Product Description
The Eaton PL9-C6/2-DC is a Miniature Circuit Breaker (MCB) specifically designed for DC (Direct Current) applications. Part of Eaton’s xPole PL9 series, these MCBs are essential safety devices used to protect electrical installations against overloads and short circuits in DC circuits.
The “PL9” indicates that it belongs to the high-performance PL9 series. The “C6” specifies its tripping characteristic and rated current:
- C characteristic: This means the breaker will trip when the current reaches 5 to 10 times its rated current. This is a common characteristic for general applications and provides protection for cables and conductors against overcurrents and short circuits.
- 6 A: This is the rated current (In), meaning the breaker is designed to carry up to 6 Amperes continuously.
The “/2” indicates that it is a 2-pole breaker, meaning it provides protection for two conductors. Finally, “-DC” explicitly states that it is designed for DC (Direct Current) operation, which is critical as DC fault interruption requires different mechanisms than AC due to the lack of zero crossings.
This MCB is typically used in photovoltaic (solar) systems, battery backup systems, industrial DC control circuits, and other applications where direct current power is utilized and overcurrent protection is required. It is designed for DIN rail mounting, making it easy to integrate into distribution boards and control cabinets.
Product Parameters
The Eaton PL9-C6/2-DC possesses the following key technical specifications:
| Parameter | Specification |
|---|---|
| Product Type | Miniature Circuit Breaker (MCB) |
| Manufacturer | Eaton (Moeller series xPole) |
| Model Series | PL9-DC |
| Rated Current (In) | 6 A |
| Number of Poles | 2-pole |
| Tripping Characteristic | C (Magnetic trip between 5 to 10 x In) |
| Voltage Type | DC (Direct Current) |
| Rated Operational Voltage (Ue) | Up to 220 VDC (for 2-pole, verify specific configuration for max voltage per pole) |
| Rated Insulation Voltage (Ui) | 440 V |
| Rated Impulse Withstand Voltage (Uimp) | 4 kV |
| Rated Short-Circuit Breaking Capacity (Icn) | Typically 10 kA (according to IEC/EN 60947-2 for DC applications) |
| Current Limiting Class | 3 |
| Frequency Rating | 0 Hz (for DC applications) |
| Width | 2 modular spacings (approx. 35 mm) |
| Built-in Depth | Approximately 70.5 mm |
| Degree of Protection | IP20 (Terminals) |
| Ambient Operating Temperature | $-25^\circ$C to $+75^\circ$C |
| Connectable Conductor Cross-Section | 1 to 25 mm² (multi-wired and solid-core) |
| Mounting | DIN rail (EN 60715) |
| Standards Compliance | IEC/EN 60947-2 (for circuit breakers for industrial use) |
| Overvoltage Category | III |
| Pollution Degree | 2 |
| Contact Position Indicator | Red-green indicator for ON/OFF status |
Advantages and Features
The Eaton PL9-C6/2-DC offers several advantages and features:
- Dedicated DC Protection: Specifically designed and tested for DC circuits, ensuring reliable and safe interruption of DC faults, which is more challenging than AC faults due to the absence of natural zero crossings.
- High Breaking Capacity: With a typical 10 kA short-circuit breaking capacity, it can safely interrupt significant fault currents, providing robust protection for downstream equipment and wiring.
- C Tripping Characteristic: Suitable for a wide range of general applications, including resistive and inductive loads, offering good protection against overloads and short circuits.
- 2-Pole Design: Provides simultaneous breaking of two conductors, which is often required for safety and circuit integrity in DC systems.
- Compact DIN Rail Design: Allows for efficient use of space in control cabinets and distribution boards, and facilitates easy installation and removal.
- Reliable Performance: Eaton’s xPole series is known for its quality and durability, ensuring a long operational life and consistent protection.
- Contact Position Indicator: The red-green indicator provides a clear visual indication of the breaker’s contact status (ON/OFF), enhancing safety and ease of troubleshooting.
- Broad Temperature Range: Suitable for operation in various industrial and outdoor (within enclosures) environments.
Application Areas and Application Cases
The Eaton PL9-C6/2-DC is widely used in applications where DC power distribution and circuit protection are required:
- Photovoltaic (Solar) Systems: Protecting DC strings, inverters, and battery charge controllers in residential, commercial, and industrial solar installations.
