How to Install Electrical Wiring in Old Houses

Installing new electrical wiring in an old house can seem daunting, but with proper planning and by following safety guidelines, it can be done safely and efficiently. Here is a step-by-step guide on how to install electrical wiring in an old house:

Safety First

• Turn off the main power at the breaker box before starting any electrical work. Verify power is off by testing outlets with a plug-in tester or voltmeter.
• Wear protective gear like safety goggles, gloves, and long sleeves. Be sure to use insulated tools designed for electrical work.
• Never work on live wires. De-energize wires by turning off relevant breakers.
• Beware of old, brittle wiring that can crack and expose live conductors when disturbed.

Planning The New Wiring

• Examine the existing wiring to see if it can be reused or salvaged. Very old wiring may need complete replacement.
• Decide what additional circuits are needed - for lighting, appliances, home office, etc. Get professional advice if unsure.
• Choose the wire size based on expected electrical load for each new circuit. For most 15A household circuits, #14 AWG copper wire is suitable.
• Develop a wiring diagram to plan wire routing from the breaker panel to endpoints and switches.

Running New Wiring

• Carefully examine walls, floors and ceilings to determine best wiring routes. Avoid plumbing, vents, chimneys, etc.
• Fish wires through finished walls/ceilings from access points like attics or basements. Use long flexible drill bits to make holes.
• For open walls/ceilings, staple cables directly to exposed studs/joists every 4-5 feet.
• Use metal conduit for exposed outdoor wiring runs. Conduit protects cables from damage.
• Label both ends of each wire run for easy identification at the breaker panel.

Breaker Panel And Junction Boxes

• Shut off the main breaker and verify power is off before working on the breaker panel.
• Install appropriate amperage breakers for each new circuit. Follow manufacturer's instructions.
• Connect wire ends securely to breakers, neutral bus bar, and ground bus bar. Double check connections.
• Install new electrical boxes if existing ones cannot accommodate new wiring. Anchor boxes securely.
• Use correct wire nuts/connectors to join wires in boxes. Follow color coding standards.

Testing The New Wiring

• With all wiring complete, turn the main breaker back on but leave new breakers off.
• At each endpoint, use a multimeter to check for power with new breaker still off. Verify wires are not shorted.
• Turn new breakers on one at a time. Walk through the house testing each outlet/light to confirm proper wiring.
• Fix any dead outlets/lights immediately. Double check affected wire runs and connections.
• Once all tests pass, install switches, outlets, light fixtures and other devices as needed.

Stay patient, work methodically, and follow safety procedures when installing new wiring. Seek permits and have work inspected if required by local codes. Done properly, rewiring an old house can upgrade it for modern electrical needs and usage.