Question

WHY DOES AN ELECTRICIAN WEAR RUBBER GLOVES WHEN HE WORKS?

Answer 1

because rubber is an insulator ie electricity does not pass through the gloves which further would pass into the the electrician's body
It prevents the person to get a shock

Answer 2

Why does an electrician wear a rubber gloves when he works?

Rubber is an insulator which doesn't allow electric current to pass through it.

So, if by chance the electrician wearing rubber gloves or shoes happens to touch a live wire, the rubber gloves will not allow the current to pass through his body to the earth.