Single phase, 220 V, about 26 A: 6 mm² to 58 m, 10 mm² to 96 m, 16 mm² to 151 m, 25 mm² to 242 m, on a 40 A type C MCB. Three phase, 400 V, about 8.3 A per line: 2.5 mm² four-core reaches 154 m and 4 mm² reaches 253 m, on a 16 A type C MCB.
At 5 HP the cable stops being a detail. A long single-phase tubewell run at this size is usually the largest single line item in the whole job, and the same motor on a three-phase connection needs a fraction of the copper. Read the nameplate for the phase and the full-load current, measure the whole route including bore depth, then read the size. Metres are one way, on a 5% voltage-drop budget.
5 HP on single phase: 26 A, and the run length that decides it
Five horsepower is 3,730 W of shaft output, not of input, and the difference lands on the supply as current — which is why a 5 HP plate on 220 V typically reads near 26 A rather than the 17 A that dividing 3,730 by 220 suggests. A 5 HP single-phase motor at 26 A needs 6 mm² copper on any run up to 58 m, 10 mm² from there to 96 m, 16 mm² to 151 m and 25 mm² to 242 m — each figure being the length at which voltage drop reaches 5% of a 220 V supply, with the circuit on a 40 A type C MCB and the cable clipped direct at 30°C. 6 mm² is the floor whatever the length: 4 mm² is rated 36 A and will not sit under a 40 A breaker.
Volts lost in the cable at an assumed full-load current of 26 A on a 220 V single-phase supply. Figure = mV/A/m × 26 A × run ÷ 1000; the budget is 5% of 220 V, which is 11 V. Run is one way, along the route the cable takes. Copper, PVC; two loaded conductors. Voltage drop and current capacity per BS 7671, reference method C (clipped direct), 30°C ambient; conductor data per IEC 60228. The assumed current is a typical plate figure — use the full-load current printed on your own motor if it differs. Verify sizing with a licensed electrician for your installation.
Total run
Size
Trade code
Volts lost
Drop
10 m
6 mm²
7/.044
1.90 V
0.9%
25 m
6 mm²
7/.044
4.75 V
2.2%
50 m
6 mm²
7/.044
9.49 V
4.3%
75 m
10 mm²
7/.052
8.58 V
3.9%
100 m
16 mm²
7/.064
7.28 V
3.3%
150 m
16 mm²
7/.064
10.92 V
5.0%
200 m
25 mm²
—
9.10 V
4.1%
The 100 m row is where the money is. On 10 mm² the loss is 4.4 mV/A/m × 26 A × 100 m ÷ 1000 = 11.44 V, or 5.2%, just past the budget. On 16 mm² it is 2.8 × 26 × 100 ÷ 1000 = 7.28 V, or 3.3%. That one step costs real copper — the conductor in 16 mm² runs 142.2 kg per km against 88.9 kg for 10 mm² — which is why a 5 HP tubewell deserves the measurement before the order, not after. Other horsepowers are on the submersible pump cable size chart.
5 HP on 400 V three phase: 8.3 A per line
Most 5 HP tubewells are three phase, and that is the right way round. Here is the conversion in the open. On single phase the motor takes 220 V × 26 A = 5,720 VA from the supply. Feed the same machine from 400 V three phase and that becomes 5,720 ÷ (1.732 × 400) = 8.3 A per line, assuming efficiency and power factor are unchanged. The drop budget also rises, to 5% of 400 V, which is 20 V. Your nameplate beats this estimate; real 5 HP three-phase plates usually sit a little under 8.3 A.
Longest one-way run on a 400 V three-phase supply at an assumed 8.3 A per line, keeping voltage drop inside 5% of 400 V (20 V). Derived as 20,000 mV ÷ (three-phase mV/A/m × 8.3 A). The three-phase mV/A/m is 0.866 of the tabulated two-core figure — using the two-core column on a three-phase run gives the wrong answer. Current capacity is three loaded conductors, BS 7671 reference method C (clipped direct), 30°C ambient, copper, PVC; conductor data per IEC 60228. Verify sizing with a licensed electrician for your installation.
Size
Trade code
Two-core mV/A/m
Three-phase mV/A/m
Capacity, 3 loaded
Longest run at 8.3 A
1.5 mm²
3/.029
29
25.1
17.5 A
96 m
2.5 mm²
7/.029
18
15.6
24 A
154 m
4 mm²
7/.036
11
9.5
32 A
253 m
6 mm²
7/.044
7.3
6.3
41 A
382 m
Compare the two tables and the case makes itself: 100 m of single-phase 5 HP run wants 16 mm², and the same 100 m on three phase sits inside 2.5 mm². Four cores are needed — three phases and an earth — and 2.5 mm² is the sensible mechanical floor even where 1.5 mm² clears the sums. Wider three-phase feeder sizing is on three-phase cable size.
