If we were going to describe the relationship between current, voltage, and power, you could say:

You cannot have power without voltage.

The equation is: Power = voltage times current.

If either voltage is zero or current is zero, there is no power.

Ohm’s Law: Voltage = Current times resistance is also closely related.

If there is zero resistance, power is also zero

r=rho l/a where a is the area, l is the length and rho is resistivity so the greater the area the lesser the resistance thats why the earth pin is thicker bcos current follow the shortest path, so less resistive .