Single-core or multi-core cable — which build does the job need?

PILONE CABLES TECHNICAL TEAM

Single-core for anything pulled through conduit. Multi-core wherever the cable runs on its own — the submain, three-phase feeders, motor runs and appliance tails.

Single-core is one conductor with one layer of insulation, sold by the coil — usually 90 m, but ask — and drawn loose down a pipe. Multi-core is two, three or four insulated cores under a common outer sheath, so one pull gives you the whole circuit including the earth. Neither carries more current for the same copper. What changes is how many loaded conductors end up sitting together, and that is what sets the current rating — 36 A at 4 mm² with two, 32 A with three.

What each build actually is

Clear one thing up first, because it costs people money at the counter: single-core does not mean solid. Single-core describes how many conductors are in the cable — one. Solid describes whether that conductor is one wire or many strands twisted together. A 4 mm² single-core building wire is stranded, 7/0.85 to IEC 60228 class 2, and it is still single-core. If the question you are really asking is solid against stranded, that is the flexible vs solid cable guide, not this one.

In Pakistani house wiring, single-core copper in conduit is the normal build for lighting, socket and appliance points, while multi-core sheathed cable carries the submain from the meter to the distribution board, the three-phase feeders, the motor runs and the appliance tails that leave the conduit. The engineering difference is not the sheath. It is the number of loaded conductors bunched together: at 4 mm², two loaded conductors are rated 36 A and three are rated 32 A on BS 7671 reference method C at 30°C, and single cores bunched in one pipe are grouped and derated by the same physics under a different heading.

How the two builds differ in the hand and on site. Conductor classes per IEC 60228; voltage classes per Pilone spec data — 450/750 V for fixed wiring cable, 300/500 V for light flexible cords.
	Single-core	Multi-core
Conductors in the cable	1	2, 3 or 4
Outer sheath	None — insulation only	Yes, over all cores
Mechanical protection	The conduit or trunking provides it	The sheath provides it
How the trade sells it	By the coil, usually 90 m	Coil or cut length
Earth conductor	Pulled separately, sized separately	Included as the third or fourth core
Read the rating from	The grouping factor for the pipe	The loaded-core column of the table
Where it belongs	Lighting, socket and appliance points in conduit	Submains, feeders, motors, tails outside conduit
Pilone range	General wiring single-core coils	Standard and flexible cable

The number that actually changes: loaded conductors

A conductor's rating is a heat limit. Put two current-carrying conductors side by side under one sheath and each has one neighbour warming it; put three, and each has two. So the same copper is allowed less current in a three-core cable than in a two-core, and the standard prints two columns for exactly that reason. The earth core does not count — it carries no current in normal service — so a 3-core cable feeding a single-phase point is still read on the two-loaded-conductor column.

Copper, PVC, 450/750 V. Current capacity per BS 7671 reference method C (clipped direct), 30°C ambient; conductor data per IEC 60228. Derate for conduit, grouping and ambient above 30°C. The loss column is (2-core − 3-core) ÷ 2-core. Verify sizing with a licensed electrician for your installation.
Size	2 loaded conductors	3 loaded conductors	Loss	Class 2 strands
1.5 mm²	19.5 A	17.5 A	10.3%	7/0.53
2.5 mm²	27 A	24 A	11.1%	7/0.67
4 mm²	36 A	32 A	11.1%	7/0.85
6 mm²	46 A	41 A	10.9%	7/1.04
10 mm²	63 A	57 A	9.5%	7/1.35
16 mm²	85 A	76 A	10.6%	7/1.70
25 mm²	112 A	96 A	14.3%	7/2.14

Worked through: take a three-phase submain drawing 60 A. Read the three-loaded-conductor column, because all three phases carry current. 10 mm² gives 57 A and is short before any derating at all; 16 mm² gives 76 A and holds. Read the wrong column and 10 mm² looks like a 63 A cable and passes the check. That one column is the most common sizing error made on four-core cable, and it is why the three-phase cable size guide works off the three-conductor figures throughout.

Single cores dodge the sheath but not the physics. Six loaded cores pulled down one 25 mm conduit heat each other exactly as six cores under one sheath would, and BS 7671 handles it with a grouping factor instead of a second column. The factor is set by how many circuits share the pipe, so a lighting circuit and a socket circuit sharing one conduit count as two circuits, not as the five separate conductors in the pipe. Ask your electrician for the factor that applies to your conduit before you commit to a size.

