A PV Distribution Box is an integrated electrical enclosure used in power systems to distribute electrical energy, monitor electrical equipment, and control power lines. It typically consists of components like the cabinet body, circuit breakers, automatic recovery overvoltage and undervoltage protectors, surge protectors, backup circuit breakers for surge protectors, and isolating switches.

Components:

1.Cabinet Material:

Stainless Steel Cabinet: Rust and corrosion-resistant, waterproof, dustproof, durable, and easy to install.

Galvanized Steel Cabinet: Rust and corrosion-resistant, aesthetically pleasing, and cost-effective.

2.Circuit Breakers:

Function: To cut off the circuit in the event of a short circuit or overload.

Types: Single-phase 220V and three-phase 400V.

Common Specifications: 16A, 25A, 32A, 40A, 50A, 63A, etc.

3.Residual Current Operated Circuit Breakers (RCCB):

Function: To provide leakage protection by detecting abnormal currents.

4.Automatic Recovery Overvoltage and Undervoltage Protectors:

Function: Automatically cut off the power when the line voltage exceeds the protection range (indicator light turns red), and automatically reconnect when the voltage returns to normal.

5.Surge Protectors (SPDs): 

Also known as lightning arresters, these devices protect electronic equipment, instruments, and communication lines from spikes in voltage or current caused by external interference.

Working Principle: They divert excessive current or voltage to the ground in a very short time to prevent damage to other equipment in the circuit.

6.Disconnect Switches and Knife Switches:

Ensure reliable isolation of the inverter from the grid during faults or maintenance in photovoltaic systems.

Types of PV Distribution Boxs:

1.DC Distribution Cabinets:

Function: Aggregate the DC power from photovoltaic modules and feed it into the inverter or directly supply other DC loads (such as batteries and charging power supplies).

Features: Can be equipped with intelligent monitoring units to detect voltage and current for all aggregation circuits, facilitating system management.

2.AC Distribution Cabinets:

Function: Ensure the switching function of backup inverters, guarantee the normal power supply of the photovoltaic system, and measure the electrical energy of the circuits.

Features: Equipped with lightning protection, power generation, and consumption measurement devices, and configured with intelligent electric meters that communicate with the monitoring system via RS485.

Installation Methods:

1.Wall-Mounted:

The distribution cabinet is fixed to the wall. This method requires consideration of the wall's load-bearing capacity and whether the wall material and structure are suitable for installation. Typically used for household photovoltaics or smaller-scale photovoltaic plants.

2.Bracket-Mounted:

The distribution cabinet is installed on a bracket, making wiring and maintenance convenient. Commonly used in larger-scale photovoltaic plants.

3.Ground-Mounted:

The distribution cabinet is placed on the ground, requiring consideration of foundational construction. Suitable for larger-scale power plants.

Ventilation and Safety:

· Proper ventilation is necessary to prevent equipment overheating. During installation, ensure there is enough space and sufficient ventilation openings around the distribution cabinet.

· Both wall-mounted and bracket-mounted installations must be secure to prevent movement. Ensure the bracket's material and structure can support the distribution cabinet's weight and withstand external environmental influences.

· Each cable and device must be labeled clearly, with detailed instructions marked on the distribution cabinet to facilitate future maintenance and operation, avoiding misoperation due to unclear labels.