I. Standards
What do the standards specify?
Regarding the standard’s details: GB/T 5585.1 — National Standard Information Public Service Platform (Copper, aluminum, and their alloy busbars for electrical purposes – Part 1: Copper and copper alloy busbars GB/T 5585.1-2018; ICS 29.060.10; CCS K11; Technical Committee: National Technical Committee on Bare Wires); 2018 — China Standards Online Service (GB/T 5585.1-2018 Copper, aluminum, and their alloy busbars for electrical purposes – Part 1: Copper and copper alloy busbars [Current]; Issue Date: 2018-12-28; Implementation Date: 2019-07-01; Specifies designations, product representation, technical requirements, testing, and delivery lengths for copper and copper alloy busbars for electrical purposes); Withdrawn — National Standard Information Public Service Platform (GB/T 5585.1-2005; Issue Date: 2005-08-26; Implementation Date: 2006-04-01; Withdrawal Date: 2019-07-01); Consolidated — National Standard Information Public Service Platform (Consolidated “Copper, aluminum, and their alloy busbars for electrical purposes” – Part 1: General requirements, Part 2: Copper busbars, Part 3: Aluminum busbars; Replaces GB 5585.1-1985, GB 5585.2-1985, and GB 5585.3-1985 in their entirety); Flat wire — National Standard Information Public Service Platform (Copper, aluminum, and their alloy flat wires for electrical purposes – Part 1: General requirements GB/T)
5584.1-2020 (Issue date: 2020-12-14; Implementation date: 2021-07-01; Status: Current; Source: National Standard Information Public Service Platform); 5585-2005 — Chongqing Ge Pai (Standard for copper, aluminum, and their alloy busbars: GB/T 5585-2005; copper busbar cross-sectional dimension range: 2.24 mm ≤ a ≤ 50.00 mm, 16.00 mm ≤ b ≤ 400.00 mm; Chongqing Ge Pai) — Key standard references: GB/T 5585.1-2018 (superseding/consolidating 5585-2005 regarding flat wire); compliance with the relevant standards is essential.
II.
Conductivity
What to look for regarding conductivity.
Regarding conductivity in practice, the figures are viewed as follows: 100% — GB/T 5585.1 (resistivity of copper and copper alloy busbars at 20°C must comply with Table 11; for temper R, DC resistivity at 20°C ≤ 0.017241, conductivity ≥ 100% IACS); 97% — GB/T 5585.1 (for temper Y, DC resistivity at 20°C ≤ 0.01777, conductivity ≥ 97% IACS); 98% — Docin.com (the 2025 revision of GB/T 5585.1 “General Technical Specifications for Copper Busbars for Electrical Purposes,” issued jointly by SAMR and SAC, raises the minimum conductivity from 97% IACS to 98% IACS); 100% — rvmetco (Material Grades ETP Copper C11000; electrical conductivity ≥ 100% IACS for ETP, ≥ 97% IACS for DHP); 97% — Luoyang Jingshun (standard conductivity at 20°C ≥ 97% IACS per the International Annealed Copper Standard; batches can reach 98% IACS; resistivity as low as 0.01724 Ω·mm²/m; T2 oxygen-free copper busbars offer peak electrical performance, second only to silver); 101% — Oriental Copper (high-conductivity electrolytic tough pitch OC-ETP and high-conductivity oxygen-free OF copper; electrical conductivity of approximately 101% IACS). In summary, the six conductivity benchmarks are: 100%, 97%, 98%, 100%, 97%, and 101%.
III. Grade Designation
What to look for in the grade designation.
Regarding grade designations, here is how they are interpreted: T2—Made-in-China.com (Common material is T2 pure copper; standard GB/T5585.1-2005; copper busbars are high-current conductive products suitable for electrical engineering applications such as high/low-voltage switch contacts, power distribution equipment, and busbar trunking systems; features include low resistivity and high bendability); TMR—Antpedia (Table 10: Copper and copper alloy busbar resistivity; models TMR/THMR: 20°C DC resistivity ≤0.017241, conductivity ≥100% IACS; models TMY/THMY: ≤0.01777, ≥97%); TMY—Jintian Copper (TM pure copper busbar performance advantages: high copper content, low oxygen content, dense and uniform microstructure; TMY specs: 2.24–50.00 mm thickness, 16.00–400.00 mm width; resistivity ≤0.01777; Brinell hardness HB ≥65; oxygen content ≤0.002; standard GB/T5585.1-2018); T2 Coiled Busbar—Tuomeiwei (T2 coiled busbar: 2.5–6 mm thickness, 50–120 mm width; conductivity ≥97% IACS; Brinell hardness HB ≥65; oxygen content ≤0.002; GB/T 5585.1-2018); 99.90%—pufamaterials (Conductivity ≥98% IACS [Soft]; Standards: ASTM B187, GB/T 5585.1, IEC 60439; Applications: Switchgear, Transformer, Earthing); ETP—DeepDrawTech (T2 Copper ETP or TU1/TU2 OFHC; copper purity directly correlates to electrical conductivity measured in the International…
Annealed Copper (IACS Standard; T2/C11000/ETP; ≥99.90% purity; ≥100% IACS; DeepDrawTech) — Six key grade indicators: T2, TMR, TMY, T2 coil/strip, 99.90%, and ETP; ensure all six are verified.
