A busbar is a solid, fixed, noninsulated contact point […]
A busbar is a solid, fixed, noninsulated contact point that wires can be attached to with various types of electrically conductive clamps.
It is a rigid piece of copper (or aluminum) that is to be bolted in place. A wire is flexible stranded copper (or aluminum) covered with insulation, that is free to move.
Busbars are better for very high currents. What the crossover current is between the two, is determined by your local wiring code.
Copper busbar is a metallic strip or bar, typically housed inside switchgear, panel boards, and busway enclosures for local high current power distribution. They are also used to connect high voltage equipment at electrical switchyards, and low voltage equipment in battery banks.