Why does the breaker kick off when the positive wire touch the negative wire?

Answer 1

In every electrical circuit there has to be a resistive or inductive load that limits the current inrush to that of the devices internal resistance. Without that resistance in the circuit, the current will not be restricted and will go to a very high value instantaneously.

In the electrical trade this is known as a short circuit. At this very high current value that are only two ways that the current flow will stop. One is the circuits's overload protection, usually a breaker or fuse, will trip and that will open the circuit. The second is that the wires that have become shorted will generate so much heat that the wires will burn and melt open. Once that happens the current flow will stop.

Answer 2

When the positive and negative wires touch, it creates a short circuit by completing a direct path for electricity to flow. This sudden surge of current overload the circuit, causing the breaker to trip in order to prevent potential damage or fire hazard. The breaker's job is to interrupt the flow of electricity when it reaches a dangerous level.

Answer 3

because you are shorting the loop

Answer 4

Dead short.