Why electrical workers use rubber shoes and thick cloth/rubber gloves? In addition, they usually use one hand and the other hand is in their pocket, why so?

Electrical workers are at a risk of getting electric shock. To avoid this danger, it is advisable that they wear rubber-soled shoes. Rubber is an insulator - this insulates the worker from the ground potential. So if they touch a live wire while working, they will remain at the live wire's potential and not be at a different potential. Were it not for this protection, there is a risk of them being at a ground potential and then touching a live wire - resulting in a current path through their body. If the current is large, it also could be life threatening.

To prevent an electric shock, in addition to the rubber-soled shoes, they also wear thick cloth or rubber gloves. This is a double precaution for them.

A large current through one's body interferes with the heart's functioning, which is undesirable. Electrical workers are therefore advised to keep their one hand, especially the left hand in their pocket. In case the worker touches a live wire with his right hand, the current path will be from the right hand through the body towards his right leg and then to the ground. The current will not pass through the heart, which is towards his left arm. This procedure is taken again as a precaution and for the safety of the worker.