Power cable: eight steps
A 0.6/1 kV or medium voltage power cable passes through the same core sequence in every cluster. The plant layout differs, and some steps are bought in, but the order does not change. The table maps each step to the check the desk asks for.
| Step | What happens | Check that belongs to it |
|---|---|---|
| 1. Drawing | Copper or aluminium rod is drawn down to wire and annealed | Wire diameter, annealing, incoming rod records |
| 2. Stranding | Wires are stranded and often compacted into a Class 2 conductor; Class 5 for flexible cable | Number of wires, conductor diameter, DC resistance to IEC 60228 |
| 3. Insulation extrusion and cross-linking | PVC or XLPE is extruded over the conductor; XLPE is cross-linked by silane curing or a continuous vulcanisation line | Insulation thickness, eccentricity, spark test, hot set for XLPE |
| 4. Cabling | Cores are laid up with fillers and binder tape; MV cores get screens first | Lay length, core identification, roundness |
| 5. Armouring | Steel tape, steel wire or aluminium wire armour over an inner sheath | Armour coverage and wire count, armour resistance |
| 6. Sheathing | PVC, LSZH or PE outer sheath is extruded | Sheath thickness, overall diameter, surface |
| 7. Marking | Ink-jet or embossed sheath print and metre marks | Print text against spec sheet, metre mark accuracy |
| 8. Testing | Routine tests per drum, sample tests per batch | Resistance, voltage, partial discharge for MV |
Conductor and insulation: where most of the cost sits
Drawing and stranding set the conductor, and conductor resistance is the single most useful figure on a test sheet: for copper Class 2, IEC 60228 limits 25 mm2 to 0.727 ohm/km and 95 mm2 to 0.193 ohm/km at 20 C. Insulation extrusion sets thickness and concentricity. XLPE must be cross-linked to reach its 90 C continuous and 250 C short-circuit ratings; small LV sizes are often silane-cured, while MV cable runs on a continuous vulcanisation line with conductor screen, insulation and insulation screen applied in one triple extrusion head. That triple head is why MV cable cannot be made on an LV plant's line. See insulation and sheaths and MV power cables.
Cabling, armour and sheath
Cabling lays the cores together with fillers into a round shape. For armoured cable, an inner sheath goes on first, then steel tape (STA), steel wire (SWA) for multicore or aluminium wire (AWA) for AC single core, and finally the outer sheath. Each extra layer adds a line pass, which is one reason armoured and MV cable take longer to schedule. Sheath compound decides fire and smoke behaviour, so LSZH or flame-retardant PVC is fixed on the spec sheet and backed by a report on the finished cable.
Marking and testing
Marking is applied on the sheathing line or a separate printing pass: brand or private label text, construction, standard, year and metre marks. A miscounted metre mark becomes a short drum on site, so the desk checks calibration. Routine tests follow on every drum: conductor resistance, voltage test (for MV, 3.5 U0 for 5 minutes under IEC 60502-2) and partial discharge to IEC 60885-3 for MV. Sample tests such as thickness, hot set and diameter run per batch. The detail is on quality control.
Fibre cable: colouring, tubing, stranding, sheathing
Optical cable plants start from drawn and coated fibre, either their own or bought from a fibre maker, and add the protection around it.
- Colouring: each fibre receives a UV-cured colour to the TIA-598 sequence or the buyer's code, taking a 242 um coated fibre to about 250 um.
- Tubing: fibres are fed into a loose tube with gel, or tight-buffered to 0.9 mm for indoor cable; excess fibre length in the tube is controlled here.
- Stranding: tubes and fillers are stranded around a central steel wire or FRP member, with water-blocking materials.
- Sheathing: armour tape such as PSP or APL where specified, then PE or LSZH sheath, with print and metre marks; aramid yarn for ADSS and indoor cable.
After sheathing, each drum is measured by OTDR for attenuation and length. Attenuation is reported against the datasheet values for the fibre type; for G.652.D, the cabled fibre limits in the G.652 tables are 0.4 dB/km at 1310 nm and 0.3 dB/km at 1550 nm.
What this means for your order
Lead time follows the slowest step: copper booking and line slots for power cable, fibre and tube scheduling for optical cable, plus routine tests and drum supply. The desk confirms each in writing; see MOQ and lead time or start with the quote form.