The earth is the decision people get wrong

A 3-core sheathed cable hands you the earth at the same size as the live and neutral, in the same sheath, terminated at the same time. Nothing to remember and nothing to skimp. With single cores the earth is a separate purchase, a separate pull and a separate decision — and on site it is the one that gets shaved, because a thinner earth is cheaper and nobody sees it after the plaster goes on.

On a 4 mm² appliance point that means the earth should also be 4 mm², whether it arrives as the third core of a 4mm 3 core standard cable or as a separate 4 mm² single core in the same conduit. If the earth is the only thing you take from this page, take that.

Current capacity depends on how the cable is installed. The figures here are BS 7671 reference method C, clipped direct, 30°C ambient, PVC — derate for conduit, for the number of circuits grouped in it, and for ambient above 30°C. Have a licensed electrician confirm the size, the core count and the earth for your load and run length, or start with the cable size calculator.

Which build for which job

Typical Pakistani domestic and light commercial jobs. Sizes shown are the common case, not a substitute for sizing the actual load and run length.
Job	Build	Usual size
Lighting and fan points in conduit	Single-core	1.5 mm² (3/.029)
Socket and kitchen circuits in conduit	Single-core	2.5 mm² (7/.029)
AC and geyser points in conduit	Single-core	4 mm² (7/.036)
Meter to distribution board	Multi-core, 2 core	16mm 2 core cable
Three-phase submain or motor feeder	Multi-core, 4 core	25mm 4 core cable
Appliance tail outside the conduit	Multi-core flexible	4mm 3 core flexible cable
Solar string, panel to inverter	Single-core DC	6 mm² solar DC

One rule covers most of it: if the conduit protects the cable, buy single cores and pull them; if nothing protects the cable, buy the sheath. Send the size, the core count and the metres and we quote at the day's copper rate — Punjab in 1–2 days, the rest of Pakistan in 2–4.

Frequently asked

What is the difference between single core and multi core cable?

Single-core has one conductor in one layer of insulation and needs a conduit or trunking around it. Multi-core has two, three or four insulated cores under a common outer sheath, so it can run on its own and brings the earth with it. The rating changes with the number of loaded conductors: 36 A at 4 mm² with two, 32 A with three.

Single core ya multi core — ghar ki wiring ke liye kaun sa?

Ghar ke andar, jahan pipe (conduit) deewar mein dala hota hai, single core wire hi chalti hai — 3/.029 lights ke liye, 7/.029 sockets ke liye, 7/.036 AC point ke liye. Meter se DB tak, three-phase feeder, motor aur appliance ki tail ke liye sheathed multi core cable lein. Earth wire ko kabhi chhota na rakhein.

Is single-core cable the same as solid cable?

No. Single-core counts the conductors in the cable — one. Solid describes that conductor: one wire instead of many strands. Most single-core building wire sold in Pakistan is stranded, 7/0.85 at 4 mm² to IEC 60228 class 2. For the solid-against-stranded question see the flexible vs solid cable guide.

Can I run single-core cable without conduit?

No. Single-core building wire has insulation but no outer sheath, so nothing on it is meant to take abrasion, a nail or a foot. It belongs in conduit or trunking. Where a run has no protection — across a roof, down a wall, out to a motor — buy a sheathed multi-core cable instead.

How many single cores can I put in one conduit?

There is no fixed count. Two limits bite: conduit fill, and the grouping factor that derates every circuit sharing the pipe. The more loaded circuits in one conduit, the less current each is allowed. Take the grouping factor for your case from BS 7671, and leave the pipe with room to pull a replacement later.

Does a 4 core cable carry less current than a 2 core of the same size?

Yes, when all the cores are loaded. At 4 mm² it is 36 A against 32 A, a loss of 11.1%; at 25 mm² it is 112 A against 96 A, a loss of 14.3%. Both figures are method C at 30°C. An earth core does not count as loaded, so a 3-core feeding a single-phase point still reads on the two-conductor column.

Which is cheaper, single core or multi core?

The copper is the same either way, so the difference is the sheath and the laying-up: multi-core costs more per metre than the same conductor area in loose single cores. But a 3-core is one pull instead of three, and the labour usually swallows the difference. Ask us for both on the same size and compare the delivered figure.

Single cores or sheathed cable, at the factory rate

Send the size, the core count and the metres with your city. We draw the copper in Lahore and quote at the day's rate — Punjab in 1–2 days, the rest of Pakistan in 2–4.

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