Inside every panel and switchgear lineup there is a common conductor that the incoming power lands on and that every outgoing circuit taps from. That conductor is the busbar - a plain but critical piece of metal that carries the full current of the assembly. This guide explains what a busbar is, why a solid bar is used instead of cable, how busbars are rated and arranged, and where they sit in oil and gas power distribution.
Busbar in one line: A busbar is a rigid metallic conductor - usually a bar or strip of copper or aluminum - that carries and distributes electrical power to multiple circuits within switchgear, a panelboard, an MCC, or a distribution board. Incoming power connects to the busbar, and each outgoing circuit taps off it through a breaker or fuse, making the bar a common connection point that carries the combined current.
Where many circuits branch from a single point, running individual cables to a common terminal becomes bulky and impractical. A busbar solves this by acting as a shared, low-resistance backbone: the main supply lands on the bar, and every breaker or feeder taps off it along its length. This is compact, easy to extend, and mechanically robust.
A solid bar also handles high current efficiently. Its large, flat cross-section carries current with low resistance and good heat dissipation, and its shape can be sized for the exact ampacity needed. Because it is rigidly mounted and braced, a busbar also withstands the enormous mechanical forces that fault currents produce - forces that would whip loose cables violently. Three-phase systems use a set of parallel bars, one per phase plus neutral and ground as needed.
A busbar is rated for continuous current (ampacity), which depends on its cross-sectional area, material, plating, and cooling. Copper carries more current per unit area than aluminum but costs more; aluminum is lighter and cheaper and common in larger bars. Just as important is the short-circuit withstand rating - the bar and its bracing must survive the mechanical and thermal stress of a bolted fault until a breaker clears it.
Configurations vary with the reliability required. A single main bus is simplest. A main-tie-main or double-bus arrangement uses two buses joined by a tie breaker, so one bus can be de-energized for maintenance while the other keeps loads energized. Ring buses and sectionalized buses add further flexibility. Busway (bus duct) is an enclosed, prefabricated busbar system used to run high current across a building or between switchgear and transformers.
In oil and gas power distribution, busbars are the internal backbone of switchgear, MCCs, panelboards, and distribution boards throughout a facility - from the medium-voltage bus in the main switchgear down to the low-voltage bus feeding motor starters in an MCC. A well-designed bus scheme, often main-tie-main on critical plants, lets operators maintain one section without dropping the whole facility.
Busbars themselves are passive and carry no intelligence, but the metering and protective relays connected to a bus continuously measure its voltage, current, and power and detect faults. A cloud SCADA such as Merobix can read those bus metering and breaker tags over Modbus or DNP3, so operators see the loading and health of each electrical bus - and any bus fault or tie-breaker operation - across remote sites from one dashboard.
A busbar is a common conductor that distributes incoming power to multiple outgoing circuits inside switchgear, panelboards, and MCCs. The main supply lands on the bar, and each breaker or feeder taps off it. It provides a compact, robust, low-resistance connection point that carries the combined current of all the circuits it serves.
Most busbars are copper or aluminum. Copper carries more current per unit area and has lower resistance, but costs more and is heavier. Aluminum is lighter and cheaper and is common in larger bars. The choice depends on the required ampacity, weight, cost, and connection method for the assembly.
It uses two separate buses connected by a tie breaker, each fed by its own source. Loads are split across the two buses. If one source or bus needs service, its loads can be carried by the other bus through the tie breaker, so maintenance does not drop the whole facility. It is common on critical oil and gas plants.
This page references the protocol specifications published by the organizations below. Editions, product capabilities, and documentation change over time - confirm current requirements and specifications directly with the source.
Last reviewed: July 27, 2026. Merobix is not affiliated with, endorsed by, or sponsored by these organizations; their names are used only to identify the standards and products discussed.
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