IV.
Testing
What to look for during testing.
Based on testing practices, the inspection covers the following six aspects: Eddy current (method per GB/T 32791-2016; instrument range: 4%–103% IACS); Accuracy (measurement accuracy: ±1% IACS); Standard reference blocks (two blocks required: one high-value block at ~100% IACS and one low-value block at ~5% IACS); Conductivity (standards GB/T 5585.1-2018 and GB/T 5584.1-2020; T2 copper busbar specifications: Cu content ≥99.9%, conductivity ≥56 MS/m, resistivity ≤0.0178 × 10⁻⁶ Ω·m; material certificate and inspection report required); Dimensions (cross-sectional range: 2.24 mm ≤ a ≤ 50.00 mm; 16.00 mm ≤ b ≤ 400.00 mm); and Oxide film (surface oxide film thickness ≤50 nm; grain orientation uniformity via EBSD with a coefficient of variation ≤0.15; residual stress ≤3). Thorough inspection across these six areas is essential.
V.
Selection
What to look for when selecting.
When making a selection, consider these six factors: Photovoltaic Inverters—Made-in-China (High-Performance Custom Copper Bus Bar for Solar Inverters; electrical conductivity at 75°C ≥46 m/(Ω·mm²); copper content 99.90%; compliant with GB/T 5585.1); Tin Plating—pufamaterials (Surface: Bare/Tin Plated 3–12 μm; Edge: Square/Radius/Deburred); Conductivity—G and N Fortune (ETP copper typically achieves conductivity of approximately 100% IACS—International Annealed Copper Standard—making it ideal for electrical applications); Elongation—Made-in-China (Elongation ≥14%–17.80%); Coiled Busbars—Jintian Copper (Grades T2, TMR, TMY; Tensile strength: soft state R ≥206; Hardness: hard state Y ≥65; Resistivity: ≤0.01777 Ω·mm²/m; Conductivity: 97% IACS; Supply length: flexible/by weight); Purity—ACL Cables (Copper content: 99.90% min; Max electrical resistivity: 0.01759 µΩ·m; Conductivity IACS @ 20°C: 98% min). By carefully evaluating these six criteria—PV inverters, tin plating, conductivity, elongation, coiled busbars, and purity—you can make an informed choice.
Conclusion
What is the conductivity standard for photovoltaic copper busbars?
The conclusion is that evaluating these standards involves five key aspects: specifications, conductivity, material grade, testing, and selection.
Standards—National Standard Information Public Service Platform (GB/T 5585.1-2018 Copper and copper alloy busbars; under the jurisdiction of the National Technical Committee on Bare Wires), China Standards Online Service Network (GB/T 5585.1-2018 current version, effective July 1, 2019), National Standard Information Public Service Platform (GB/T 5585.1-2005, withdrawn July 1, 2019), National Standard Information Public Service Platform (consolidated from the three parts of the 1985 version), National Standard Information Public Service Platform (GB/T 5584.1-2020 Flat wires—General requirements), Chongqing Ge-Pai (GB/T 5585-2005 Copper busbars, 2.24mm ≤ a ≤ 50mm); Conductivity—GB/T 5585.1 (Soft state R: ≤0.017241, conductivity ≥100% IACS), GB/T 5585.1 (Hard state Y: ≤0.01777, conductivity ≥97% IACS), Docin.com (2025 revised edition: minimum conductivity raised to 98% IACS), rvmetco (ETP ≥100% IACS, DHP ≥97% IACS), Luoyang Jingshun (T2 pure copper: ≥97% IACS, batch average 98% IACS, resistivity 0.01724), Oriental Copper (OC-ETP and OF copper conductivity approx. 101% IACS)
Copper; Grades—Made-in-China.com (T2 oxygen-free copper GB/T5585.1-2005 for high-current conductive products), Antpedia (TMR/THMR ≥100% IACS, TMY/THMY ≥97% IACS), Jintian Copper (TMY resistivity ≤0.01777, oxygen content ≤0.002), Tuomeiwei (T2 coil/busbar conductivity ≥97% IACS), pufamaterials (conductivity ≥98% IACS, ASTM B187, IEC 60439), DeepDrawTech (T2 ETP ≥99.90% purity, ≥100% IACS); Testing—cnfa (GB/T 32791-2016 eddy current testing 4%–103% IACS), cnfa (measurement accuracy ±1% IACS), cnfa (high-value standard block 100% IACS, low-value 5% IACS), Daqing Petrochemical (T2 copper content ≥99.9%, conductivity ≥56 MS/m, includes material certificate/inspection report), Chongqing Ge Pai (copper busbar cross-sectional dimension range), Docin.com (surface oxide film thickness ≤50 nm, EBSD coefficient of variation ≤0.15); Selection—Made-in-China (PV inverter copper busbar, 75°C conductivity ≥46 m/(Ω⋅mm²), 99.9% copper content).
