The Ultimate Guide to Choosing The Right Type of PROJOY’s Electric Boxes

Electric boxes are the core hubs connecting modules, inverters, and loads. The selection directly impacts system safety, efficiency, and the convenience of maintenance. 

Projoy Electric has developed a series of high-quality products, including DC Electric Boxes, AC Electric Boxes, and AC & DC Electric Boxes, providing the market with a full range of PV distribution solutions. 

Among all, how do you choose the most suitable "safety guardian" for your PV system? 

1. Define Requirements & Specifications 

First and foremost, you must define your specific requirements. 

Load Type: Determine if you need a DC Electric Box, an AC Electric Box, or a Combined AC & DC Electric Box.

Rated Current & Voltage: Select the appropriate rated current and voltage level based on the system's maximum load.

Environmental Conditions: Consider the installation location's environmental factors (e.g., temperature, humidity) to choose a Electric Box with the corresponding protection rating (IP rating).

2. Choose the Right Electric Box Type

DC Electric Box: Suitable for distributing and protecting DC power within PV systems. PROJOY's DC Electric Boxes feature efficient overcurrent and short-circuit protection functions and support modular design for easy maintenance and expansion.

AC Electric Box: Essential for scenarios where DC power is converted to AC power for use. It ensures the safety and stability of power transmission while providing necessary electrical isolation and protection measures.

AC & DC Electric Box: Combines the advantages of both DC and AC Electric Boxes. Ideal for complex systems requiring simultaneous handling of DC and AC power. This type is particularly suitable for PV plants integrated with energy storage systems, effectively enhancing overall system efficiency and reliability.

3. Selecting Internal Components

When selecting an Electric Box, it is essential to choose the corresponding internal components based on the actual application scenario and specific functional requirements.

For example:

Electric Boxes for industrial plants need to consider circuit breakers capable of handling high loads, multiple circuits, and strong anti-interference. 

Residential applications prioritize earth leakage protection (RCD/RCBO), overload protection, and ease of use, requiring miniature circuit breakers (MCBs) with integrated earth leakage protection.

In addition to that, environmental conditions (humidity, temperature, IP rating), future expansion needs, and intelligent management requirements must also be considered. Choose smart components with features like remote monitoring, current/voltage monitoring where needed.

Only through precise configuration based on the actual usage scenario can the safety, stability, and efficient operation of the distribution system be ensured.

4.Analysis & Key Selection Points of PROJOY's Electric Boxes

DC Electric Box (PEJB Series) : The Guardian Between Modules & Inverters 

Function: Installed between PV strings and the inverter's DC input, primarily handling DC-side protection.

Selection Guide: Match the model to your specific requirements.

AC Electric Box (PEDB Series): The Final Line of Defense for Inverter Grid Connection

Function: Located between the inverter's AC output and the grid/load, providing AC-side protection and control.

Selection Guide: Match the model to your specific requirements.

AC & DC Electric Box (PEJDB Series): Innovative Design, Simplifying Complexity

Revolutionary Breakthrough: PROJOY pioneered the integrated design, combining both DC and AC distribution functions within a single enclosure.

Selection Guide: Match the model to your specific requirements.

5.Pitfall Avoidance Guide: Common Selection Mistakes

Undersized Fuse Rating: Fuse current rating must be ≥ 1.5 times the string short-circuit current (Isc) to avoid fuse failure.

Ignoring DC Surge Protection (SPD): Over 30% of installers neglect this. Yet it is Essential in high lightning risk areas.

Inadequate Enclosure Protection (IP Rating): Outdoor installations must use IP65 or higher (PROJOY achieves IP65).

Mixing AC & DC Components: Strictly prohibited to use AC switches in DC circuits. Must use PV switches (e.g., PROJOY PEDS Isolator Switches, UL certified).

Ignoring Future Expansion: Reserve 15%-20% capacity during selection.

6. PROJOY Customization Services: Meeting Diverse Needs 

PROJOY understands the uniqueness of each PV plant and the diversity of customer needs. Based on actual customer requirements, we can flexibly configure various components, such as adding smart meter modules (like the PEEM-T02/T03), providing strong support for intelligent plant management.

This flexibility and customization enable PROJOY Electric Boxes to better adapt to PV plants of different scales and types, satisfying diverse customer needs.

With its rich product line, professional technical team, and customized services, PROJOY provides professional and reliable distribution solutions, guiding you safely through your PV system Electric Box selection.