What do wire numbers like 7/29 mean in Pakistan?

How does the code work — what do the two numbers mean?

The wire number meaning in Pakistan is mechanical, not electrical: strands / strand diameter in inches. The first number counts the strands twisted into the conductor. The second is each strand's diameter in thousandths of an inch, with the decimal dropped in speech — properly written 7/.029, said "7/29", printed either way. So the 7/29 wire meaning, in full, is seven strands of 0.029 inch wire laid up as one conductor.

The metal follows from the strand. Convert the diameter: 0.029 inch × 25.4 = 0.74 mm. One strand's cross-section: π ÷ 4 × 0.74² = 0.43 mm². Seven of them: 7 × 0.43 = 3.0 mm². That is the whole system — strand count times strand area. It also settles a common misreading: the codes are not fractions. 7/64 is not seven sixty-fourths of anything; it is seven strands of 0.064 inch.

Pakistani wire codes such as 3/29, 7/29, 7/36, 7/44, 7/52 and 7/64 describe the conductor's construction: the first number is how many strands the conductor contains, and the second is the diameter of each strand in thousandths of an inch. So 7/29 is seven strands of 0.029 inch (0.74 mm) wire, which computes to about 3.0 mm² of metal and is sold in Pakistan as 2.5–3 mm² cable. 7/36 is seven strands of 0.036 inch, about 4.6 mm², sold as 4 mm². 3/29 is three strands of the same 0.029 inch wire, about 1.28 mm², sold as 1.5 mm². 7/52 and 7/64 compute to about 9.6 mm² and 14.5 mm²; in Pakistan those two codes usually mean aluminium service cable — the sizes people call WAPDA cable. The code states construction only; the current rating follows from the metric size and the metal, not from the code itself.

Which wire is which? The chart from 3/29 to 7/64

These are the wire gauge numbers Pakistan runs on, from the smallest house-wiring code to the service drop. The 3/29 7/29 7/36 7/44 wire chart below carries the two service codes, 7/52 and 7/64, as well — each code links to its datasheet.

The capacity belongs to the metric size and the metal, never to the code — the code is only a build sheet. Full ratings across every size are on the current capacity chart. And note what this chart is not: 3/29 and 7/36 are strand codes, not SWG numbers. If you are converting SWG gauges to mm², that job belongs to the wire size chart (SWG–mm²).

Why does 7/29 compute to 3.0 mm² but sell as 2.5 mm?

Because the codes are imperial and the metric sizes are IEC 60228 nominal areas — two scales that do not land on each other. 7/29's computed 3.0 mm² sits between the 2.5 and 4 nominal sizes, so it is sold as 2.5 mm² — or labelled "3 mm" by some makers: same wire, bolder label. 7/36 computes to 4.6 mm² and sells as 4 mm²; 7/44 computes to 6.9 mm² and sells as 6 or 7. The metric name is the size class the cable is priced and rated at, not a measurement of the coil in your hand.

That gap is also where wire gets cheated. The computed area assumes every strand is genuinely full gauge — a 7/29 with seven strands truly 0.029 inch each. Draw the strands a few thousandths under and the label stays the same while the copper shrinks. The check is mechanical, and anyone can do it at the counter: count the strands at the cut end, and measure one with a vernier if you carry it — 0.029 inch is 0.74 mm. What full gauge means, and how we hold it, is set out on the 100% copper wire page.

What is WAPDA cable — the 7/52 and 7/64 codes?

If you searched the 7/52 7/64 WAPDA cable meaning, it is this: seven strands of 0.052 inch is about 9.6 mm², sold as 10 mm²; seven strands of 0.064 inch is about 14.5 mm², sold as 16 mm². In Pakistan those two codes almost always name aluminium service cable — the black cable that runs from the pole to the meter and on to the distribution board. The trade calls it WAPDA cable because service connections are where these sizes live, not because any utility brands it.

It comes as 2-core for a single-phase connection and 4-core for three-phase. Aluminium carries less current than copper at the same size, so the working figures sit below the copper column in the chart above:

Datasheets: 7/52 10mm 2-core aluminium and 7/64 16mm 2-core aluminium, with the three-phase versions at 7/52 4-core and 7/64 4-core.

How do you read a coil label?

• One wire, three names. The sheath print may say 7/.036, the label card 4 mm², and the shopkeeper "7/36" — all the same wire. 7/.029 and 7/29 are likewise the same code with the decimal dropped.
• Check the metal. Copper and aluminium look alike under black PVC at a glance; the label states which it is. At 7/52 and 7/64 sizes, expect aluminium unless the label says otherwise.
• Count and measure. At the cut end the strands are countable — three or seven for these codes — and a vernier settles the diameter: 0.029 inch is 0.74 mm, 0.036 inch is 0.91 mm.
• The voltage figure is not a size. 450/750 V printed on fixed-wiring PVC cable is the insulation's voltage class, the same on every size here.
• Ask the coil length with the rate. Coil lengths differ between makers, and two quotes cannot be compared until both name their metres.

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