Cable that works outdoors, moves, or hangs between two poles is judged differently from cable that sits still in a tray. A DC array runs at 1500 V and bakes at 90 °C for a quarter of a century. A rubber lead on a mobile machine bends thousands of times a week and gets dragged through oil. A bare conductor carries its own weight plus wind and ice across a 300 m span. A 2.5 mm² wire is pulled through twenty bends of conduit by an electrician who will not forgive a stiff jacket.
Voltcore covers all four families from its 86,000 m² plant in Yixing, Jiangsu, where 32 lines strand, extrude and cross-link to EN, IEC, UL and NFC specifications. The PV line holds TÜV Rheinland type approval for solar cable, the building wire line carries a UL listing, and the rubber and overhead conductor lines run to JB/T 8735, HD 22 and IEC 61089. Shipments leave Shanghai or Ningbo in 15–25 working days. Bare conductor is quoted against the metal index you trade against, not against a fixed list.
A bare overhead conductor is bought on three numbers: DC resistance in Ω/km, breaking load in kN, and kilograms per kilometre. The first is an electrical purchase, the second is a structural one, and the third is what the invoice is calculated on. Utility buyers and EPC contractors tendering for rural electrification or grid reinforcement read those three columns before they read anything else in the catalogue.
See all 4 Overhead Line Conductor & Aerial Bundled Cable constructions →
Building wire is the highest-volume, lowest-margin cable in an export catalogue, and it is where the designation matters most. A 2.5 mm² copper conductor with PVC over it is called BV, BVR, H07V-R, THHN or RV depending on which standard the project follows, and each name implies a different voltage class, a different stranding class and a different list of tests. Getting the name right is most of the conversion.
See all 5 Building Wire & Hook-Up Wire constructions →
Selection notes — Overhead Conductor & Building Wire
What decides the size of a solar DC cable: voltage drop, not current
String current is set by the short-circuit current of the module, so moving from 1000 V to 1500 V does not change the conductor that the current rating demands. What changes is the permitted voltage drop. At the same power, a 1500 V string carries roughly two-thirds the current of a 1000 V string, so a 4 mm² run that loses 3% at 1000 V loses closer to 2% at 1500 V over the same distance.
The calculation to do before ordering takes the string length, multiplies by the current at maximum power, and divides by the loop resistance the cross-section gives. EN 50618 cable is tabulated by DC resistance at 20 °C, but it works at 70–90 °C, where copper resistance rises by about 0.4% per kelvin. Size for the hot resistance, then check the short-circuit temperature covers the array fault current.
- Ask for the DC loop resistance in Ω/km, not only the cross-section in mm²
- Use the resistance at +90 °C, not the 20 °C table value
- Keep DC loss between 1.5% and 2% from module to inverter
- Confirm the 250 °C for 5 s short-circuit rating covers the array fault current
How do you choose a rubber cable for a machine that moves?
Flex life is a function of bending radius, cycle speed and compound. A cable dragged over a steel floor at 30 m/min needs a sheath that resists abrasion and a conductor that survives repeated bending. Class 5 stranding to IEC 60228 is the minimum; on festoon and reeling duty the lay length of the strands matters as much as the strand count, because that is what controls where the fatigue crack starts.
Then separate the oil question from the weather question. Nitrile and CPE compounds hold up against mineral oil but stiffen and crack under ozone. PCP and EPR handle weather and ozone but swell in oil. A port crane that works outdoors and leaks hydraulic fluid needs both, which is why the sheath compound belongs on the enquiry first, not last.
- State the minimum bending radius the installation allows, as a multiple of overall diameter
- Give the cycle rate and the travel speed in m/min
- Name the oil type: mineral, hydraulic, or vegetable based
- Say whether the run is indoors, outdoors, or both
Span length and tensile load: what a bare conductor is actually bought on
A bare overhead conductor is a structural component as much as an electrical one. The electrical figure you need is DC resistance in Ω/km. The structural figures are the rated tensile strength in kN, the mass in kg/km, and the sag-tension behaviour of the span you are stringing. All three are tabulated in IEC 61089, and all three change with the alloy and the stranding.
AAC uses 1350-O aluminium at roughly 160 MPa. AAAC uses a 6201-T81 alloy that close to doubles the tensile strength at the same diameter, which buys a longer span or fewer poles. ACSR puts galvanised steel in the middle of the conductor, so aluminium carries the current and the steel carries the tension. That is the entire reason ACSR exists.
- Compare breaking load in kN, not cross-section alone
- Ask for the sag-tension table for your ruling span
- Check the galvanising class on the steel core: Class A minimum
- Remember bare conductor is traded by weight and priced against the aluminium index
450/750 V or 600 V: which standard does your inspector quote?
The same 2.5 mm² copper conductor is called BV on an IEC-aligned project and THHN on an Americas project, and on paper the two are not interchangeable. IEC-type wire is rated 450/750 V, uses a PVC/C compound, and is referenced to GB/T 5023 or IEC 60227. UL wire is rated 600 V, carries a nylon jacket over the PVC, and is referenced to UL 83.
The electrical difference is small; the paperwork difference decides whether the job passes. A project in the Gulf or Southeast Asia following IEC will ask for BV or BVR. A project in Chile, Mexico or the United States following NEC will ask for THHN/THWN-2 with a UL listing mark on the drum. Quote the designation the tender document uses and the inspection closes without argument.
- Read the voltage class in the tender: 450/750 V means IEC, 600 V means UL
- For the Americas, name THHN or THWN-2 and give the UL file number
- For Europe, Asia and the Middle East, name BV, BVR, RV, H07V-U or H07V-R
- Ask whether a nylon jacket is required: under UL 83 it is
Request pricing across the Overhead Conductor & Building Wire range
Include cross-section, core count, voltage grade, route length and installation method — those five determine price more than anything else on the page.
- Engineer-reviewed before pricing
- Reference drawings issued with the quotation
- Free sample up to free sample up to 5 m