How to Wire the Electricity in an Old House
- 1). Check local building code requirements for household wiring, usually with a municipal bureau of licenses and inspections. Homes built since the 1940s may have intact electrical systems, but they probably do not carry the capacity for modern appliances and electronics. The highest level of safety would dictate having a licensed electrician conduct a thorough inspection of the existing wiring system to uncover unsafe conditions or code violations.
- 2). Inspect the service entry, which consists of the wire and connections coming from the street. Most service today is 100 amperes, or amps, but older homes may have only 60-amp or even 30-amp service. Amperage rating can be determined from the markings on the conductor cable coming into the panel board. Upgrade service if necessary. Check voltage level to determine whether 240-volt service is provided, which would show a three-wire connection connected to the house, 120-volt only two wires. Many large appliances need 240-volt service. Check with service provider to make sure appropriate service is available before making changes. Do a visual inspection to make sure service wire does not touch trees or structures. Overhead wires must be at least 10 feet off the ground, and cannot be reachable through a window or other accessible openings. Any changes to the service entry cable must be made by a licensed electrician.
- 3). Replace panel board, also known as the circuit breaker box or fuse box, with a modern device if necessary. The panel board distributes electricity throughout the house and protects wiring from power overloads. Most older panels are not grounded and should be replaced with grounded panels. The panel must match the amperage and voltage ratings coming into the house. Check to make sure panel board will hold the number of branch circuits planned. Label all circuits before dismantling the old panel board. Disconnect all service leads coming into the panel. Remove the panel box from the wall and inspect for rust or water damage. Move panel board location if any signs of water damage appear. Mount new panel board, then connect to ground wire. Connect service leads to new panel.
- 4). Connect the panel to a proper ground using an 8-gauge bare copper wire. A proper ground could be any of the following: Copper rod sunk into the earth, a metal water pipe entering the building from outside, or the metal casing of a well.
- 5). Replace and add branch circuits from the panel board throughout the house. Branch circuits distribute electricity from the panel board throughout the home. Most local codes require grounded electrical systems. Grounded wire consists of three wires: one black "hot" wire, one white "neutral" wire and a ground wire that is usually uncoated. Homes built before the 1980s probably will not be grounded correctly. If this is the case, and if wiring is otherwise sub-par or made of aluminum, replace all wiring. When replacing an existing circuit, the old wire may be connected to the new wiring to pull it through walls and ceilings. When placing new outlet or switch locations on a circuit, holes must be cut in walls and ceilings with a reciprocating saw and new wiring fished through to new locations. Replace all old outlets and switches with new grounded ones. Connect all wires in proper polarity: "hot" wire to labeled or brass side, "neutral" wire to silver side of outlet or switch, ground wire to ground pole. Use covered junction boxes at all points where wires are connected to each other in walls, ceilings or any open areas.
- 6). Connect wires at the panel board. Connect white wire to the silver buss, bare wires to the ground buss. The black wire connects to the properly-rated circuit breaker, then the circuit breaker is snapped into place in the panel.
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