Introduction
Replacing electrical panels in commercial buildings is an important task that requires proper planning and execution. As a beginner, there are key things you need to understand before taking on this project. In this comprehensive guide, I will walk you through the entire process step-by-step.
Reasons for Replacing Electrical Panels
There are several reasons why you may need to replace electrical panels in a commercial building:
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Upgrading to a larger capacity - As you add more electrical loads, you may need a panel with a higher amperage capacity. This is common when renovating or expanding a space.
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Faulty or damaged equipment - Malfunctioning breakers, corrosion, or physical damage can compromise the safety and reliability of the panel. Replacement is required.
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Age and obsolescence - Older panels may not meet current electrical codes and standards. Replacing them improves safety.
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Rewiring - Major electrical rewiring projects often require an updated panel matched to the new wiring.
Choosing the New Electrical Panel
Selecting the right commercial electrical panel is important for performance and safety. Here are key factors to consider:
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Electrical load - Estimate the total amperage or wattage needed currently and for future expansion. This determines the panel capacity.
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Voltage and phase - Match the voltage (120/240V, 208V, 480V) and 3-phase or single-phase wiring.
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Circuit breaker types - Select breakers matched to the electrical system, e.g. HACR for HVAC equipment.
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Enclosure type - Indoor panels may need a NEMA 1 enclosure. Outdoor/wet areas require NEMA 3R.
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Interrupting capacity - Ensure the panel can safely handle short circuit currents based on the utility transformer.
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Extra spaces - Allow room for adding more circuits later. Get a panel with 20-40% spaces above current needs.
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Design and features - Compare design, ease of installation, aesthetics, and added features between models.
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Budget - Get quotes from electrical suppliers to find a top quality panel within your project budget.
Electrical Permits and Inspection
Replacing a commercial electrical panel requires both permits and inspections:
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Electrical permit - Obtain it from your local building department before starting work. Submit panel specifications and electrical load calculations.
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Licensed electrical contractor - In most areas only licensed electricians can get the permit and complete the installation.
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Inspections - An inspector will visit to check wiring connections, grounding, and adherence to electrical code. This is scheduled after installation.
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Certificate of inspection - The inspector issues a certificate if the panel replacement passes inspection. Submit this to the building department.
Scheduling and Safety Planning
Careful planning is necessary before panel replacement:
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Tenant/occupant notices - Inform all affected about the electrical shutdown if power must be turned off.
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Equipment shutdowns - Coordinate with building maintenance to shut down equipment like HVAC safely.
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Emergency lighting - Provide temporary lighting along exit routes. Uninterruptible power supplies may be needed for some equipment.
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Security and access - If power is cut, ensure measures are in place like special keycard access.
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Scheduling electrician - Book a qualified electrical contractor in advance and coordinate a timeframe.
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Materials/equipment - Electrician will supply the new panel but may need access to pathways, conduit, wiring, and meter room.
Step-by-Step Installation Process
The electrical panel replacement process involves carefully planned steps:
Power Disconnection
The utility or on-site power source must be completely disconnected:
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Shut down main breaker and/or utility-side disconnect switch. Use lockout/tagout procedures.
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Test panel and circuits with a non-contact voltage tester to verify power is off.
Removal of Old Panel
With power disconnected, the old panel can be taken out:
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Remove panel cover and label all circuit wires.
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Disconnect wires from breakers and neutral bus bar. Remove ground wires.
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Unmount the panel and remove it from the wall.
Installation of New Panel
The new commercial panel can now be installed:
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Mount the new panel securely in place on the wall. Allow proper work space clearance.
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Anchor the panel to wall framing using manufacturer's instructions.
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Connect the grounding electrode conductor to the ground bus bar.
Circuit Wiring
The existing branch circuit wiring is reconnected:
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Match each circuit wire label and reconnect to new breakers. Follow wire sizes required by the breaker.
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Connect neutral wires to the neutral bus bar. Double check connections are tight.
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Connect ground wires to ground bar.
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Ensure proper wire arrangement for panel ventilation and clearance.
Inspection and Power Restoration
The final steps complete the installation:
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Schedule inspection by the electrical authority having jurisdiction.
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Address any issues noted by inspector and schedule a re-inspection if needed.
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Once approved, restore power from utility or on-site source and test operation.
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Install front panel cover to complete the installation.
Ensuring Electrical Panel Safety
It is critical to follow all safety measures, including:
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Use personal protective equipment like insulated gloves and wear arc flash clothing for protection.
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Never work on an energized panel. Follow full lockout/tagout procedures before starting work.
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Double check wires are connected to the correct breaker, fully inserted, and tightened properly.
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Ensure the panel and breakers are properly rated and listed for commercial use.
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Only qualified electricians should install panels to ensure proper techniques and electrical code compliance.
Conclusion
While replacing commercial electrical panels requires careful planning and execution, this guide provides a step-by-step overview of the complete process to help beginners fully understand proper installation. Paying attention to safety, using qualified electricians, and following regulations will ensure your new electrical panel upgrade is completed successfully.