Decision 1: low or medium voltage
Low voltage power cable at 0.6/1 kV covers feeders and sub-mains in buildings, plants and solar balance of system; the rating means 0.6 kV to earth and 1 kV between conductors, with 1.2 kV as the highest system voltage. Medium voltage cable to IEC 60502-2 runs in classes 3.6/6, 6/10, 8.7/15, 12/20 and 18/30 kV and adds a conductor screen, insulation screen and copper tape screen around thicker XLPE. The partner plant catalogue behind our MV reference reaches 8.7/15 kV; higher classes are matched to other plants. MV adds process steps and partial discharge testing, which affects lead time.
Decision 2: armoured or unarmoured
Armour protects against mechanical damage in burial, trenches and industrial routes; it does not make a cable suitable for heavy pulling tension. Multicore cable usually takes steel wire armour (SWA), to BS 5467 with a PVC sheath or BS 6724 with LSZH in the UK. AC single-core cable uses aluminium wire armour (AWA) to avoid eddy-current heating. Steel tape armour (STA) is also an allowed form in IEC 60502-1 and is what our armoured reference uses. Armour adds weight: the 4x35 mm2 STA reference is about 2,067 kg/km.
Decision 3: copper or aluminium
Aluminium conductors cut weight and metal cost on large feeders. The 4x95 mm2 aluminium reference weighs about 1,907 kg/km, and its IEC 60228 limit of 0.320 ohm/km is close to copper 50 mm2, so an aluminium cable is usually upsized by your engineer. Small aluminium sizes are not offered; multicore aluminium typically starts at 10 mm2. Terminations, lugs and local rules must suit aluminium.
Decision 4: fire performance
Three properties are often confused. Flame retardance is tested to IEC 60332-1-2 on a single cable or IEC 60332-3 on bunched cables. Low smoke zero halogen behaviour is tested to IEC 61034 and IEC 60754-1/-2. Circuit integrity, keeping power on during a fire, is tested to IEC 60331, BS 6387 CWZ or BS 8519. In the EU, cable permanently installed in buildings also needs a CPR class declared on the DoP, which describes reaction to fire only. Ask for each property by name, per test report; see fire-resistant cables.
Decision 5: solar DC cable
Solar strings use single-core cable such as H1Z2Z2-K to EN 50618 and IEC 62930, with tinned Class 5 copper and cross-linked halogen-free insulation and sheath, rated DC 1.5 kV; US projects use UL 4703 PV Wire. PV1-F has been superseded by H1Z2Z2-K. Coils of 100 m and 500 m drums are usual; see solar PV cables.
Decision 6: market and standard
Pick the standard before the plant. IEC 60502-1 suits most export markets; the UK, US, Thailand, South Africa and Saudi Arabia have their own routes, listed in the cable standards guide. A construction that is correct to IEC 60502-1 may still be refused on a UK site that specifies BS 6724, or on a US job where the AHJ expects UL-listed products. The plant must hold the reports or listing for that exact construction and size range, so the desk checks the certificate scope before shortlisting rather than after a sample has been made.
Write down the cluster preference only if it matters to you. Power and special cables are made mainly in Yixing and Guanlin, Ningjin and Wuwei; the desk shortlists by construction, standard and test capability, which often matters more than location.
Spec sheet fields to fix in writing
| Field | Example entry | Why it matters |
|---|---|---|
| Voltage and standard | 0.6/1 kV, IEC 60502-1 | Sets insulation thickness and tests |
| Cores and size | 4x25 mm2 or 3x95+1x50 mm2 | Basis of copper weight and price |
| Conductor | Annealed copper, Class 2, IEC 60228 | Resistance limit used for checks |
| Insulation | XLPE, nominal thickness per standard | Temperature rating and cost |
| Armour and screen | STA, SWA, AWA, copper tape or none | Weight, earthing, lead time |
| Sheath | PVC, LSZH or PE; colour | Fire tests, UV and site rules |
| Fire properties | IEC 60332-1-2; CPR class on the DoP | Which reports must exist |
| Marking | Brand, construction, standard, year, metre marks | Checked on every drum |
| Drum plan | Length per drum, drum type, end caps | Site pulls and freight weight |
Routine tests to ask for per drum
- Conductor DC resistance at 20 C against IEC 60228.
- Spark test or voltage test on insulation and sheath; for MV, the IEC 60502-2 routine test at 3.5 U0 for 5 minutes.
- Partial discharge for MV, at 1.73 U0 with sensitivity of 10 pC or better, method to IEC 60885-3.
- Dimensions: insulation and sheath thickness and overall diameter, on sample tests.
- Print and metre marks against the agreed text, and drum length against the ledger.
Type tests such as thermal ageing and fire tests sit in the plant's reports; the desk checks which constructions and dates they cover. Typical MOQs are on MOQ and lead time.