A:Connection and protection.

① Electrical connection: The PV junction box collects power generated by the module through busbars, connects PV modules, and transmits power stably to the inverter. Like connectors, the lower the resistance of the conductive materials inside the junction box, the lower the power loss.

② Hot-spot protection: Equipped with bypass diodes, the junction box diverts current through the conducting diode when module strings are shaded, preventing PV modules from overheating and burning out.

A: It mainly consists of three core components: insulating housing, bypass diodes, and copper conductors.

① Insulating material: Made of weather-resistant, impact-resistant and flame-retardant materials such as PPE and PPO, protecting internal components from environmental damage.

② Bypass diode: The core protective component against PV module damage caused by hot-spot effects. Compared with ordinary silicon diodes, Schottky diodes feature better heat dissipation and lower failure rate.

③ Copper conductor (tinned copper sheet): Designed with low resistance to ensure efficient current output and reduce power loss.

A: PV junction boxes are used in all PV systems, including distributed rooftop power stations, large-scale ground power stations, building-integrated photovoltaics (BIPV), etc. They are essential for both residential and commercial & industrial PV systems.

Key differences lie in protection ratings and parameter matching. For example, offshore PV requires highly sealed, salt-spray resistant junction boxes; 210mm N-type bifacial modules need junction boxes with rated current ≥27A to match high power output and avoid malfunctions.

A: Focus on five critical parameters to avoid risks.

① Rated current / voltage: Must match PV module power. Mainstream modules are compatible with 20A–35A rated current and 1000V–1500V system voltage. Insufficient parameters may cause overheating and burnout.

② Electrical connection points: Most junction box failures result from poor connections. Reducing connection points lowers failure risks and improves system safety.

③ Material quality: Housing preferred PPE/PPO; diodes preferred Schottky type.

④ Ingress protection (IP rating): At least IP67 for outdoor use; IP68 recommended for harsh environments such as coastal, rainy or desert areas.

⑤ Certifications: Must comply with IEC 62790, UL 1703, CQC and other international and domestic certifications. Uncertified products pose serious safety hazards.

A: The controller (control box) communicates with shutdown devices via HPLC, and connects to the cloud platform through the Internet (WiFi / 4G). Users can view real-time data including voltage, current, temperature, power and energy generation on computers and mobile phones.

Shutdown modes include active and passive one-key shutdown, local and remote shutdown, supporting automatic protection during anomalies and manual shutdown as required.

A: The gap lies in four aspects that directly affect system safety and service life.

① Material: High-quality boxes use PPE/PPO engineering plastics with high strength and flame resistance; low-quality products use ordinary PP, which is thin, brittle and heat-intolerant.

② Craftsmanship: High-quality boxes feature firm soldering, reliable sealing and full potting; low-quality ones often suffer from cold solder joints and seal failure.

③ Core components: High-quality boxes use branded Schottky diodes with low failure rates; low-quality ones use ordinary diodes prone to breakdown and overheating.

④ Service life: High-quality boxes support a 25-year module lifespan; low-quality ones may burn or leak within 1–3 years, increasing operation and maintenance costs and fire risks.

A: Three most common failures:

① Burning: Deformation, scorching or odor. Causes include lightning strikes, hot-spot induced thermal breakdown, poor electrical connections, and short circuits due to water ingress.

② Poor contact: Abnormal output and power loss. Causes include loose or corroded terminals, weak soldering, and water leakage due to seal aging.

③ Cold solder joints: Common in full-black modules. Black coatings reduce welding heat, leading to higher contact resistance, overheating, burnout and fire hazards.

A: Water ingress is a critical hazard and requires immediate treatment.

① Mild water ingress (no short circuit or burnout): Disconnect power, dry interior, replace aged sealant and gaskets, reseal securely, and restore use only after insulation resistance tests pass.

② Severe water ingress (short circuit or component damage): Replace with a new junction box, preferably IP68-rated to prevent recurrence.

③ Prevention: Ensure tight sealing during installation, inspect after rain, and use protective sleeves in coastal or high-rainfall areas.

A: The warranty period is usually 5–10 years. High-quality junction boxes can match the 25-year lifespan of PV modules.

Warranty covers housing cracking, seal failure, natural diode damage, and poor conductor contact (excluding man-made damage).

Damage caused by improper installation, impact, unauthorized disassembly, or natural disasters is not covered. A reliable brand with complete warranty is highly recommended.

A: Although small, junction boxes directly affect system safety and revenue. Branded products offer clear advantages.

① Reliable quality: Manufactured in strict accordance with IEC, UL, CQC standards, with low failure rates and long service life.

② Complete after-sales service: Professional support, timely response, free repair or replacement within warranty, reducing O&M costs.

③ Strong compliance: Certified products meet project approval, insurance and export requirements, avoiding acceptance failures.

④ Technical support: Professional guidance on selection, installation and O&M helps avoid risks. Industry data shows nearly 17% of module failures result from improper selection. Choosing a trusted brand protects investment returns.