250A protective box for Delong battery
250A protective box for Delong battery
250A protective box for Delong battery
250A protective box for Delong battery

250A DC Dual-Pole Protection Box for Two Delong / Leapton Lithium Batteries

By Julien Mawet · Solar PV Expert at Wattuneed • Updated April 2026
€458.61
Tax included
Coffret-protection-250A-Delong-Leapton
0768563823817

The 250A bipolar DC protection box is the central safety component for your energy storage systems. Designed specifically for Delong and Leapton batteries, this unit ensures complete isolation by simultaneously disconnecting the positive (+) and negative (-) terminals.

The major advantage of this bipolar protection lies in its ability to completely isolate the circuit: unlike conventional protection, it ensures that no residual current flows during shutdown, thereby protecting the user and the inverter from electric arcs and insulation faults. This device is essential for preserving the lifespan of your lithium cells against overcharging.

Equipped with a robust 250A circuit breaker, it withstands current spikes without overheating. Its omnipolar manual cut-off allows you to work on the installation with complete peace of mind.

Technical features:

  • Bipolar safety: Simultaneous disconnection of the (+) and (-) terminals for true galvanic isolation.
  • 250A rating: Ideal for high-power discharges in lithium battery banks.
  • Full protection: Thermal and magnetic trip on both poles.
  • Robust design: IP65-rated waterproof housing suitable for demanding environments.
  • Ready to use: Internal terminal blocks for large-gauge cables (up to 95mm²).

250A Dual-Pole DC Protection Box for Delong and Leapton Batteries – Ready to Install


The 250A protection box for Delong and Leapton batteriesis a turnkey solution for securing your energy storage systems. This box provides comprehensive bipolar protection, simultaneously isolating the positive and negative terminals to ensure maximum safety against overloads and short circuits.





Contents of the box

This box is supplied complete, pre-wired and ready to install:

  • IP65 enclosure: Robust housing offering total protection against dust and water splashes.
  • 2P 250A DC1000V bipolar circuit breaker (TOMZN - TOM7Z): The central safety device enabling the simultaneous disconnection of both polarities.
  • 2 x 1 m 95 mm² cables with terminals: Secure and optimised connection to the inverter. 
  • 4 x 1.50 m 50 mm² cables with terminals: High-performance connection for linking your Delong or Leapton battery packs to the enclosure.





How the cabinet works

The cabinet is designed to reliably centralise and protect the DC current:

  • The Delong or Leapton batteries are connected to the cabinet via the 4 x 50 mm² cables.
  • Bipolar protection: The 250A 2P circuit breaker acts on both lines (+ and -), ensuring that no residual current flows in the event of a cut-out.
  • The two 95 mm² cables then distribute the power stably to the inverter.

Safety principle: By disconnecting both poles simultaneously, this bipolar box provides true galvanic isolation, protecting the user and the inverter’s electronics from any insulation faults.





Typical applications

  • Residential or commercial installations equipped with Delong and Leapton lithium batteries.
  • Modular storage systems connected in parallel requiring safe isolation.
  • Essential bipolar protection for hybrid PV installations and off-grid sites.





Compatible hybrid inverters 

  • WKS Evo Circle PRO 6.5 kW and WKS MAX II 10 kW
  • Deye 3 kW to 12 kW





Advantages of the enclosure

  • Bipolar safety: Simultaneous disconnection of the (+) and (-) terminals for enhanced protection.
  • Turnkey solution: Enclosure, high-gauge cabling and circuit breaker included.
  • Quick installation: Internal terminal blocks and cables pre-fitted with terminals.
  • DC compliance: Equipment specifically calibrated for high-intensity direct currents (250A).
  • Safe maintenance: Allows the battery bank to be completely isolated during maintenance work.





Commissioning

  1. Check that the double-pole circuit breaker is in the OFF position.
  2. Connect the 95 mm² cables to the battery terminals.
  3. Connect the 50 mm² cables to the DC inputs of the inverter.
  4. It isessential to observe the correct polarity (+ red, - black) on both poles of the circuit breaker.
  5. Switch the circuit breaker to the ON position to energise the system.





Safety and maintenance

  • 250A 2-pole circuit breaker: Resettable magnetic and thermal protection on both poles.
  • Optimised cabling: 95 mm² and 50 mm² cross-sections to minimise voltage drops and overheating.
  • IP65 rating: Suitable for technical environments (battery rooms, garages).
  • Maintenance: Periodic check of terminal tightness and testing of the circuit breaker’s trip button.





FAQ - 250A Dual-Pole DC Protection Box

1. Why is a bipolar cut-off crucial for my Delong or Leapton batteries? +
Bipolar protection (via the RCD) simultaneously isolates the positive (+) and negative (-) terminals. This ensures true galvanic isolation, preventing any residual current from flowing in the event of a trip. This is an essential safety feature to protect the inverter’s electronics and the user against any insulation faults.
2. Which hybrid inverter models is this kit compatible with? +
This enclosure is specifically designed to work with the WKS Evo Circle PRO (6.5 kW) and WKS MAX II (10 kW) inverters, as well as the entire Deye range from 3 kW to 12 kW. It provides a robust protective interface between these devices and your battery bank.
3. What exactly does the "ready-to-install" solution contain? +
The box is supplied complete for immediate commissioning: a robust IP65 enclosure, a 2P 250A circuit breaker, 2 x 95 mm² cables (1 m) for the inverter connection and 4 x 50 mm² cables (1.50 m) to connect your batteries. All cables are pre-fitted with terminals.
4. Why use 95 mm² and 50 mm² cable cross-sections? +
These large cross-sections are essential for handling high currents (250A). They minimise voltage drops and limit conductor heating, thereby ensuring optimal performance and enhanced thermal safety for your storage system.
5. Can I install this box in a garage or a utility room? +
Absolutely. Thanks to its IP65 protection rating, this cabinet is fully protected against dust and water splashes. It is perfectly suited to technical environments such as garages, battery shelters or dedicated rooms.
6. What maintenance does the box require? +
To maintain maximum safety, we recommend periodically checking that the terminals are tight to prevent any poor electrical contact. It is also advisable to regularly use the TOMZN circuit breaker’s release button to test that it is working properly.
Coffret-protection-250A-Delong-Leapton

Data sheet

Type of electrical equipment
Protection box

Specific References

UPC
768563823817
EAN13
0768563823817
MPN
Coffret-protection-250A-Delong-Leapton

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