How to Rewire Your Entire Office Building Without Hiring an Electrician

Understanding the Electrical System

Before attempting to rewire an office building, it is crucial to understand the electrical system and components involved. This includes:

• Service panel - The main service panel connects the building to the utility power lines and distributes electricity throughout the circuits. This contains the main circuit breakers or fuses.

• Breaker box - Most office buildings have multiple breaker boxes that connect to the main service panel. These house the circuit breakers for each office or area.

• Wiring - The building wiring runs from the service panel through walls, ceilings, and conduits to distribute power. This includes:

  • Phase wiring - Carries the main 120V or 240V power.

  • Neutral wires - Completes the circuit back to the service panel.

  • Ground wires - Provides a safe path for fault currents.

• Receptacles & switches - Wall outlets and switches connect to the building wiring system.

• Fixtures - Light fixtures, motors, HVAC systems, and other hardwired equipment get power from the building wiring.

Understanding how these components connect and work together is essential for a DIY rewiring project. Examining the existing wiring diagram and layout before starting is highly recommended.

Gathering the Required Materials

Rewiring an office building is a large project that requires a significant amount of electrical supplies and materials. Here are some of the key items needed:

• Wire - Different gauge sizes are needed for the main feeds, branch circuits, and ground wires. This includes nonmetallic sheathed cable, individual THHN/THWN-2 conductors, etc.

• Conduit - EMT metal conduit or PVC/liquidtight flexible conduit for protecting feeder wires and branch circuit runs.

• Circuit breakers - New circuit breakers matched to the rewiring, potentially a new main breaker.

• Receptacles & switches - New devices that match the building's circuit count and layout.

• Junction boxes - For housing wire connections and branching the circuits.

• Cable staples & tie wraps - For securing cables alongceilings and walls.

• Fish tape/pull cords - For pulling wires through walls and conduit runs.

• Cable strippers, crimpers & testers - Tools for safely installing new electrical wiring.

• Labels - For clearly identifying all wires, breakers, junction boxes, and connections.

• Safety gear - Including gloves, glasses, boots, hard hat, and arc flash protective equipment.

Take inventory of all required materials before starting the rewiring project. Having everything on hand will make the installation process go smoother.

Step-by-Step Rewiring Process

With the necessary materials and good understanding of the electrical system, the office can be rewired using the following general steps:

1. Turn Off Main Power and Inspect Electrical Components

The first step is to turn off the main breaker at the service panel, then verify power is off everywhere using a non-contact voltage tester. Thoroughly inspect all existing wiring, boxes, and devices throughout the building to develop a rewiring plan. Look for any damaged equipment or hazardous wiring that needs replacement.

2. Remove Existing Wires, Receptacles & Switches

Next, start stripping out all of the old electrical wires and cables from the walls, conduits, and ceilings. Remove old wiring back to the junction boxes. Take out all switches, receptacles, fixtures, and equipment as well.

3. Install New Electrical Boxes

With the old wiring removed, upgrade any outdated electrical boxes and add new junction boxes where needed according to code. Run new conduit between locations.

4. Pull New Wires & Cables

Now the new wires can be pulled between the boxes and back to the panels. Use cable lubricant and fish tape to pull wires through walls and conduit. Observe box fill capacity and wire derating when running multiple wires.

5. Connect Wires and Devices

Carefully connect the new wires to all devices and boxes using the specified termination methods (pigtailing, wire nuts, etc). Apply wire labels at both ends for identification.

6. Mount New Receptacles, Switches & Equipment

With the wiring completed, install all new switches, receptacles, junction covers, and electrical equipment such as lights. Follow manufacturer instructions carefully.

7. Inspect, Test & Troubleshoot Wiring

Before turning the power back on, thoroughly inspect the new wiring installations and connections. Check for secure connections, proper wire stripping, grounding, and no shorts between wires. Verifying correct circuit polarity and using a multimeter to test for continuity can find issues.

8. Energize Panels and Verify Proper Operation

Once wiring passes inspection, turn the main power back on. Then systematically turn on each circuit to verify proper operation of all equipment. Check for any hot spots or tripped breakers. Diagnose and fix any identified problems.

Following Safety Protocols

Working on electrical wiring is extremely dangerous if proper precautions are not taken. Be sure to follow these safety protocols throughout the rewiring process:

• Keep the power off and use lockout/tagout procedures when working on wiring and connections.

• Wear insulated gloves rated for the voltage as well as safety glasses/goggles when handling wires.

• Frequently test wires to confirm they are de-energized before touching.

• Use insulated tools and equipment designed for electrical work.

• Allow only qualified electricians to handle the service panel and high-voltage connections.

• Keep the area clear with safe access to electrical components.

• Never work on wiring that appears damaged or substandard.

Strictly adhering to electrical safety procedures reduces the risk of shock, arc flash burns, electrocution, and fire. Stay diligent when working around energized electrical systems.

Final Verification and Inspection

Upon project completion, the local permitting office will need to be contacted to perform a final inspection and approve the rewiring work done before the building can be officially re-occupied. The inspector will:

• Check that all electrical components are properly sized and installed according to code.

• Verify the condition and tension of all wiring connections.

• Confirm appropriate circuit labeling and breaks.

• Test operation of switches, receptacles, lights, and equipment.

• Evaluate general workmanship, insulation, and safe clearances.

Address any final corrections or issues identified by the inspector. Once approved, obtain a signed final inspection certificate and building re-occupancy permit.

By methodically following the proper rewiring steps and safety protocols, an office building can be successfully rewired without the expense of hiring an electrician. Just be sure to research local permitting requirements and obtain all necessary licenses and inspections. Stay safe!