Cummins OTEC Spec C 277/480V 3-Phase 4-Pole 125A Transfer Switch
125A, 277/480V, four-pole open-transition ATS for commercial and light industrial standby power. Electrically operated, mechanically held, break-before-make switching with dual mechanical and electrical interlocking. 4-pole design switches all three phase conductors plus neutral — required for separately derived systems. NEMA 1 enclosure rated for indoor installation. Not service rated — upstream overcurrent protection required.
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
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 all three phases on both sources. 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.
4-Pole Switching Switches neutral and all three phase conductors simultaneously. Meets NEC 700, 701, and 702 requirements for separately derived systems.
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 1 Indoor Enclosure Rated for clean, dry indoor environments. Suitable for electrical rooms, mechanical spaces, and similar protected locations.
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 | 277/480V, 3Ø, 4-Pole, 60 Hz |
| Amperage | 125A |
| Enclosure | NEMA 1 Indoor |
| 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 | Not Service Rated |
| Certification | UL 1008 |
Warranty
One-year Cummins limited warranty. Covers unit, contact assemblies, and PC40-11 control. Service through authorized Cummins distributors.
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 277/480V 3-Phase 4-Pole 125A Transfer Switch
125A, 277/480V, four-pole open-transition ATS for commercial and light industrial standby power. Electrically operated, mechanically held, break-before-make switching with dual mechanical and electrical interlocking. 4-pole design switches all three phase conductors plus neutral — required for separately derived systems. NEMA 1 enclosure rated for indoor installation. Not service rated — upstream overcurrent protection required.
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
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 all three phases on both sources. 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.
4-Pole Switching Switches neutral and all three phase conductors simultaneously. Meets NEC 700, 701, and 702 requirements for separately derived systems.
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 1 Indoor Enclosure Rated for clean, dry indoor environments. Suitable for electrical rooms, mechanical spaces, and similar protected locations.
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 | 277/480V, 3Ø, 4-Pole, 60 Hz |
| Amperage | 125A |
| Enclosure | NEMA 1 Indoor |
| 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 | Not Service Rated |
| Certification | UL 1008 |
Warranty
One-year Cummins limited warranty. Covers unit, contact assemblies, and PC40-11 control. Service through authorized Cummins distributors.
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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