why do current-carrying wires have multiple thin copper wires instead of a single thick copper wire?

Question

In domestic current-carrying wires, there are many thin copper wires inside the plastic insulation. Why is that so? Why can’t there be a single thick copper wire carrying the current instead of so many thin ones?

In: Engineering

Answer 1

The reason is,

if you take a big piece of metal, and you bend it, the outside is longer than the inside, which is stressful to the metal. That makes it harder to do the bend, and it produces wear and tear.

By contrast, if you take a bunch of parallel strands, this isn’t as much of an issue since the strands can just slide next to each other.

Now, I will note that some wires (particularly ones that don’t expect to be bent very often, like the wiring of a house) do use a single, thick piece of metal.