Choosing the correct electrical panel type is essential for safety, code compliance, and system performance. One of the most common decisions contractors and engineers face is selecting between a Main Lug Only (MLO) panel and a Main Circuit Breaker (MCB) panel.
While both serve important roles in electrical distribution, they are designed for different applications. Understanding the difference helps prevent costly mistakes and inspection issues.
What Is a Main Lug Only (MLO) Panel?
A Main Lug Only panel does not include a main disconnect breaker. Power is supplied directly to the lugs, and the disconnect is typically located upstream.
Common Uses for MLO Panels
- Sub‑panels fed from a main service panel
- Systems where a disconnect already exists
- Applications requiring centralized shutdown control
Advantages of MLO Panels
- Cost‑effective for sub‑panel installations
- Flexible for system expansions
- Ideal when a main disconnect is not required at the panel
MLO panels are commonly used in commercial and industrial environments where power control is managed elsewhere in the system.
What Is a Main Breaker (MCB) Panel?
A Main Breaker panel includes a built‑in main circuit breaker that allows power to be shut off directly at the panel.
Common Uses for MCB Panels
- Service entrance applications
- Panels requiring an on‑site disconnect
- Locations where code requires local shutoff
Advantages of MCB Panels
- Provides immediate power shutdown at the panel
- Enhances safety during maintenance
- Simplifies code compliance in many jurisdictions
MCB panels are often required where the panel serves as the primary distribution point.
Key Differences at a Glance
| Feature | Main Lug Panel | Main Breaker Panel |
|---|---|---|
| Main Disconnect | No | Yes |
| Typical Use | Sub‑panel | Service entrance |
| Cost | Lower | Higher |
| Safety Control | Upstream | At panel |
| Code Requirements | Location‑dependent | Often required |
Which Panel Is Right for Your Project?
The correct choice depends on several factors:
- Local electrical codes
- System design
- Location of disconnects
- Safety and maintenance needs
Choosing the wrong panel type can lead to inspection failures or costly redesigns. That’s why panel selection should always be verified before production.
How Electrical Panelsfast Helps
At Electrical Panelsfast, we review your drawings and specifications to ensure:
- The correct panel type is selected
- Code considerations are addressed
- Layout and breaker configurations are accurate
Every panel is built to match approved requirements—no assumptions, no shortcuts.
Built for Accuracy and Reliability
Whether you need a Main Lug or Main Breaker panel, our builds include:
- Genuine brand components
- Accurate labeling
- Torque‑checked connections
- Quality control documentation
Panels are delivered fully assembled and ready to install.
Conclusion
Main Lug and Main Breaker panels serve different purposes, and selecting the right one is critical for safety and compliance. Understanding how each functions helps ensure your project stays on schedule and passes inspection without issues.
Need Help Choosing the Right Panel?
Send us your project details or upload your one‑line diagram. Our team will help you select the correct configuration and deliver a fast, accurate quote.
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