Cable testing: what we check, and what needs a laboratory

PILONE CABLES TECHNICAL TEAM

Pilone Cables is not an accredited test laboratory and issues no test report. What we do, on request, is measure conductor size, strand count and resistance on a coil drawn on our Lahore line.

The reading is compared with the IEC 60228 limit for that size and class — 4.61 Ω/km for 4 mm² class 2, 7.41 for 2.5 mm², 1.15 for 16 mm². That is a factory verification, and it is worth exactly what an honest measurement is worth: it tells you the conductor is the size on the label. Anything that has to carry a stamp — type tests, insulation and voltage withstand, flame tests — belongs to an accredited laboratory, not to the manufacturer of the cable.

What we can check

CONDUCTOR

Strand count and size

Count the strands and measure one: 7/0.85 is a 4 mm² class 2 conductor, 56/0.30 is the class 5 flexible build of the same size.

RESISTANCE

Conductor resistance

Measured on a known length and converted to ohms per kilometre, then read against the IEC 60228 limit in the table below.

Maximum conductor resistance at 20°C per IEC 60228. Class 2 is the stranded conductor in fixed wiring cable, class 5 the finer-stranded flexible conductor. The 10 m column is the class 2 limit × 0.01, for checking a sample rather than a whole coil.
Size	Class 2 strands	Class 2 max Ω/km	Max Ω on a 10 m sample	Class 5 max Ω/km
1.5 mm²	7/0.53	12.1	0.121	13.3
2.5 mm²	7/0.67	7.41	0.0741	7.98
4 mm²	7/0.85	4.61	0.0461	4.95
6 mm²	7/1.04	3.08	0.0308	3.30
10 mm²	7/1.35	1.83	0.0183	1.91
16 mm²	7/1.70	1.15	0.0115	1.21
25 mm²	7/2.14	0.727	0.00727	0.78

The reading is taken at the Lahore factory, Mon–Sat 09:00–18:00. Send the size and the invoice on WhatsApp first so we know which coil and which limit applies.

How the resistance check is done

Resistance is the only conductor property a standard defines as a hard number, which is why it is the one worth measuring. A purity percentage cannot be read off a meter; ohms can. Measure a known length of the conductor, divide by that length in kilometres, and compare.

Worked example. A 10 m sample of what was sold as 4 mm² class 2 measures 0.052 Ω. Convert: 0.052 ÷ 0.010 km = 5.2 Ω/km. The IEC 60228 limit for that conductor is 4.61 Ω/km, so the sample is 13% above the limit and the conductor is not a 4 mm² class 2 conductor, whatever the sheath says. Had it measured 0.045 Ω — 4.5 Ω/km — it would sit inside the limit.

Two cautions on the reading. The limits are set at 20°C and copper resistance climbs with temperature, so a sample measured in a hot workshop reads high and needs correcting before anyone calls a pass or a fail. And a cheap multimeter is near its floor at these values — 0.0115 Ω for a 10 m sample of 16 mm² is smaller than the resistance of most test leads, so the lead resistance has to be measured and subtracted, or a four-wire measurement used.

What we cannot do

Stated plainly, because the alternative is a page of implied credentials. Pilone Cables holds no third-party test report and publishes none. We do not run type tests, insulation thickness or insulation resistance tests, high-voltage withstand tests, or any flame or smoke test. We issue no certificate, and a measurement we hand you is our word, not an accredited result.

If a tender or an inspector needs a report, an accredited testing laboratory is the right route and a manufacturer checking its own cable is not a substitute for one. What we can honestly offer is the spec for every size we draw, and a measurement on a coil that came off our line.

Before you sign for a coil

1. Read the sheath against the quote

Size, core count and voltage rating are printed along the sheath. Fixed wiring cable in PVC is a 450/750 V cable; light flexible cord is 300/500 V. If the print and the invoice disagree, stop there.

2. Count the strands and check the build

Seven thick strands is a class 2 fixed-wiring conductor; dozens of fine strands is class 5 flexible. 7/0.85 and 56/0.30 are both 4 mm², but they are not interchangeable in a terminal.

3. Confirm the metres, then the resistance

Cut a known length — 10 m is enough, and the table above gives the limit for that length. Anything shorter and lead resistance swamps the reading. Once you have it, bring the coil or a 10 m offcut to the Lahore factory and we take the resistance reading with you.

Checking whether the metal is really copper rather than copper-clad aluminium is a different measurement again — it is a mass check, not a resistance check, and the method is on how to check the conductor yourself. The wider list of questions worth putting to any supplier is on choosing a cable company in Pakistan.

A conductor that meets its resistance limit is still only correct for a circuit if it is sized for the load. Current capacity figures on this site assume BS 7671 reference method C (clipped direct), 30°C ambient, PVC — derate for conduit, grouping and higher ambient. Have a licensed electrician confirm the size for your load and run length, or start with the cable size calculator.

Frequently asked

Do you provide a cable test certificate?

No. We hold no third-party test report and we issue none. What we provide is the published conductor spec for the size you bought and, on request, a measurement of conductor size and resistance on a coil from our line. For a certificate that an inspector or a tender will accept, use an accredited testing laboratory.

How do I know the coil I received is the size I ordered?

Three readings settle it. The sheath print should carry the size, cores and voltage rating. The strand build should match the class — 7/0.85 for 4 mm² class 2, 56/0.30 for class 5. And the conductor resistance should sit under the IEC 60228 limit for that size, 4.61 Ω/km in the case of 4 mm² class 2.

Can I check conductor resistance with an ordinary multimeter?

Not reliably. The values are tiny — a 10 m sample of 16 mm² has a limit of 0.0115 Ω, smaller than the resistance of most test leads. Short the leads together, read that figure and subtract it, or use a four-wire measurement. Correct for temperature as well: the limits are set at 20°C and copper reads higher in a hot workshop.

Do you need the whole coil, or is a sample enough?

A sample is enough for the resistance check. Ten metres cut from the coil gives a reading big enough to trust, and the table above carries the limit for that length. Bring the whole coil if you want the metres confirmed too, because coil length can only be checked by measuring the coil itself. Either way, bring the invoice.

Can you test cable I bought somewhere else?

Our verification covers coils drawn on our own line, because that is the only cable whose history we know. On anything else we will tell you what to measure and the number it has to meet, and the limits table above is the same for every maker. A reading we did not take is not a result we can stand behind.

What does a proper cable test report cover?

An accredited laboratory typically works from sampled lengths and covers conductor resistance, insulation and sheath thickness, insulation resistance, a voltage withstand test, and the flame tests specified for that cable type. It is a different exercise from a factory measurement, and only the laboratory's report carries weight with a third party.

FACTORY-DIRECT · LAHORE

Ask before you buy, or check what arrived

Send the size and the invoice on WhatsApp, then bring the coil or a 10 m offcut to the Lahore factory and we take the conductor and resistance reading with you. Mon–Sat, 09:00–18:00.

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