A motor control center is the central enclosure that houses and protects the starters, breakers, and controls for a group of electric motors. In an oil and gas facility, one MCC lineup can feed dozens of pumps, compressors, and fans from a single organized assembly. This guide explains what an MCC is, how it is built, and how it ties into a SCADA system.
Motor Control Center (MCC) in one line: A motor control center (MCC) is a floor-standing assembly of vertical sections that houses the combination starters, circuit protection, and control devices for multiple electric motors, distributing power to them from a common bus.
A motor control center is a modular lineup of steel vertical sections bolted side by side, each divided into compartments. A horizontal power bus runs across the top of the lineup and vertical buses drop into each section, so every compartment can tap the same incoming supply. This lets one central assembly power and control an entire area's motors instead of scattering individual starters around the plant.
Each motor gets its own removable compartment, commonly called a bucket. A typical bucket contains a circuit breaker or fused disconnect for short-circuit protection, a contactor to switch the motor on and off, and an overload relay to protect against sustained overcurrent. Buckets are drawer-style and interlocked so a technician cannot open a live compartment, and a faulted bucket can be swapped without de-energizing the whole lineup. Low-voltage MCCs (up to 600 V) are the norm for most oilfield process motors; medium-voltage lineups exist for large compressors.
On a gas plant, compressor station, or saltwater disposal facility, the MCC is the electrical heart of the process area. It feeds the motors that drive injection pumps, transfer pumps, cooling fans, and compressor auxiliaries. Consolidating this gear into one lineup simplifies maintenance, arc-flash management, and the wiring back to the control system.
Modern MCC buckets increasingly include intelligent overload relays and soft starters or variable frequency drives (VFDs) that publish motor current, run status, and fault codes over a fieldbus such as Modbus, EtherNet/IP, or PROFIBUS. A SCADA platform reads those values so operators can see, from a dashboard, which pumps are running, their amperage, and any trip conditions. Merobix ingests MCC and drive data over Modbus or EtherNet/IP where the devices expose it, giving remote visibility into motor health without adding hardware to the lineup.
Switchgear is built to distribute and protect main power circuits at higher fault ratings and typically feeds large loads, transformers, and other panels. An MCC is optimized for controlling many individual motors, packing dozens of starters into compartmentalized buckets. Switchgear distributes power upstream; the MCC controls motors downstream.
A standard combination starter bucket contains a disconnect (circuit breaker or fused switch), a contactor that opens and closes the motor circuit, and an overload relay that trips on sustained overcurrent. Buckets may also hold control transformers, VFDs, soft starters, and terminal blocks for control wiring.
Yes, if the MCC uses intelligent starters, smart overload relays, or drives with communication ports. These devices publish current, run state, and fault data over Modbus, EtherNet/IP, or PROFIBUS, which SCADA can poll. Older electromechanical buckets provide only hardwired run and trip contacts that must be brought into a PLC or RTU.
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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