Why are electric wires insulated?

Answer 1

If you don't have insulation on the wire, then the loops in the coil will touch each other and short to each other. Instead of have x number of turns on the coil, you would basically have a solid conductor if the wire was not insulated.

Answer 2

1. to keep the electricity in
2. to keep other things out (e.g. water, people, other wires)
3. to prevent short circuits to nearby wires
4. to prevent electricution
5. to prevent fires
6. etc.

Answer 3

A transformer is basically a coil of wire (or two coils).

If it were not insulated, the current would bypass the coils and it would not function.

Answer 4

prevent short circuits in the windings