Use the single-phase table if the plate says 220 V and the three-phase table if it says 400 V — mixing the two currents and budgets produces an answer that is wrong in one direction or the other. Fit a starter with an overload relay set from the nameplate, dry-run protection, and phase-failure protection on three phase; a three-phase motor running on two phases burns out quickly. Capacities assume clipped direct at 30°C, so derate for conduit, burial, grouping and Pakistani summer ambient. If the pump hangs in a borehole, the submerged length must be drop cable with an immersion rating stated by its maker. Have a licensed electrician confirm the size, the breaker and the earthing for your installation, or start with the cable size calculator and the voltage drop calculator.
Breaker, starter and starting current
Single phase: 40 A type C MCB on a dedicated way, with 6 mm² (46 A) as the smallest cable the circuit allows. Three phase: 16 A type C triple pole, with 2.5 mm² four-core (24 A on three loaded conductors) as the practical floor.
Starting is the real test at this size. A direct-on-line 5 HP motor draws several times its running current for a second or two, and on a long run the voltage at the terminals collapses exactly when the motor needs the most torque. A star-delta or soft starter cuts that surge; star-delta needs six conductors run to the motor, not three.
Rural supply sags. Feeders in Punjab and Sindh often sit well under 220 V through the afternoon. The motor's power draw does not fall with the voltage, so current rises to make it up, and the percentage budget shrinks because it is a percentage of a smaller number. If your supply sags, take one size up from the table and measure at the panel with the pump running.
The earth matches the phases. Whatever the phase, the earth conductor matches the phase conductors on a pump circuit, and it bonds to the motor body and the delivery pipe.
The single-phase 5 HP size between 58 and 96 m of total run. Class 5 flexible copper, PVC insulated and sheathed, drawn on the Pilone line in Lahore. Rated 63 A on two loaded conductors clipped direct at 30°C, 4.4 mV/A/m, 88.9 kg per km of conductor.
Supply par depend karta hai. Single phase 220 volt par motor takreeban 26 amp leti hai: 58 meter tak 6 mm² (7/.044), 96 meter tak 10 mm² (7/.052), 151 meter tak 16 mm² (7/.064), aur 242 meter tak 25 mm². Three phase 400 volt par wahi motor 8.3 amp leti hai, to 154 meter tak 2.5 mm² char core kaafi hai.
Is 10mm cable enough for a 5 HP motor?
On single phase, out to 96 m of total run. 10 mm² carries 63 A against a 26 A load, so heat is never the limit; voltage drop is. At 96 m the loss reaches the 11 V budget. Past that take 16 mm² to 151 m or 25 mm² to 242 m. On a 400 V three-phase supply, 10 mm² is far more cable than a 5 HP motor ever needs.
What MCB size for a 5 HP motor?
Single phase at 26 A: a 40 A type C MCB, which makes 6 mm² at 46 A the smallest cable allowed on the circuit — 4 mm² at 36 A does not clear it. Three phase at 8.3 A per line: a 16 A type C triple pole. The breaker protects the cable; the overload relay in the starter, set from the nameplate, protects the winding.
Does a 5 HP three-phase motor need less cable than single phase?
Much less. Single phase at 26 A on a 100 m run wants 16 mm². The same output on 400 V three phase draws about 8.3 A per line against a 20 V budget, and 2.5 mm² four-core covers 154 m. That is the strongest argument for taking a three-phase connection on any tubewell of this size.
Why does my 5 HP tubewell trip on starting?
Direct-on-line starting draws several times the running current for a second or two, and on a long undersized cable the voltage at the motor collapses just as it needs the most torque. Check the size against the total run first, then the supply voltage at the panel with the pump running. A star-delta or soft starter cuts the surge, and star-delta needs six conductors to the motor. See voltage drop problems.
How much cable does a 5 HP tubewell job need?
Add three runs: the depth the pump hangs at, the wellhead to the starter panel, and the panel back to the board. Multiply feet by 0.3048 for metres, then add a working allowance at each termination. At 5 HP that total is the largest single line item in the job, so measure it before you price it.
Send the phase, the depth and the total run
We draw the copper in Lahore and sell it at the day's rate — no dealer margin. Tell us whether the plate says 220 V or 400 V, the nameplate current, the bore depth and surface run, and your city. One message comes back with the size and the number: Punjab in 1–2 days, rest of Pakistan in 2–4.
