WAPDA cable: which size for your meter connection

What the name actually means

WAPDA cable is the Pakistani trade name for the aluminium meter cable that runs between an electricity meter and a distribution board, and the same product is sold as silver cable — after the grey-white colour of the aluminium conductor, not because there is any silver in it — or simply as meter wire. It is stocked mainly in two strand codes: 7/.052, which computes to 9.6 mm² and is sold as 10 mm², and 7/.064, which computes to 14.5 mm² and is sold as 16 mm². Neither name is a specification, an approval or a standard — it is shop vocabulary for a size and a construction, and reading it as an endorsement is where buyers go wrong.

Two core is a single-phase 220 V connection, live and neutral; four core is three-phase 400 V, three phases and a neutral. Your connection paperwork states which you hold and the sanctioned load in kW that this page turns on. The copper version of the same run is on the main meter cable page; the circuits leaving the board are sized on the single-phase and three-phase pages.

7/.052 kitne mm ka hota hai? Trade code to true size

Strand codes are imperial: 7/.052 is seven strands of 0.052 inch. Work the geometry and the areas do not land on the metric sizes the cable is sold as — what you buy as 16 mm² is 14.5 mm² of aluminium. That is arithmetic, not an accusation, and it is why capacity rather than label is the thing to size against.

Sanctioned load to size, single-phase 220 V

Current is load divided by voltage. The cable is then chosen so its capacity after correction clears that current — the table figure is a 30°C number, and a service cable on an outside wall in Pakistan is not at 30°C.

The copper alternative in stock: 16mm 2 core cable · 25mm 2 core cable

Where the market default fails: 10 kW on 7/.052

A 10 kW single-phase connection draws 10000 ÷ 220 = 45.5 A. The size the shop hands over for that job is 10 mm² aluminium — the cable everyone calls WAPDA cable — and at 30°C it is rated 48 A, so on paper it clears by about 5%.

Now put the run where it actually goes: up an outside wall in a Lahore June. The BS 7671 ambient correction for 70°C PVC at 40°C is 0.87, so 48 × 0.87 = 41.8 A — below the 45.5 A the connection draws. The default size has become the weakest part of the connection. 7/.064, the 16 mm², is rated 66 A, corrects to 57.4 A and still clears the load with about 12 A in hand.

Voltage drop says the same thing. Over a 15 m run, at the IEC 60228 conductor resistance of 3.08 Ω/km, 10 mm² aluminium drops 2 × 45.5 × 3.08 × 15 ÷ 1000 = 4.20 V — most of a 6.6 V budget (3% of 220 V) spent before a single house circuit is fed. 16 mm² at 1.91 Ω/km drops 2.61 V.

Three-phase 400 V connections

On three phases the current spreads across them: 25 kW draws 25000 ÷ (1.732 × 400 × 0.9) = 40.1 A per phase at 0.9 power factor. 16 mm² 4 core clears that after correction; 10 mm² does not. Read the corrected column, not the 30°C one.

Metres, not coils

Measure the route the cable takes, not the straight line: down from the meter board, along the wall or trench, into the house and up to the board, plus a metre of slack at each end. Most houses land between 8 and 15 metres. Service cable is sold by the coil and coil lengths differ between makers, so ask for the coil length with the rate — a quoted silver cable price in Pakistan is usually a coil price, and a 12 m run does not need a coil. A cut length costs less.

Sizes and rates: 10mm aluminium cable price · 16mm aluminium cable price · 25mm aluminium cable price

If the run goes underground

A buried stretch between the meter pillar and the house wants armour — a steel-wire layer that takes soil pressure, spades and rodents. It also wants a second derating step, because earth around a cable does not shed heat the way open air does. Size it for the buried section, not the wall section.

Cable for an underground run · Armoured cable, 4mm² to 95mm²

Frequently asked