Explain: why is the potential equal at both ends of a wire connection in a circuit?

Explain: why is the potential equal at both ends of a wire connection in a circuit?

In circuit theory, the wire is considered to have no resistance. According to u = IR, r = 0, then I is any value and u is 0
Therefore, there is no potential difference (△ u = 0) at both ends of the conductor, and the potential is equal
In fact, there is resistance in the wire, but it is relatively small. Therefore, when doing some specific analysis, we can not think that the potential at both ends of the wire is equal, so we should analyze specific problems

In any part of a circuit, if the potential at both ends of the wire without electrical appliances is equal, then the potential difference is 0, that is, the voltage is 0, then why is there any difference
electric current,

This is not an absolute zero, but an ideal state. It is usually used in circuit analysis
Voltage = current * resistance, assuming that the resistance is 0 (the resistance of an ideal wire is 0), no matter how large the current is, for example, 10a
So, voltage = current * resistance = 10 * 0 = 0
That is, the voltage is still 0
This is the ideal state