How to Rewire Your Entire Office Building Without an Electrician

Introduction

Rewiring an entire office building is a complex project that requires careful planning and execution. While it's recommended to hire a licensed electrician, it is possible for a dedicated DIYer to complete the rewiring themselves if they have the necessary electrical skills and experience. This guide will walk you through the key steps and considerations for rewiring an office building from start to finish without an electrician.

Assessing the Existing Electrical System

Before beginning any rewiring work, you need to thoroughly assess the existing electrical system in the building. This involves:

Evaluating the Electrical Panel

• Examine the main electrical panel and all subpanels, looking for problems like corrosion, damaged breakers, insufficient amperage capacity, etc.

• Verify that the electrical panels are sufficiently rated for the building's power needs. Panel upgrades may be necessary.

Mapping Out All Circuits

• Identify where all the wiring and components are located.

• Label each circuit at the breaker.

• Draw up detailed circuit maps showing all outlets, switches, lighting fixtures, appliances, etc.

Inspecting All Electrical Components

• Check all outlets, switches, junction boxes, wiring, etc. for damage, improper installations, hazardous materials like knob-and-tube wiring or aluminum wiring, etc.

• Use a voltage tester to check for faulty wiring.

• Replace any damaged or dangerous components.

Load Testing Circuits

• Turn on all lights and appliances to test each circuit under a real load.

• Check for tripped breakers, overheating wires, lights dimming, etc.

Planning the New Wiring Layout

Once you have a complete understanding of the existing system, the next key step is planning out the new wiring layout.

Choose a Wiring Method

• Romex NM cable is the most common wiring method for office buildings. It's versatile, inexpensive, and easy to install.

• Conduit provides the most protection for wiring but requires more labor to install.

• Other options like armored cable, metal clad cable, etc. have pros and cons.

Create Detailed Wiring Diagrams

• Map out where all new wires, circuits, outlets, switches, panels, etc. will be located.

• Plan dedicated circuits for large appliances, HVAC units, electronics, etc.

• Balance electrical load across circuits. Follow all code requirements.

Calculate Electrical Load Needs

• Add up the amperage ratings for all equipment to be wired.

• Confirm the main panel rating can handle the total load. Upgrades may be needed.

• Allow for future expansion needs as well.

Removing Old Wiring

Once the new system is planned out, it's time to remove the old wiring:

Shut Off Main Power

• Turn off the main breaker and all subpanels. Verify power is off with a voltage tester.

Remove Devices from Circuits

• Take outlet and switch covers off. Disconnect all wires and remove the devices.

• Label wires as you disconnect them to aid reinstallation. Cap wires for safety.

Take Out Old Wiring

• Carefully pull wiring out of conduits or extract stapled cables from studs. Watch for hidden junction boxes.

• Completely remove abandoned wiring back to the panel. Don't abandon wires in walls.

• Safely dispose of old wiring according to local regulations.

Installing New Wiring System

Now the fun part - running all the new wires according to your rewiring plan:

Run Cable and Conduit

• Run NM cables through holes drilled in studs per code requirements. Staple neatly at regular intervals.

• Install conduit where needed. Use sweeps for smooth bends.

Mount New Electrical Boxes

• Install properly sized junction, outlet, and switch boxes where required. Follow box fill limits.

• Use nail guards to protect cables from errant nails and screws.

Connect Wires at Panels

• Carefully make tight, high-quality connections at main and subpanels.

• Organize and label wires clearly at panels. Leave extra wire length.

Connect Devices and Fixtures

• Install outlets, switches, lights, appliances per your diagrams using proper connectors.

• Verify ground wires are properly connected. Use GFCI outlets where required.

Testing and Completion

The final critical stage is thoroughly testing and completing the rewiring project:

Inspect Work

• Verify all work complies with electrical code for proper installation practices, wire and box sizing, etc.

Load Test Circuits

• Turn power back on and activate all circuits while watching panels carefully.

• Check for any shorts, loose wires, overloaded circuits, etc. Fix any issues.

Add Finishing Touches

• Install cover plates, conduit boxes, trim pieces, etc for a clean finished look.

• Label all circuits clearly in panels and junction boxes.

• Update electrical drawings with as-built details.

With diligent planning and attention to safety, it is possible for a skilled DIYer to successfully rewire an entire office building. But due to the complexity, it's highly advisable to have professional electricians handle or at least thoroughly inspect the project. Attempting to cut costs by not hiring a pro can endanger your building - and lives.