EXCB1-DC2-2 PV Combiner Box 2 In 2 Out

EXCB1-DC2-2 2 In 2 Out PV Combiner Box – Independent Protection for Dual MPPT Systems

Manufactured by HUYU Electric, the EXCB1-DC2-2 is a dual-output photovoltaic combiner box designed specifically for dual MPPT systems. This innovative product maintains independent current paths for each MPPT channel. It incorporates a Type 2 surge protective device (SPD) with 40kA Imax, offering reliable protection against surge voltages. Additionally, it features a 32A rated DC MCB and optional fuses for each output circuit, ensuring comprehensive overcurrent and short circuit protection within a robust, shared enclosure. This enables greater flexibility and safety for dual MPPT setups.

Designed for simplicity and convenience, this combiner box streamlines installation for both residential and commercial photovoltaic systems that utilize split arrays, east-west configurations, or multi-zoned layouts. Encased in a durable IP65/IK10 PC/ABS enclosure, the EXCB1-DC2-2 is suitable for outdoor installations and meets international safety standards such as CE, TUV, and CB certifications. HUYU Electric also facilitates factory-direct OEM/ODM services, offering private labeling options and full documentation for solar distributors and installers.

Technical Specifications – EXCB1/3-DC 2-2

The EXCB1-DC2-2 is part of the EXCB family, which includes models with 2, 4, and 6 inputs. It uniquely offers two separate DC output channels, with each channel equipped with its own DC MCB (or isolator in the EXCB3 variant) and additional fuse protection. The integrated SPD safeguards both circuits from surge voltages. Ideal for dual-MPPT inverters, such a configuration isolates and protects two DC circuits within a compact enclosure.

Designed for Dual MPPT and Multi-Zone PV Installations

Dual MPPT inverters are frequently used in modern residential and commercial setups, offering independent optimization for different PV arrays, such as those installed on varied roof orientations. Using a typical 2 in 1 out combiner box would negate the efficiency of dual MPPT tracking by forcing the strings to operate at the same voltage. The EXCB1-DC2-2 keeps the strings electrically independent, ensuring optimized performance for both. With a design that allows pre-wired connections, installers can simply connect input and output cables to the inverter without requiring internal wiring modifications.

OEM/ODM Supply – Dual Output Combiner Boxes for Advanced PV Systems

Buyer’s Guide

How to Select a Combiner Box for Dual MPPT Inverters

Key criteria for choosing the EXCB1-DC2-2 2 in 2 out combiner box in residential and commercial PV systems.

1. Why a 2 In 2 Out Configuration?

Choose a 2 in 2 out PV combiner box when your inverter has dual MPPT inputs and you have two separate PV strings (or string groups) that must remain electrically independent. A standard combiner would force these strings to operate at the same voltage, negating the efficiency of dual MPPT. The EXCB1-DC2-2 provides separate protection and isolation for each string in one consolidated unit, simplifying system design and installation.

2. Protection Coordination per Channel

Each output channel features a 32A DC MCB and optional fuse. Proper fuse sizing ensures alignment with safety standards. Independent breakers allow single-string isolation for maintenance while keeping other strings operational, ensuring sustained energy production.

3. Shared Surge Protection

The integrated Type 2 SPD (40kA Imax) safeguards both channels from voltage surges, eliminating the need for additional SPDs for each input, thus optimizing space and system cost.

4. Enclosure and Outdoor Installation

Built from IP65 IK10 PC/ABS material, this enclosure is UV-resistant and capable of withstanding outdoor conditions. Install vertically with glands facing downward to prevent water ingress. Its -20°C to +60°C operating temperature range ensures reliability across diverse climates.

Frequently Asked Questions

What does a PV combiner box do?

A PV combiner box consolidates the DC output of multiple solar panel strings into one or more protected outputs that feed the inverter. It houses overcurrent protection (DC circuit breakers or fuses), surge protection (DC SPD), and a manual isolation point. A specialized model like the EXCB1-DC2-2 2 in 2 out PV combiner box provides two independent outputs, preserving the separate MPPT channels of dual-input inverters while protecting and isolating both strings within a single enclosure.

What is the 33% rule in solar panels?

The “33% rule” is a practical guideline for enclosure design, suggesting that internal components should not fill more than one-third of the enclosure volume. This leaves adequate space for air circulation and heat dissipation. The EXCB1-DC2-2 combiner box enclosure is designed with this principle, ensuring that the dual MCBs, SPD, fuse holders, and wiring have sufficient air volume for thermal management during continuous operation at rated current.

Why are people getting rid of their solar panels?

Homeowners may remove solar panels due to roof repairs, system underperformance, or changes in financial incentives. Technical reasons for premature removal often relate to DC system failures — water ingress into poorly sealed combiner boxes, surge damage to inverter inputs, or DC arc faults from loose connections. Using a quality, IP65-rated 2 in 2 out combiner box like the EXCB1-DC2-2 addresses these risks: the weatherproof enclosure prevents water damage, the integrated SPD protects the inverter, and the factory-torqued connections minimize the risk of arc faults developing over time.

How to connect 2x solar panels together?

Two solar panels can be connected in series (positive of panel 1 to negative of panel 2) to increase voltage, or in parallel (positive to positive, negative to negative) to increase current. When connecting two separate strings (or single panels used as separate strings) to a dual MPPT inverter, each string should run into its own input on a 2 in 2 out PV combiner box. The EXCB1-DC2-2 accepts two DC inputs, each with its own fuse and DC MCB, and provides two independent DC outputs to the inverter’s MPPT channels. Always ensure the combined voltage and current of each string are within the combiner box and inverter ratings, and use proper MC4 connectors at the panel end.