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[Beau388]

Originally Posted by frankgtx

The smallest influence comes from the fact that the electrons have to be redirected. As the mean free path of electrons in a wire is of the order of just a few atoms, and the drift speeds more in terms of mm/s, this effect is nearly immeasurable. But the bend will heat up just a little bit more than the rest of the wire.

More severe is that sharply bending a wire will distort the material, inducing stress, and changing grain boundaries, and that will increase the resistance.

Another effect comes from the magnetic field that the current causes. Suppose you make a 180° bend, now currents are flowing opposite to each other. That will lead to a repulsive force between the wires. The electrons as a result will have a lower drift speed, so a higher resistance.

It’s all just miniature effects, but they do exist.

I remember my days in the high power EE lab. Big 1x3" buss bars caring 440 volt 3 phase. The whole world had a 60 cycle buzz when the prof turned the power on.