Automatic Circuit Breaker 125A DC 250V Resettable

Automatic Circuit Breaker 125A DC 250V - Resettable Protection for Solar Batteries

The 125A DC 250V automatic circuit breaker is a miniature circuit breaker specially designed to protect battery systems in photovoltaic installations. Unlike traditional single-use circuit breakers, this resettable device offers permanent protection against overloads and short circuits, with the option of manually resetting after tripping.

Automatic and resettable protection

This automatic circuit breaker combines the advantages of a conventional circuit breaker with the convenience of a resettable system:

• Rated current 125A: Suitable for high-power battery installations
• Voltage 250V DC: Compatible with 12V, 24V, 48V systems and high-voltage configurations up to 250V
• 4kA breaking capacity: Effective protection against severe short circuits
• Manual reclosing: No replacement required after tripping
• 1 pole + neutral: Standard configuration for DC applications

Resettable automatic circuit breaker: Economical and practical. After a trip, simply solve the problem and reset the circuit breaker. No more spare circuit breakers to store and replace!

Applications and compatibility

The 125A DC 250V automatic circuit breaker is particularly recommended for :

• Lithium battery protection: Pylontech, Delong, BYD, Dyness (up to 250V DC)
• Battery-inverter connection: securing the main DC circuit
• Stand-alone systems: motorhomes, barges, isolated sites
• Residential photovoltaic systems: up to 30 kWh storage capacity
• Bi-directional protection: battery charging and discharging

Compatible with all types of solar batteries: lithium LiFePO4, lead-acid, gel, AGM.

Assembly and installation

The circuit breaker is easily mounted on a standard 35mm DIN rail, as in conventional electrical switchboards. Its compact dimensions allow optimum integration into battery protection cabinets.

Typical configuration:

1. Battery terminal (+) → 125A automatic circuit breaker → Inverter/Load
2. Mounting: DIN rail in IP65 enclosure or main switchboard
3. Cable cross-section: 35-50 mm² recommended for 125A
4. Terminals: Optimised clamping for high cross-section copper cables

For a complete guide to installing batteries with circuit breaker protection, see our technical guide to installing solar batteries.

Sizing according to Battery Power

Advantages of Resettable Technology

Comparison between traditional and automatic circuit breakers:

Technical specifications

• IEC/EN 60947-2 compliance: European standard for low-voltage circuit breakers
• GB14048.2 compliance: International standard for electrical equipment
• CE certification: Marketed in the European Union
• ISO9001 certification: Certified quality system
• Optimised tripping curve: Fast magnetic tripping
• Modular mounting: Standard 35mm DIN rail

Maintenance and service life

The automatic circuit breaker is designed for a service life of at least 10,000 mechanical cycles. Maintenance operations are limited to :

• Monthly: Visual check of good condition
• Annual: Tightening of terminals (torque 2.5 Nm)
• Functional test: Manual triggering/resetting once a year
• Replacement: Only if mechanical failure (rare)

Cable sizing and cross-section

To take full advantage of the circuit-breaker's 125A capacity, cable sizing is crucial:

• 25 mm²: Length ≤ 1m, direct current ≤ 100A
• 35 mm²: Length ≤ 2m, continuous current ≤ 125A (recommended)
• 50 mm²: Length > 2m or high peak current
• 70 mm²: High power industrial applications

Use our free cable cross-section calculator to check the sizing of your installation.

Important precautions for use

⚠️ Warning: This circuit-breaker is designed exclusively for direct current (DC). Never use it on an alternating current (AC) circuit, otherwise it could be destroyed and cause a fire.

• Always observe polarity when wiring
• Do not exceed 250V DC between terminals
• Install in a dry environment (IP65 enclosure recommended)
• Operating temperature : -25°C to +60°C
• Do not use as a frequent on/off switch

Calculating compatible power

To determine whether the 125A circuit breaker is suitable for your installation:

Formula: Power (W) = Battery voltage (V) × Current (A)
Example: Battery 48V × 125A = 6,000W (6 kW) continuous

This circuit breaker is therefore ideal for installations with :

• Inverter up to 6 kW at 48V
• Inverter up to 3 kW at 24V
• Batteries with maximum discharge current ≤ 125A

Technical support and documentation

If you have any questions about sizing, installation or choosing the right automatic circuit breaker for your battery configuration, our technical team is available via our online support platform.

Documentation available: detailed technical data sheet, wiring diagrams, battery circuit breaker sizing guide.