Product Overview
The EATON PL9-C50/2-DC is a Miniature Circuit Breaker (MCB) specifically designed for DC (Direct Current) applications. It is a high-current capacity component within Eaton’s xPole series (which includes PL9 and PL10 ranges), engineered to provide essential overcurrent and short-circuit protection for electrical circuits operating on DC voltage. The “C50” in the model code indicates a C-curve tripping characteristic and a rated current of 50 Amperes (A). The “/2” signifies that it is a 2-pole breaker, meaning it can effectively interrupt current on two separate lines, typically the positive and negative conductors in a DC system, or two strings.
Unlike standard AC circuit breakers, DC MCBs like the PL9-C50/2-DC are critically designed to manage the unique challenges of interrupting direct current. DC current lacks a natural zero-crossing point, making the extinguishment of the electrical arc significantly more complex and difficult. Eaton’s PL9-C50/2-DC incorporates specialized arc extinguishing chambers and mechanisms to reliably and safely break high DC fault currents, preventing damage to downstream equipment, mitigating fire risks, and ensuring the safety of personnel. It is primarily used in high-power photovoltaic (solar) systems, large-scale battery energy storage systems, industrial DC power distribution, and other heavy-duty DC applications where robust and reliable protection is required. Its modular design allows for straightforward installation on DIN rails in dedicated DC distribution boards.
Technical Specifications
| Parameter Name | Parameter Value |
|---|---|
| Product Model | PL9-C50/2-DC |
| Manufacturer | EATON (Moeller series xPole) |
| Product Type | Miniature Circuit Breaker (MCB) for DC applications |
| Number of Poles | 2 (two-pole) |
| Rated Current (In) | 50 A |
| Tripping Characteristic | C-curve (magnetic trip from 5 to 10 times In) |
| Rated Operational Voltage (Ue) | Up to 250 V DC per pole (often up to 500 V DC for 2-pole series connection) |
| Rated Insulation Voltage (Ui) | 440 V |
| Rated Impulse Withstand Voltage (Uimp) | 4 kV |
| Rated Short-Circuit Breaking Capacity (Icn) | 10 kA (according to IEC/EN 60947-2) |
| Current Limiting Class | 3 |
| Frequency | 0 Hz (DC application) |
| Operating Temperature | -25°C to +75°C (with derating above 25°C) |
| Mounting | DIN Rail |
| Degree of Protection | IP20 (terminals), higher for enclosure |
| Width in Modular Spacings | 2 |
| Connectable Conductor Cross-Section | 1 to 25 mm² (solid or multi-wired) |
| Special Features | Contact position indicator (red-green), dual function terminals, easy removal from busbar. |
Main Features and Advantages
The EATON PL9-C50/2-DC Miniature Circuit Breaker provides substantial features and advantages, making it an ideal choice for high-current DC circuit protection, where safety and reliability are paramount.
Robust DC Arc Interruption Capability: The most critical feature of the EATON PL9-C50/2-DC is its advanced design for safely interrupting high DC fault currents. Unlike AC, DC arcs do not naturally extinguish. This MCB incorporates sophisticated internal arc chutes and magnetic blow-out systems that rapidly dissipate the arc energy, ensuring safe and reliable tripping even under severe short-circuit conditions. This specialized capability is crucial for protecting expensive DC equipment and preventing fire hazards.
High Current Rating (50 A): With a rated current of 50 Amperes, the PL9-C50/2-DC is suitable for protecting high-power DC circuits. This capacity makes it ideal for main distribution lines from battery banks, large solar PV arrays, or robust industrial DC power supplies.
C-Curve Tripping Characteristic: The “C” characteristic provides thermal overload protection for sustained overcurrents and a magnetic trip at 5 to 10 times its rated current (250A to 500A). This balance makes it suitable for general high-current DC applications that may experience moderate inrush currents upon energization, such as inverters, large DC motor starters, or complex electronic loads.
2-Pole Comprehensive Protection: As a 2-pole breaker, the EATON PL9-C50/2-DC simultaneously breaks both active conductors (positive and negative) in a DC circuit during a fault. This provides complete electrical isolation of the faulty segment, significantly enhancing safety for personnel and ensuring effective system protection.
High Short-Circuit Breaking Capacity (10 kA): A rated short-circuit breaking capacity of 10 kA (according to IEC/EN 60947-2) signifies that the PL9-C50/2-DC can safely interrupt very large fault currents, which is essential for protecting the entire electrical installation from damage in the event of a severe short circuit.
User-Friendly and Durable Design:
- Contact Position Indicator: A clear red-green indicator visually communicates the breaker’s internal contact status (ON/OFF/Tripped), aiding in quick diagnostics and operational safety.
- Dual Function Terminals: Terminals allow for flexible wiring from either the top or bottom, simplifying installation and wiring layout in crowded panels.
- DIN Rail Mounting: Standard 35mm DIN rail mounting ensures quick, secure, and standardized installation into industrial and commercial distribution boards.
- Robust Construction: Built to withstand demanding industrial environments, ensuring long-term reliability and performance.
Application Field
The EATON PL9-C50/2-DC Miniature Circuit Breaker is primarily applied in high-current Direct Current (DC) electrical systems where robust overcurrent and short-circuit protection is paramount. Its significant current rating and specialized DC breaking capabilities make it ideal for various heavy-duty applications.
Large-Scale Photovoltaic (PV) Systems: The EATON PL9-C50/2-DC is extensively used in utility-scale solar farms and large commercial PV installations. It provides protection for the main DC circuits from large solar arrays to inverters, or for high-current strings within combiner boxes, safeguarding against overcurrents and short circuits.
Battery Energy Storage Systems (BESS): In large industrial and commercial battery storage solutions, the PL9-C50/2-DC protects the main DC lines connecting substantial battery banks to inverters or DC loads. This is crucial for the safe operation of battery systems that can supply high fault currents.
Industrial DC Power Distribution: Many heavy industrial facilities utilize large DC power supplies for various applications, including motive power for large machinery, industrial control systems, and specialized processes. The EATON PL9-C50/2-DC provides reliable protection for these main DC distribution feeders.
Data Centers and Telecommunications: While many systems are AC, large data centers and telecom facilities often have significant DC power infrastructures. The PL9-C50/2-DC can protect major DC distribution panels, rectifiers, and high-power server racks, ensuring the continuity and safety of critical operations.
Electric Vehicle (EV) Charging Infrastructure: For high-power DC fast-charging stations, MCBs like the PL9-C50/2-DC are essential for protecting the heavy-duty DC lines supplying power to electric vehicles.
UPS (Uninterruptible Power Supply) Systems: In UPS systems utilizing large battery banks, the PL9-C50/2-DC can protect the DC links between batteries and the UPS inverter, safeguarding against faults.
