ABB T3N225 Molded Case Circuit Breaker (MCCB)

Technical Specifications

• Product Series: ABB Tmax T3 Series (Successor to SACE Tmax)
• Breaker Type: Molded Case Circuit Breaker (MCCB)
• Rated Current (In): 225 A (Standard)
• Rated Voltage (Ue):
  • AC: Up to 690 V (50/60 Hz)
  • DC: Up to 250 V
• Rated Insulation Voltage (Ui): 690 V AC
• Poles: 3-Pole (3P) or 4-Pole (4P) configurations available
• Breaking Capacity:
  • Rated Ultimate Short-Circuit Breaking Capacity (Icu): Up to 36 kA to 70 kA (depending on specific voltage and configuration)
  • Rated Service Short-Circuit Breaking Capacity (Ics): Typically 50% to 75% of Icu (e.g., 25 kA to 50 kA)
• Trip Unit Types:
  • TMD: Thermo-magnetic, fixed thermal and magnetic trip
  • TMA: Thermo-magnetic, adjustable thermal and fixed magnetic trip
  • PR222MP/LI: Electronic trip unit with adjustable Long-time (L) and Instantaneous (I) protection
• Mounting Type: Fixed, Plug-in (Inserted), or Withdrawable
• Terminal Type: Front connection (F), Rear connection (R), or Cable connection (C)
• Mechanical Life: Up to 20,000 operations
• Electrical Life: Up to 10,000 operations (at rated current)
• Protection Class: IP20 (Finger-safe) for the front panel; IP40 for enclosed installations
• Operating Temperature: -5°C to +40°C (Storage: -40°C to +85°C)
• Standards Compliance: IEC 60947-2, GB 14048.2, UL, CSA, CE

Key Features and Functional Highlights

• Dual Protection Mechanism: Integrates both thermal protection (for overloads) and magnetic protection (for short circuits) in a single unit. The thermal element uses a bimetallic strip that bends under sustained overcurrent, while the magnetic coil triggers instantaneous tripping during high-current faults.
• Adjustable Trip Settings: Depending on the trip unit (TMA or PR222MP), users can adjust the overload current threshold (Ir) and short-circuit delay (tr). This allows for precise coordination with upstream and downstream devices, preventing nuisance tripping.
• High Breaking Capacity: Capable of safely interrupting extremely high fault currents (up to 70 kA) without damage, ensuring system integrity even in severe short-circuit conditions.
• Visual Indication: Clear “ON/OFF” and “TRIPPED” position indicators on the handle, allowing for quick visual status checks of the circuit.
• Accessories and Modularity: Supports a wide range of auxiliary contacts (AUX), shunt trips (for remote opening), under-voltage releases (UVR), and motor operators for remote closing. This modularity makes it adaptable for complex control schemes.
• Isolation Capability: With the addition of an isolator accessory or specific contact configuration, it can function as a main switch for safe maintenance isolation (compliant with isolation standards).
• Robust Construction: Features a thermoset plastic housing that provides high resistance to impact, arc flash, and environmental contaminants. The internal components are designed to withstand high mechanical stress during fault clearing.
• Compliance with Global Standards: Certified for use worldwide, meeting the stringent requirements of IEC, UL, CSA, and CE, making it suitable for export projects and global OEM machinery.

Application Scenarios

The ABB T3N225 is a versatile workhorse deployed across a wide spectrum of critical industries:

• Industrial Manufacturing: Used as the main feeder breaker in factories for protecting motors, transformers, and production lines. It is essential in steel mills, cement plants, and chemical processing facilities where high reliability is required.
• Commercial Buildings: Protects distribution boards in large office complexes, shopping malls, and hotels. It safeguards lighting circuits, HVAC systems, and elevator power supplies from overloads and faults.
• Power Distribution: Serves as a feeder or branch circuit breaker in low-voltage switchgear (LV switchgear) for utility substations and power distribution networks.
• Infrastructure Projects: Widely used in transportation systems (railways, airports), water treatment plants, and data centers to ensure continuous power availability and protect critical assets.
• Renewable Energy: Applied in solar power plants and wind farms for protecting inverters, transformers, and collection systems.
• Marine and Offshore: Utilized in shipboard electrical distribution systems due to its compact size, high breaking capacity, and resistance to vibration and humidity.
• OEM Machinery: Integrated into control panels of large equipment like compressors, pumps, and conveyor systems to provide built-in circuit protection.

Ordering and Identification Information

When specifying or ordering the ABB T3N225, precise configuration is essential:

• Part Number Structure: The full identifier (e.g., 1SDA066721R1 or similar) defines the exact configuration. The “T3N225” prefix indicates the frame size and current rating, while suffixes denote the trip unit, poles, and accessories.
• Trip Unit Selection:
  • TMD: Standard protection, non-adjustable (most economical).
  • TMA: Adjustable overload protection, fixed short-circuit protection.
  • PR222MP: Fully electronic, highly accurate protection with communication capabilities (most advanced).
• Accessories: Must be ordered separately. Common accessories include auxiliary contacts (AUX-C), shunt trip coils (SHT), under-voltage releases (UVR), and rotary handles for front-panel operation.
• Mounting Configuration: Ensure compatibility with the switchgear busbar system (Fixed, Plug-in, or Withdrawable). Mixing incompatible mounting types can lead to installation failures.
• Sourcing: As a legacy but actively supported product, it is crucial to purchase from authorized ABB distributors to ensure genuine parts and valid warranty coverage. Counterfeit breakers pose a significant safety risk in electrical systems.
• Replacement/Upgrade: While the T3N225 is a robust standard, ABB has introduced newer series like XT for next-generation applications. However, the T3N225 remains the preferred choice for retrofits and maintenance of existing Tmax-based installations due to its proven track record and dimensional compatibility.