When designing an industrial power distribution system, one of the most common questions engineers face is: Should I specify a Motor Control Center (MCC) or a Power Control Center (PCC)?
While both are types of low voltage switchgear, they serve fundamentally different purposes. Choosing the wrong assembly can lead to oversized equipment, inadequate protection, or unnecessary costs. This guide provides a definitive technical comparison to help you make the right decision.
What Is a Motor Control Center (MCC)?
A Motor Control Center (MCC) is an assembly of one or more enclosed sections having a common power bus and containing principally motor control units. MCCs centralize the control and protection of multiple electric motors in a single location.
According to NEMA ICS 2 and IEC 61439-2, MCCs are designed for:
- Motor starter units (direct-on-line, star-delta, soft starters, VFDs)
- Circuit breakers or fuses for motor branch circuit protection
- Control devices (pushbuttons, indicator lights, PLCs)
- Metering and communication modules
Typical MCC Applications
- Manufacturing plants with conveyor systems, pumps, and compressors
- Water and wastewater treatment facilities
- HVAC systems in commercial buildings
- Oil and gas processing plants
For more details on LV switchgear types, see our complete guide to low voltage switchgear.
What Is a Power Control Center (PCC)?
A Power Control Center (PCC) is a type of low voltage switchgear designed to receive power from transformers or generators and distribute it to downstream loads such as MCCs, distribution boards, and large individual loads.
PCCs are characterized by:
- Higher current ratings (typically 1,600 A to 6,300 A)
- Higher short-circuit withstand capacity
- Larger circuit breakers (Air Circuit Breakers – ACBs)
- Bus couplers for dual-source or transfer schemes
- Advanced protection relays and metering
Typical PCC Applications
- Main distribution in industrial plants
- Data center power distribution
- Hospital main switchboards
- Commercial building main distribution
MCC vs PCC: Side-by-Side Technical Comparison
| Parameter | Motor Control Center (MCC) | Power Control Center (PCC) |
|---|---|---|
| Primary function | Motor control and protection | Power distribution and protection |
| Rated current | Up to 1,000 A (typical: 100-630 A) | 1,600 A to 6,300 A |
| Main breaker type | MCCB or MPCB | ACB (Air Circuit Breaker) |
| Short-circuit capacity | Up to 50-65 kA | Up to 100 kA |
| Typical voltage | 400/415 V AC, 480 V AC | 400/415 V AC, 690 V AC |
| Withdrawable units | Common (for motor starters) | Less common (fixed ACBs typical) |
| Busbar rating | Up to 1,600 A | Up to 6,300 A |
| Metering | Motor-specific (current, run hours) | System-level (power, energy, harmonics) |
| Communication | Modbus, Profibus, Ethernet/IP | IEC 61850, Modbus TCP, DNP3 |
| Physical size | Compact, modular | Larger, heavier |
| Form of separation | Form 2b to Form 4 | Form 2b to Form 4 |
| IEC standard | IEC 61439-1, IEC 61439-2 | IEC 61439-1, IEC 61439-2 |
How MCCs and PCCs Work Together in a Power Distribution Hierarchy
In a typical industrial power distribution system, the hierarchy flows as follows:
- Utility transformer or generator → feeds the PCC
- PCC (main distribution) → distributes power to MCCs and large loads
- MCC (motor control) → controls and protects individual motors
- Distribution boards → feed lighting, outlets, and small loads
This hierarchical structure ensures selective coordination—when a fault occurs at a motor, only the motor’s protective device operates, leaving the rest of the plant energized. The PCC provides the upstream protection and isolation point for the MCC.
Key Selection Criteria: When to Choose MCC vs PCC
Choose an MCC When:
- You have multiple motors (typically 5 or more) in a localized area
- Motor ratings are below 200 kW (typical LV motor range)
- You need motor-specific protection (overload, phase loss, stall)
- You want to centralize control (start/stop from a single location)
- Space is limited and modular, compact design is preferred
- You require VFD or soft starter integration
Choose a PCC When:
- You need a main distribution point for the facility
- The incoming transformer rating exceeds 1,000 kVA
- You need to distribute power to multiple MCCs and sub-panels
- The system requires bus couplers for dual-source redundancy
- You need high short-circuit withstand (>65 kA)
- You require advanced power monitoring (energy management, power quality)
MCC vs PCC: Cost Comparison
Cost is always a factor in equipment selection. Here’s a general cost framework:
| Component | MCC Cost Range | PCC Cost Range |
|---|---|---|
| Enclosure and busbars | $3,000 – $8,000 per section | $10,000 – $30,000 per section |
| Main breaker | $500 – $2,000 (MCCB) | $5,000 – $15,000 (ACB) |
| Motor starter unit | $800 – $3,000 per unit | N/A |
| Protection relay | $200 – $800 | $1,000 – $5,000 |
| Metering | $300 – $1,000 | $2,000 – $8,000 |
Note: Costs are indicative and vary by manufacturer, region, and specifications. Contact SwitchGearMFG for a detailed quotation.
Common Mistakes When Specifying MCCs and PCCs
Mistake 1: Using a PCC Where an MCC Is Needed
Some engineers specify a PCC with individual motor breakers instead of an MCC to save cost. This approach often backfires because:
- Motor protection requires specific relay curves (Class 10, 20, 30) that standard ACBs do not provide
- Control wiring becomes complex and error-prone
- Lack of withdrawable units makes motor starter replacement difficult
Mistake 2: Undersizing the PCC Busbars
The PCC busbar rating must accommodate not only the present load but also future expansion and inrush currents from motor starting. A common rule of thumb is to size the PCC busbars at 125% of the calculated maximum demand.
Mistake 3: Ignoring Selective Coordination
When a motor fault occurs, only the MCC motor starter should trip—not the PCC feeder breaker or the main breaker. This requires careful coordination of protection curves between:
- Motor overload relays (Class 10/20/30)
- MCCB magnetic trips in the MCC
- ACB short-time delay settings in the PCC
The IEEE 242 (Buff Book) provides detailed guidance on protective device coordination.
Standards and Certifications for MCCs and PCCs
Both MCCs and PCCs must comply with applicable standards:
- IEC 61439-1 and IEC 61439-2: General rules and power switchgear assemblies
- UL 845: U.S. standard for motor control centers
- UL 1558: U.S. standard for metal-enclosed low voltage power circuit breaker switchgear (PCC)
- NEMA ICS 2: Industrial control and systems: controllers, contactors, and overload relays
- IEC 60947: Low voltage switchgear and controlgear components
Always verify that your supplier provides type test certificates for:
- Temperature-rise testing
- Short-circuit withstand testing
- IP verification (for the specified environment)
- Internal arc containment (if required)
Can MCC and PCC Be Combined?
Yes. In smaller facilities or where space is constrained, combination units are available that integrate PCC and MCC functions in a single assembly. These are often called Main-Tie-Main (MTM) configurations or integrated power centers.
However, combining functions reduces flexibility and can complicate maintenance. For facilities with more than 10 motors or complex power distribution requirements, separate MCC and PCC assemblies are recommended.
Conclusion
MCCs and PCCs are complementary, not competing, technologies. The MCC focuses on motor control and protection, while the PCC manages main power distribution. Understanding their differences ensures correct specification, proper selective coordination, and optimal lifecycle cost.
At SwitchGearMFG, we manufacture both low voltage MCCs and PCCs in compliance with IEC 61439, UL 845, and UL 1558. Our engineering team can help you design a power distribution architecture that matches your load profile, protection requirements, and budget.
Contact us today for a free design consultation and quotation.