Manuals · DC / AC cable
The jacket is the product. PVC “solar” is two summers.
Covers FAST XLPO, Pakistan Cables XLPO, Newage solar DC. Brand pages: FAST, Pakistan Cables, Newage. Calculator sizes mm² from voltage drop — this page is how you land it without a fire.
What XLPO is
Cross-linked polyolefin, tinned copper, EN 50618 / IEC 62930. It is meant to sit on a 70 °C roof in Multan and not crack. PVC household cable with a “solar” sticker is not that. If the jacket has no print (size, XLPO/EN 50618, manufacturer), treat it as skip.
Size (house rules of thumb)
| Size | Typical job | Street band (FAST class) |
|---|---|---|
| 4 mm² DC | Short 3 kW strings only | Rs 150–280 / m |
| 6 mm² DC | 5–6 kW house default | Rs 250–465 / m (often 340–380) |
| 10 mm² DC | 10 kW or a long roof run | Rs 400–645 / m |
| 16 mm² DC | 15 kW+ / fat C&I strings | Rs 700–990 / m |
Voltage drop: keep DC drop under ~3% at Imp. A 6 kW array on 4 mm² across a 25 m run is how you donate watts to heat. Battery DC (51.2 V, 100 A) is a different world — that is 25–35 mm² or the inverter’s busbar kit, not leftover 6 mm² PV wire.
Polarity and colour
Red +, black − is the Pakistani convention on DC. Mark both ends. A reversed string at the isolator is a dead MPPT or a reverse-current surprise. Do not rely on “I remember which is which.”
MC4
- Same family both ends of a connection. Stäubli-to-clone is a contact that heats.
- Crimp with the right die. A pliers “crush” is a warranty void and a hot spot.
- Click until it locks. Tug test. A resting connector is the August smell.
- Strain relief: the cable should not hang on the latch. Clip it to the rail.
- Do not open MC4 under load. Isolator OFF first. DC arc does not self-extinguish like a 230 V spark.
Routing
UV-exposed, but not a tripwire on the terrace. Drip loops so rain does not run into the junction box or isolator. No sharp GI edges chewing the jacket — grommet or sleeve. Indoor AC from inverter to DB is PVC/XLPE house wire sized for the AC amps, in conduit, with an MCB that matches. Earth with the rest of the stack.
Never
- Join XLPO to PVC with a tape ball on the roof.
- Use speaker wire, “inverter cable” from a UPS stall, or unmarked coil for PV.
- Share one undersized run for two MPPTs “to save copper.”
- Ignore a hot MC4. Isolator off, then look. Faults.