Resistance decides voltage drop, and outer diameter decides how many wires fit in a conduit. This chart collects both for the Class 5 flexible conductors used across the APAR house-wire range, from 0.5 to 16 sq mm, using the values printed on the product pages.
| Size (sq mm) | Strands (No./mm) | Outer diameter range across products (mm) | Resistance (ohm per km) | Drop per amp per metre of route, out and back (mV) |
|---|---|---|---|---|
| 0.5 | 16/0.2 | 2.10 to 2.2 | 39 | 78.0 |
| 0.75 | 24/0.2 | 2.20 to 2.4 | 26 | 52.0 |
| 1.0 | 32/0.2 | 2.40 to 2.70 | 19.5 | 39.0 |
| 1.5 | 30/0.25 | 2.70 to 3.00 | 13.3 | 26.6 |
| 2.5 | 50/0.25 | 3.40 to 3.60 | 7.98 | 16.0 |
| 4 | 56/0.3 | 4.00 to 4.10 | 4.95 | 9.9 |
| 6 | 84/0.3 | 4.50 to 4.70 | 3.3 | 6.6 |
| 10 | 80/0.4 | 6.1 to 6.3 | 1.91 | 3.8 |
| 16 | 126/0.4 | 7.25 to 7.3 | 1.21 | 2.4 |
The strand construction is from the Shakti FR-LSH table. Outer diameter varies slightly between products at the same size, so the range across the six product pages is shown. Resistance is as published and is the same across products for each Class 5 size. The last column is twice the resistance value, which is the drop in millivolts per amp for each metre of route on a single-phase two-wire circuit.
Class 2 conductors
Anushakti HR-FR-LSH is also listed with Class 2 conductors, which have fewer and thicker strands and a slightly larger outer diameter at some sizes.
| Size (sq mm) | Class 2 construction (No./mm) | Resistance (ohm per km) |
|---|---|---|
| 1.0 | 7/0.43 | 18.1 |
| 1.5 | 7/0.53 | 12.1 |
| 2.5 | 7/0.67 | 7.41 |
| 4 | 7/0.85 | 4.61 |
| 6 | 7/1.04 | 3.08 |
Worked example
A 2.5 sq mm circuit carries 10 A over a run of 20 m. The route out and back is 40 m, so the loop resistance is 7.98 ohm per km multiplied by 0.040 km, which is 0.319 ohm. The drop is 10 A multiplied by 0.319 ohm, or about 3.2 V. On a 230 V supply that is about 1.4%.
Assumptions: single-phase two-wire circuit, resistance at the published value, load current constant, no allowance for conductor heating or power factor. A conductor that is warm in service has a higher resistance, so the real drop is somewhat larger. For tabulated drops by cable type see the cable voltage drop table, and for current ratings see the house-wire current rating chart.
Source: APAR product pages, November 2026. The datasheet governs if it differs.