- Battery Energy Storage Systems (BESS): Providing overcurrent and short-circuit protection for battery banks and associated DC loads or charging circuits.
- Industrial Control Systems: Protecting DC power supplies, control circuits, and automation equipment (PLCs, sensors, actuators) that operate on DC voltage.
- Telecommunication Systems: Safeguarding DC power distribution in communication cabinets and data centers.
- Electric Vehicle (EV) Charging Infrastructure: Protection of DC charging circuits.
- Uninterruptible Power Supplies (UPS): Protecting DC links and battery circuits within UPS systems.
Application Case: In a commercial rooftop solar array, multiple strings of solar panels were connected to a central inverter. To ensure individual string protection and safe disconnection for maintenance, Eaton PL9-C6/2-DC miniature circuit breakers were installed in a DC combiner box for each pair of strings. For example, two strings, each generating current up to 3A, were routed through a single PL9-C6/2-DC breaker. In the event of a fault (e.g., short circuit) within one of the strings, the C6 characteristic ensured that the breaker would trip quickly to isolate the fault, preventing damage to the panels or inverter and ensuring the safety of personnel performing maintenance. The 2-pole design allowed for complete isolation of both positive and negative DC conductors.
Competitive Comparison
The Eaton PL9-C6/2-DC competes with other manufacturers of DC miniature circuit breakers for similar applications. Key competitors include:
- Schneider Electric (Acti9 C60H-DC, C60PV-DC series): Offers a comprehensive range of DC MCBs with various pole configurations and current ratings, often focusing on solar and industrial DC applications.
- ABB (S200M UC series): Provides MCBs for universal current applications (AC/DC), with specific models optimized for DC systems, offering robust protection.
- Siemens (5SY series DC MCBs): Part of their Sentron portfolio, Siemens offers MCBs specifically designed for DC circuits, commonly used in industrial and infrastructure projects.
- Legrand (DRX 6000/DX³ DC series): Offers MCBs for DC applications, including those for photovoltaic systems.
The Eaton PL9-C6/2-DC differentiates itself by:
- Brand Reputation: Eaton is a global leader in power management, and its Moeller series is well-regarded for quality and reliability in electrical distribution components.
- Dedicated DC Design: While some competitors offer universal AC/DC breakers, the PL9-DC series is specifically optimized for DC fault interruption, which requires unique arc-extinguishing capabilities due to the lack of natural zero crossings.
- Standard Compliance: Meets relevant IEC/EN standards for circuit breakers, ensuring product safety and performance.
- Compact and Standardized: Its modular design and DIN rail mounting are standard across the industry, facilitating easy integration into existing or new electrical panels.
While competitors offer similar functionality, Eaton’s PL9-DC series is a strong contender due to its specialized design for DC, proven reliability, and strong brand presence in electrical power distribution.
Selection Advice
When selecting the Eaton PL9-C6/2-DC, consider the following:
- Application Type: Confirm your application is indeed DC-based. Never use an AC-only MCB in a DC circuit, as it will not reliably clear DC faults.
- Rated Current (6A): Ensure the 6A rating is appropriate for the continuous current of your circuit. Select a breaker with a rating slightly higher than your expected maximum continuous load but lower than the wire’s ampacity.
- Number of Poles (2-Pole): Verify that a 2-pole breaker is required for your circuit configuration. Some DC applications might require 1-pole or 4-pole breakers depending on grounding and isolation needs.
- Voltage Rating: Ensure the maximum DC voltage of your system (e.g., system voltage of solar strings) does not exceed the breaker’s rated operational voltage (Ue), which is typically 220 VDC for a 2-pole configuration.
- Tripping Characteristic (C): The C characteristic is suitable for general-purpose circuits. If your application has very high inrush currents (e.g., large motors, transformers), a D characteristic might be more appropriate. If it has sensitive electronic loads, a B characteristic might be considered (though less common in DC).
- Short-Circuit Current: Calculate the maximum prospective short-circuit current at the point of installation and ensure it does not exceed the breaker’s rated short-circuit breaking capacity (10 kA).
- Environmental Conditions: The operating temperature range is wide, but ensure the enclosure provides adequate protection (e.g., IP65 for outdoor use if the MCB is inside a cabinet).
