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IMO UB10D3025A 25A UL 489 Circuit Breaker, 3-pole, D Curve, 10kA
25A 3-pole D-curve miniature circuit breaker with thermo-magnetic protection, 10kA breaking capacity, DIN-rail mounting, and UL 489 approval.
Why Choose the IMO UB10D3025A Circuit Breaker?
The IMO Precision Controls UB10D3025A is a 25A 3-pole miniature circuit breaker for three-phase industrial equipment branches engineered for 25A protection and substantial inrush. It is rated for 480Y/277V AC and provides UL 489 branch-circuit protection in industrial control panels, machinery, and distribution equipment when applied within its electrical ratings.
Thermo-magnetic operation combines a thermal response for sustained overloads with rapid magnetic response during severe faults. The D curve delays magnetic tripping until a higher multiple of rated current, helping prevent nuisance trips on loads with brief, high startup current. A contact-position indicator provides a clear visual reference during inspection and troubleshooting.
⚡ 25A Rating
Protects a correctly sized 3-pole branch circuit rated for 25A
📉 D Trip Curve
10–20 × In magnetic range supports loads with high startup current
🛡️ 10kA Capacity
Provides 10kA short-circuit breaking capacity for suitable electrical systems
✅ UL 489 Approved
Approved for branch-circuit protection when selected and installed correctly
⚠️ Coordinate the 25A 3-pole Breaker with the Load
Confirm the 25A rating, 3-pole configuration, conductor current, 480Y/277V AC rating, available fault current, D trip curve, ambient conditions, and equipment requirements before installation. A D-curve breaker does not replace separate motor-overload protection when the equipment or applicable code requires it.
📋 25A D-Curve Magnetic Trip Range
The D-curve magnetic element operates at 10–20 times rated current. For the UB10D3025A, this corresponds to an instantaneous magnetic range of approximately 250–500A. The thermal element responds to sustained overloads. Confirm coordination with normal startup current and upstream or downstream protective devices.
Key Features & Benefits
- 3-pole DIN-rail mounting configuration
- Rated for 480Y/277V AC
- Approximate magnetic trip range of 250–500A
- Thermo-magnetic overload and short-circuit protection
- Contact-position indicator for visual status checks
- 18–3 AWG conductor range with 2.5 Nm fastening torque
- UL 489, IEC 60947-2, IEC 60898-1, and RoHS compliance
Technical Specifications
| Dimensions |
4.25" Length x 2.06" Width x 2.64" Depth (108mm x 52.5mm x 67mm) |
| Rated Current |
25 Amp |
| Voltage Rating |
480Y / 277V AC |
| Number of Poles |
3 |
| Tripping Curve |
D (10-20 In) |
| Calibration Temperature |
104 F (40 C) |
| Operating Temperature |
-13 F to 131 F (-25 C to 55 C) |
| Rated Operational Frequency |
50/60 Hz |
| Short Circuit Breaking Capacity |
10kA |
| Lifespan |
20,000 Operations (Mechanical), 6000 Operations (Electrical) |
| Vibration Resistance |
+/- 1mm @ 5-25 Hz; 50 m/s² @ 25-150 Hz |
| Fastening Torque |
2.5 Nm (22.2 lb/in) |
| Wire Range |
18-3 AWG |
| NEMA Rating |
NEMA 1 (IP20 - Protection from objects 12.5 mm (0.5") in diameter or greater) |
| Approvals |
UL 489, IEC 60947-2 & IEC 60898-1, RoHS Compliant |
📋 3-pole Breaker Selection and Installation Overview
1. Calculate the Load: Confirm that conductor current and connected equipment are compatible with a 25A protective device.
2. Verify Pole and Voltage Requirements: Confirm that the circuit requires 3 poles and operates within the 480Y/277V AC rating.
3. Check Fault and Inrush Current: Verify the available fault current, 10kA breaking capacity, and compatibility of the D curve with normal startup demand.
4. Mount and Terminate: Install on DIN rail using conductors within the specified 18–3 AWG range and apply the listed 2.5 Nm terminal torque.
5. Inspect Before Energizing: Verify wiring, labeling, protective-device coordination, and code compliance before commissioning.
Circuit-breaker selection and installation must be completed by qualified personnel in accordance with the equipment documentation and applicable electrical codes.
🏭 Typical Uses for the 25A 3-pole D-Curve Breaker
• Three-phase machinery branches
• Industrial transformer and conversion equipment
• High-inrush equipment circuits
• Three-pole AC circuits requiring 25A D-curve protection
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