Eaton B27CGF30B040 Magnetic Motor Starter | 5HP 230V Single Phase | 30A Contactor with 24-40A Adjustable Overload
The Eaton B27CGF30B040 is a definite purpose magnetic motor starter designed to protect 5HP single-phase air compressor motors from overloads while providing reliable on/off control through your existing pressure switch.
It combines a 30A contactor with adjustable overload protection (24-40A) and features UL Recognized, CSA Certified components in a NEMA Type 1 enclosure. Made in USA. FREE SHIPPING
Solves Pressure Switch Contact Burnout: If your 5HP air compressor pressure switch contacts keep burning out, the Eaton B27CGF30B040 magnetic starter is the permanent solution. It absorbs inrush current and provides overload protection that pressure switches alone cannot deliver.
Common Applications & Use Cases
The B27CGF30B040 is specifically designed for 5HP single-phase motor protection in industrial and commercial compressed air applications.
- Industrial air compressors: 5HP single-phase compressors running on 230V/60Hz power.
- Workshop & garage compressors: Protects expensive motors from overload damage and premature failure.
- Auto body & paint shops: Reliable motor protection for high-duty-cycle compressed air systems.
- Manufacturing facilities: Definite purpose design meets industrial standards for motor control.
- OEM equipment integration: Pre-wired starter simplifies installation in new equipment builds.
Technical Specifications – Eaton B27CGF30B040
| Feature | Details |
|---|---|
| Part Number | B27CGF30B040 |
| Manufacturer | Eaton |
| UPC | 786685458229 |
| Type | Definite Purpose Magnetic Motor Starter |
| Horsepower Rating | 5HP @ 230V Single Phase |
| Coil Voltage | 208-240V AC, 50/60Hz |
| Contactor Rating | 30A Inductive Full Load (IFL) |
| Overload Range | 24-40A Adjustable |
| Overload Type | Bi-Metallic, Ambient Compensated |
| Trip Class | Class 10 |
| Poles | 2 Pole, Non-Reversing |
| Enclosure | NEMA Type 1 |
| Terminals | Box lugs (posidrive setscrew) + quick connect (side-by-side) |
| Dimensions (H × W × D) | 10.17" × 5.63" × 5.81" |
| Weight | 4.8 lbs |
| Certifications | UL Recognized, CSA Certified |
| Warranty | 1 Year Manufacturer (proof of professional install required) |
| Documentation | Download Spec Sheet (PDF) |
| Eaton Internal Reference | 3-4234-0093A |
Professional Installation Required: This starter must be installed by a qualified electrician. Eaton requires proof of professional installation for warranty coverage. Use #10 AWG copper wire minimum for 30A service per NEC. Always consult local electrical codes.
Why Choose Eaton B27CGF30B040?
Industrial-Grade Motor Protection
- Prevents pressure switch burnout: Takes the load off your pressure switch contacts, extending switch life.
- Overload protection: Bi-metallic overload relay protects motor windings from overheating and damage.
- Trip-free mechanism: Cannot be held closed during an overload condition – ensures safe operation.
- Shrouded terminals: Finger-proof design reduces risk of accidental electric shock during service.
- Ambient compensated: Overload adjusts for temperature changes, providing consistent protection.
- No heater elements required: Simplified maintenance and improved reliability.
- Pre-wired from factory: Reduces installation time and wiring errors.
- IEC & UL rated components: Meets rigorous industrial motor control standards.
How the B27CGF30B040 Works with Your Air Compressor
If you are using this starter on an air compressor, you will also need a pressure switch to control the starter. Here's how the system works:
- Pressure switch monitors tank pressure and sends control voltage (208-240V) to the starter coil when the compressor needs to run.
- Starter coil energizes the 30A contactor, which closes the contacts and supplies power to the 5HP motor.
- Overload relay continuously monitors motor current (24-40A adjustable range) and protects against overheating.
- When tank reaches cutout pressure, pressure switch de-energizes the coil and the contactor opens, stopping the motor.
Think of it as a surge protector for your compressor motor – the magnetic starter absorbs incoming power surges and provides overload protection that basic pressure switches cannot deliver.
Related Eaton Magnetic Starters
| Eaton Model | HP Rating | Voltage/Phase | Overload Range |
|---|---|---|---|
| B27CGF30B040 | 5HP | 230V Single Phase | 24-40A |
Frequently Asked Questions
Q: Do I need a separate pressure switch?
A: Yes – This starter works with your existing pressure switch. The switch controls the starter coil (208-240V), which engages the contactor to power the motor.
Q: What's the difference between a magnetic starter and a pressure switch?
A: Pressure switches provide basic on/off control but lack overload protection and cannot handle high inrush currents. Magnetic starters add a contactor plus overload relay for complete motor safeguarding against surges, overheating, and electrical faults.
Q: Can I install this myself?
A: Professional installation is strongly recommended. Eaton requires proof of qualified installation for warranty coverage. Incorrect wiring voids warranty and creates serious safety hazards.
Q: Is this compatible with 3-phase motors?
A: No – This B27CGF30B040 model is designed specifically for single-phase 5HP motors at 230V. For 3-phase applications, see our A27 series starters listed above.
Q: What wire size should I use?
A: Use #10 AWG copper minimum for 30A service per NEC. Always consult local electrical codes and a licensed electrician.
Q: Does it include mounting hardware?
A: Yes – Comes complete with NEMA 1 enclosure ready for wall or surface mounting.
Q: Do you offer free shipping?
A: Yes – This product qualifies for free shipping. See our shipping policy for details.
Q: Where can I find the complete technical specifications?
A: Download the official Eaton B27CGF30B040 Specification Sheet (PDF) for detailed electrical ratings, dimensions, and installation guidelines.
Genuine Eaton Product – Made in USA
Eaton B27 Series magnetic motor starters feature UL Recognized and CSA Certified components designed to meet IEC and UL horsepower ratings for industrial motor control. Eaton's definite purpose starters are engineered for air compressors, HVACR, and demanding motor control applications.
