Question

why thick wire is used to connecting wire​

Answer 1

Because it just acts as a normal electric contact in the circuit or wiring. In order to reduce the area and to maintain a minimum resistance to generate heat, fuses are made as thin. A fuse wire should not have high resistance or low resistance. That is the fuse thickness increases with the current rating.

Answer 2

Answer:

Thick wire = low resistance.

Low resistance is the goal, right? So we use thick wires.

The reason is that resistance is inversely proportional to area of c-section. Another way of thinking is that you imagine wire as a tunnel. Now the more emptier i.e bigger the tunnel, more faster more people can move. In the case of wire, in a thick wire more electrons can move easily through it than thin wires.

Thats the answer right there!