Junction box quotes depend on the housing, diodes, and potting compound (Source: Made-in-China): Golden Rule: Price is determined by material and dimensions (Source: Made-in-China); Core Component: Bypass diodes (Source: Alibaba); Note: Price premium for TUV certification (Source: bole).
I.
Housing Costs
Material: ABS housing (Source: bole); Fire Safety: Fire-resistant, anti-aging, and insulating (Source: ENF); Waterproofing: IP65 waterproof box (Source: Alibaba); IP67: IP67 rating (Source: Newsun); Dimensions: Customizable sizes (Source: Newsun)—Housing: ABS + Fire resistance + Waterproofing (Three key points).
II.
Diodes
Bypass: Bypass diodes (Source: Alibaba); Quantity: 3 diodes, 4 terminals (Source: bole); Function: Hot-spot protection (Source: Industry standard); Reverse Current: Anti-reverse current (Source: Industry standard); Specifications: 10mm thickness for high-current applications (Source: Accio)—Diodes: Bypass + Quantity + Hot-spot protection (Three key points).
III. Potting Costs
Full Potting: Waterproofing via full potting (Source: 1688); Potting Box: Potting-type junction box (Source: 1688); Waterproofing: Specialized for 250W–300W (Source: 1688); Protection: Sealed component protection (Source: Industry practice); Cost: Potting process fee (Source: Industry practice)—Potting: Full potting + Sealing + Process (three components).
IV.
Cable Connectors
MC4: MC4 connector set (Source: Alibaba); Cable: DC PV cable (Source: Made-in-China); Terminals: Copper terminal soldering (Source: Leader); Male/Female: Male-female mating (Source: Leader); 1500V: 1500V voltage rating (Source: Leader)—Connection: MC4 + Cable + Terminals (three cost items).
V.
Certification Costs
TUV: TUV certification (1000V DC) (Source: Alibaba); UL: UL certification (Source: bole); IP Rating: Ingress protection rating test (Source: bole); System: Quality system cost allocation (Source: Industry practice); Premium: Certified product premium (Source: Industry practice)—Certification: TUV + UL + IP (three requirements).
VI. Price Range
Module-level: $2.45–$2.52/unit (Source: Made-in-China); Crystalline Silicon: $3–$5/unit (potted) (Source: Bole); BIPV: $8.5/unit (Source: Newsun); Domestic: ¥12.5–¥29.2 (Source: 1688); Combiner Box: $100–$550/unit (Source: Made-in-China)—Price: $2.45 + $8.5 + Combiner Box (three tiers).
VII.
Procurement Recommendations
First, inspect the housing (ABS/PPO); second, verify the diodes (number of bypass diodes); third, check the potting (fully potted for waterproofing); fourth, check certifications (TUV/UL);
fifth, compare bulk options (direct purchase from OEM factories)—Junction Box: Housing + Diodes + Certification (three core elements).
