Eaton BA33A – NEMA A200 Type B Thermal Overload Relay | 3-Pole | 19–90A | Class 20
Eaton BA33A – NEMA A200 Type B Thermal Overload Relay | 3-Pole | 19–90A | Class 20
Product images are representative only. Actual product may vary.
The Eaton BA33A is a NEMA A200 series, Type B, bimetallic thermal overload relay designed to protect three-phase industrial motors across an exceptionally wide current range of 19 to 90 amperes. Built to Class 20 trip standards, it offers reliable overload protection for both single-phase and three-phase applications, making it one of the most versatile overload relays in the Eaton lineup.
Also sold as the Cutler-Hammer BA33A, this relay is a drop-in modern replacement for Type A overload relays in manual reset applications. Its bimetallic, block-type design delivers consistent performance in demanding industrial environments.
Key Specifications
- Part Number: BA33A
- Manufacturer: Eaton (Cutler-Hammer)
- Series: NEMA A200 / Freedom Series
- Relay Type: Thermal, Type B (Bimetallic)
- Trip Class: Class 20
- Poles: 3-Pole
- Full Load Current Range: 19–90A
- Auxiliary Contact: 1NC
- Mounting Type: Starter Mounted
- Ambient Compensation: Yes
- Enclosure Rating: NEMA 5
- Terminal Type: Threaded
- Temperature Range: 40°C to 75°C
- Voltage Rating: 24–600V AC
- NEMA Size: 3
- Certifications: UL Listed, CSA Certified
Why Choose the Eaton BA33A?
- Widest Current Coverage: A 19–90A range covers NEMA Size 3 starters and a broad spectrum of motor HP ratings in a single relay — reducing the number of SKUs you need to stock.
- Type B Bimetallic Design: Modern block-type bimetallic construction provides Class 20 protection in both single- and three-phase applications — more flexible than older eutectic alloy designs.
- Drop-In Type A Replacement: The BA33A is a direct upgrade for Type A (AA-series) overload relays in manual reset mode, including the BA23A and AA23A where range overlap exists.
- Ambient Compensated: Accurate trip performance across a 40–75°C ambient temperature range — ideal for hot panel environments.
- Phase Failure Protection: Single-phase trip detection protects motors from running on two legs, a leading cause of motor burnout.
Typical Applications
- NEMA Size 3 motor starters (25–50 HP at 480V)
- Large pump and compressor motor protection
- Industrial conveyor and material handling drives
- HVAC air handler and chiller motor panels
- Heavy industrial manufacturing equipment
Compatibility & Cross-Reference
The BA33A is compatible with Eaton A200, A210, and A250 NEMA Size 3 motor starters. It ships with a contactor mounting bracket, the overload relay, and connection straps. The BA33A serves as a direct replacement for Type A relays (including AA33A) in 3-pole manual reset configurations.