voltage/Frequency: C=208V/60Hz, D=220V/50Hz, F=240V/60Hz, G=380V/50Hz, H=400V/50Hz, J=416V/50Hz, K=440V/60Hz, M=480V/60Hz, N=600V/60Hz, P=380V/60Hz, R=220V/60Hz, S=400V/60Hz | Number of Poles/Wires: N=2 Pole/3 Wire, T=3 Pole/4 Wire, V=4 Pole/4 Wire Switched, W=4 Pole/4 Wire Overlapping |
| Enclosure: A=NEMA 1, B=NEMA 12, C=NEMA 3R, D=NEMA 4, F=NEMA 4X, G=Open Unit | Current, Amps: 0030, 0070, 0104, 0150, 0200, 0230, 0260, 0400, 0600, 0800, 1000, 1200 |
| Connections: S = Standard |
Sample Model Designation: KSS-AMTA-0400S
Note: Some selections are not available for every model. Contact your Kohler distributor for availability. ?
