DC 500A Busbar distribution box

Busbar 500A DC Distribution Box - Complete solution with 4 circuit breakers 125A

The Busbar 500A DC distribution box is a professional, ready-to-use solution for centralising and securing DC distribution in medium- to high-power photovoltaic installations. Supplied complete with 2 copper bars (positive and negative busbars) and 4 125A DC circuit breakers, this box can be used to connect up to 4 battery circuits or inverters in complete safety.

Box contents - Turnkey solution

The box is supplied fully equipped and ready to install:

• 2 copper busbars: positive busbar + negative busbar for 500A distribution
• 4 DC 125A circuit breakers: Individual protection for each feeder (resettable)
• IP65 enclosure: total protection against dust and water splashes
• Connection terminals: High cross-section for 35-70 mm² cables
• Battery and connection cables included
• Wall mounts: Mounting system included

What is a busbar and how does it work?

A busbar is a copper conductor bar used to distribute electrical current to several circuits in parallel from a central point. This box includes :

• Positive busbar (busbar +): Distributes the current to 4 circuit breakers 125A
• Negative busbar (busbar -): Common return for the 4 circuits
• 4 circuit breakers 125A: Each circuit breaker protects an independent feeder.

Operating principle : The batteries are connected to the busbar input (+ and -). The current is then distributed to 4 circuits individually protected by 125A circuit breakers, supplying inverters or other equipment.

Typical applications and configurations

This enclosure with 4 x 125A circuit breakers can be used in a number of professional configurations:

Sizing and power supported

With 4 circuit breakers of 125A each, the enclosure can handle :

Concrete example: In 48V, you can connect 4 inverters of 6 kVA each (i.e. 24 kVA total) or 4 battery packs with 125A individual protection per pack.

Advantages of integrated 125A DC circuit breakers

The 4 included 125A DC circuit breakers offer several advantages over traditional fuses:

Double busbar system: positive and negative

The enclosure incorporates two separate copper busbars:

• Positive busbar (+): Input connection from pole + batteries → distribution to 4 circuit breakers 125A
• Negative busbar (-): Input connection from pole - batteries → return distribution to 4 circuits

This double busbar configuration guarantees :

• Perfect current balancing on all feeders
• Minimal ohmic losses (high-section copper)
• No single point of failure
• Symmetrical and professional wiring

Commissioning

1. Check that all circuit breakers are in the OFF position
2. Connect all cables (batteries and inverters)
3. Check polarity (+ red, - black)
4. Turn the circuit breakers ON one by one
5. Check that each circuit is working correctly

For a complete guide, see our parallel solar battery installation guide.

Maximum protection and safety

The cabinet offers several levels of protection:

• 4 DC 125A circuit breakers: overload and short-circuit protection per feeder
• 4kA breaking capacity: effective protection against short-circuits
• Manual reset: No danger from automatic reset
• Galvanic isolation: Each circuit electrically isolated
• IP65 enclosure: total protection against dust and water splashes
• Large copper busbar: No overheating up to 500A

Example of a real installation

Configuration of 4 Pylontech US5000 batteries (48V 100Ah) with 2 inverters:

• Cabinet input: 4 batteries in parallel = 48V 400Ah (19.2 kWh) via 70 mm² cables
• Circuit breaker 1: WKS Evo Circle PRO 6.5kVa n°1 UPS (50 mm² cable)
• Circuit breaker 2: Inverter WKS Evo Circle PRO 6.5kVa n°2 (50 mm² cable)
• Circuit breaker 3: DC-DC charger or auxiliary converter (35 mm² cable)
• Circuit breaker 4: Reserve for future expansion

This configuration provides a total power of 10 kVA in parallel with individual protection for each piece of equipment.

Advantages of the Busbar system with circuit breakers

Comparison with traditional installation :

Technical characteristics of the 125A circuit breakers

The 4 built-in 125A DC circuit breakers offer :

• Rated current: 125A DC continuous
• Maximum voltage: 250V DC
• Breaking capacity: 4kA
• Type: manually resettable
• Service life: 10,000 mechanical cycles
• Compliance: IEC/EN 60947-2

For more information on DC circuit breakers, see our 125A automatic circuit breaker product sheet.

Maintenance and servicing

The busbar enclosure with circuit breakers requires minimal maintenance:

• Monthly: Visual check of general condition and circuit breakers
• Quarterly: Manual test of the 4 circuit breakers (tripping/resetting)
• Annually: Tighten all connections (torque 2.5-3 Nm)
• Annually: Check enclosure temperature during operation (thermography if possible)

Why choose this Busbar enclosure?

Professional all-in-one solution :

• Cost savings: 4 x 125A circuit breakers included
• Time saving: simplified installation vs. traditional wiring
• Reliability: Professional components, solid copper busbar
• Safety: Individual protection per circuit, IP65 enclosure
• Scalability: Easy to add/remove circuits
• Compliance: Installation to electrical standards