There are 3 factors affecting the resistance of an electrical cable.
- The material from which it is made. This is called the RESISTIVITY. Gold has a particularly low resistivity but the cheapest alternative is copper.
- The LENGTH of the cable. If you double the length, there is twice as much resistance. That's because electrons experience resistance when they crash into metal atoms. Double the length means twice as many atoms to hit.
- The CROSS-SECTIONAL AREA of the wire. The wider the wire, the more space there is. More electrons can be sent down at once so the current is higher and we therefore say that the resistance is lower. Double the cross-sectional area means you halve the resistance.
So you really want short, wide copper wires.
