Wire Material and Resistance Basics (UK)

Overview

Material and resistance decisions are easier when the assumptions are explicit. Keep the workflow metric-first, quantify resistance effects, and document the rationale in UK terms.

Copper vs Aluminium in Practice

Copper typically has lower resistivity than aluminium, so equivalent runs usually show lower resistance at the same cross-sectional area.

Material selection should consider installation context, project constraints, and documentation requirements, not just one numeric property.

Length and Area Are First-Order Drivers

Resistance rises with conductor length and falls with larger conductor cross-sectional area. Long external runs and outbuilding feeds can show this effect quickly.

Converting all source data to mm² before comparison keeps UK design conversations consistent across stakeholders.

Temperature and Power-Loss Interpretation

Resistance estimates are temperature-sensitive. If operating temperature rises, predicted resistance and I²R loss usually rise as well.

Use these calculations for transparent planning and communication, then verify final design choices against current standards and full project conditions.

Try These Tools

• Resistance Calculator UK
• Voltage Drop Calculator UK
• Ampacity Reference UK

References

• Electrical resistivity reference table (General material properties)
• IEC 60228 — Conductors of insulated cables (Metric area framework)
• BS 7671 (IET Wiring Regulations) (UK design context)