Cummins OTEC Spec C 120/240V Single-Phase 225A Service Rated Transfer Switch
225A, 120/240V, single-phase open-transition ATS rated for service entrance installation. Electrically operated, mechanically held, break-before-make switching with dual mechanical and electrical interlocking. Service rated — can be installed at the service entrance without additional upstream overcurrent protection. NEMA 3R enclosure rated for indoor and outdoor installation.
Breaker Rating Update — September 2025: Cummins issued revised Withstand Closing Breaker Ratings for the Spec C family. UL and CUL listing confirmed August 14, 2025. AHJ documentation available in PDFs below.
Features & Benefits
Service Entrance Rated Listed for installation at the service entrance. No separate main disconnect required upstream. Simplifies installation and reduces overall equipment cost on qualifying projects.
PC40-11 Controller Microprocessor-based. Backlit LCD. Soft-touch keypad. Front panel or PC configuration. Ships with Modbus RTU and TCP. Configurable I/O. Programmable exercise scheduler included.
Voltage Imbalance Sensing Monitors both sources continuously. Catches imbalance conditions beyond standard over/under voltage limits.
Phase Rotation Monitoring Confirms correct phase sequence on both sources before every transfer. Blocks transfer to a miswired or out-of-sequence source.
Contact Assembly Silver alloy main contacts under high closing pressure. Dedicated arcing contacts protect main contacts from switching wear. Multi-layer arc chutes extinguish arcs after each operation. UL 1008 certified — contacts included.
NEMA 3R Enclosure Rated for rain, sleet, and external ice. Suitable for rooftops, outdoor generator pads, and exposed mechanical spaces.
Field-Install Options Remote annunciator — Load shedding — Integral control power supply — Ethernet/Modbus TCP module — Anticondensation heater — Auxiliary contact expansion (8 or 16 configurable contact sets)
Specifications
| Voltage | 120/240V, Single-Phase, 60 Hz |
| Amperage | 225A |
| Enclosure | NEMA 3R Indoor/Outdoor |
| Controller | PowerCommand PC40-11 |
| Transition | Open Delayed; Open-In-Phase |
| Transfer Time | ≤6 cycles / 60 Hz |
| Neutral Bar | Full-rated with lugs |
| Aux Contacts | 2x isolated N/O, 10A/250V |
| Surge Compliance | IEEE C62.41 / C62.42 |
| Arc Interruption | Multi-layer arc chute assembly |
| Manual Override | Yes — all sources de-energized |
| Service Rating | Service Entrance Rated |
| Certification | UL 1008 |
Warranty
One-year Cummins limited warranty. Covers unit, contact assemblies, and PC40-11 control.
Payment & Security
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
Cummins OTEC Spec C 120/240V Single-Phase 225A Service Rated Transfer Switch
225A, 120/240V, single-phase open-transition ATS rated for service entrance installation. Electrically operated, mechanically held, break-before-make switching with dual mechanical and electrical interlocking. Service rated — can be installed at the service entrance without additional upstream overcurrent protection. NEMA 3R enclosure rated for indoor and outdoor installation.
Breaker Rating Update — September 2025: Cummins issued revised Withstand Closing Breaker Ratings for the Spec C family. UL and CUL listing confirmed August 14, 2025. AHJ documentation available in PDFs below.
Features & Benefits
Service Entrance Rated Listed for installation at the service entrance. No separate main disconnect required upstream. Simplifies installation and reduces overall equipment cost on qualifying projects.
PC40-11 Controller Microprocessor-based. Backlit LCD. Soft-touch keypad. Front panel or PC configuration. Ships with Modbus RTU and TCP. Configurable I/O. Programmable exercise scheduler included.
Voltage Imbalance Sensing Monitors both sources continuously. Catches imbalance conditions beyond standard over/under voltage limits.
Phase Rotation Monitoring Confirms correct phase sequence on both sources before every transfer. Blocks transfer to a miswired or out-of-sequence source.
Contact Assembly Silver alloy main contacts under high closing pressure. Dedicated arcing contacts protect main contacts from switching wear. Multi-layer arc chutes extinguish arcs after each operation. UL 1008 certified — contacts included.
NEMA 3R Enclosure Rated for rain, sleet, and external ice. Suitable for rooftops, outdoor generator pads, and exposed mechanical spaces.
Field-Install Options Remote annunciator — Load shedding — Integral control power supply — Ethernet/Modbus TCP module — Anticondensation heater — Auxiliary contact expansion (8 or 16 configurable contact sets)
Specifications
| Voltage | 120/240V, Single-Phase, 60 Hz |
| Amperage | 225A |
| Enclosure | NEMA 3R Indoor/Outdoor |
| Controller | PowerCommand PC40-11 |
| Transition | Open Delayed; Open-In-Phase |
| Transfer Time | ≤6 cycles / 60 Hz |
| Neutral Bar | Full-rated with lugs |
| Aux Contacts | 2x isolated N/O, 10A/250V |
| Surge Compliance | IEEE C62.41 / C62.42 |
| Arc Interruption | Multi-layer arc chute assembly |
| Manual Override | Yes — all sources de-energized |
| Service Rating | Service Entrance Rated |
| Certification | UL 1008 |
Warranty
One-year Cummins limited warranty. Covers unit, contact assemblies, and PC40-11 control.
Payment & Security
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
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