AC 4 Pole Molded Case Circuit Breaker 225A

What Is a AC 4 Pole Molded Case Circuit Breaker 225A?

The AC 4 Pole Molded Case Circuit Breaker 225A is a specialized electrical protection device designed to safeguard three-phase circuits with a neutral line (L1, L2, L3, N). Rated for 225 Amperes, it serves as a core component for intermediate power distribution, protecting downstream equipment from overloads and short circuits while ensuring total system isolation.

How It Works, Operates, and Debugs

Operational Mechanism

The unit features a clear, responsive manual operating mechanism with distinct tactile feedback. The handle positions are explicitly marked:

• ON: Circuit is closed and energized.
• OFF: Circuit is open and de-energized.
• TRIPPED: Intermediate position indicating a fault has occurred.

Working Principle

AC 4 Pole Molded Case Circuit Breaker 225A utilizes a thermal-magnetic trip unit for dual-layer protection:

• Thermal Protection (Overload): Uses a bimetallic element to provide inverse-time tripping. The higher the overload current, the faster the trip.
• Magnetic Protection (Short Circuit): Provides an instantaneous response to clear high-magnitude fault currents (up to tens of kA) immediately.

Commissioning & Accessories

The series offers strong expandability for specific application needs. Commissioning involves installing the required add-ons into the designated slots:

• Auxiliary Contacts: For remote signaling of the breaker's status.
• Shunt Release: Allows for remote tripping/opening of the breaker.
• Undervoltage Release: Automatically trips the breaker if voltage drops below a safe level.
• RCD Module: Adds earth leakage protection for comprehensive safety.

Key Technical Features and Specifications

Capacity

Rated current of 225A, suitable for intermediate distribution loads.

Poles

4-Pole (4P): Protects three phases plus the neutral, ensuring complete isolation of the circuit.

Voltage

Designed for standard AC distribution networks (typically 400V/690V AC).

Trip Unit

Standard Thermal-Magnetic unit with adjustable or fixed settings depending on the model variant.

Interrupt Ratings

High short-circuit breaking capacity (Icu) capable of handling tens of kiloamperes safely.

Mounting

Utilizes secure bolted connections, ensuring a reliable electrical interface for high-current applications.

Construction

Robust molded case design that is impact-resistant and dimensionally stable.

Quality Assurance & Delivery

At Pugao Electric, our principle is "preventing defects from progressing to the next stage."

• 100% Inspection: Every unit undergoes mechanical, electrical, and environmental testing before shipment.
• Export-Grade Packaging: AC 4 Pole Molded Case Circuit Breaker 225A is secured to withstand long-distance handling.
• Fast Delivery: Regular models are often available from inventory, while customized orders follow a confirmed production timeline.

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Product specification

FAQ

Why use a 4-Pole instead of a 3-Pole?

A 4-pole breaker disconnects all three phases and the neutral conductor simultaneously. This is essential for:

• Safety: Ensures total isolation of the circuit for maintenance personnel.
• Backup Power Systems: Required for transfer switches (ATS) to prevent neutral-to-ground loops when switching between utility and generator power.
• Harmonic Mitigation: Protects against neutral currents caused by non-linear loads (like VFDs and computers).

What is the voltage rating?

The AC 4 Pole Molded Case Circuit Breaker 225A is typically rated for standard industrial distribution voltages, commonly supporting 400V to 690V AC systems. Please refer to the specific nameplate on the unit for the exact rated operational voltage (Ue) and insulation voltage (Ui).

What is the Trip Unit Type?

Standard models utilize a Thermal-Magnetic Trip Unit:

• Thermal: Provides inverse-time protection against overloads using a bimetallic strip.
• Magnetic: Provides instantaneous protection against short circuits.

Note: Electronic trip units may be available for more precise settings.

What is the breaking capacity?

The breaking capacity (Icu) varies by specific model variant but is designed to handle significant fault currents typical of intermediate distribution. The AC 4 Pole Molded Case Circuit Breaker 225A generally offers a breaking capacity ranging from 25kA up to 85kA (at 400V), ensuring it can safely interrupt short circuits without damage.