A busbar (often pronounced "buzz bar") refers in electrical power distribution to thick strips of Copper or other material that conduct electricity around a switchboard or distribution board.

The size of the busbar determines the maximum amount of current that can be safely carried. Small distribution boards or consumer units may have busbars which have a cross sectional area of as little as 10 mm² but large electrical substations may use metal tubes of 50mm or more in diameter as busbars.

Busbars may be used to carry phase (line, hot, live) voltage in which case they must be suitably insulated. Such insulation may either completely surround the busbar, or alternatively the busbar itself may be uninsulated but physically mounted using an insulating material to keep it electrically separate from its support. Neutral busbars are also insulated. Earth busbars are typically bolted directly onto any metal chassis of their enclosure.

In computers the "Computer bus" allows the flow of electronic signals between components on the circuit boards.