|
The National Electrical Code (NEC) has a few things to say about how a home should and shouldn't be wired. You should spend time studying the actual code to make sure you do the job right. The NEC isn't just a bunch of arbitrary requirements designed to make your life more difficult as an installer; the guidelines are designed to make your house as safe as possible.
 | Check out the Handbook of the NEC Codebook. It has the complete code text in addition to explanatory notes and diagrams. |
Here are a few specific requirements to keep in mind as you rough in your wires:
- Bedrooms: Arc Fault Interrupter (AFI) circuits are only required on bedroom circuits. An AFI is a circuit breaker that monitors the current; it recognizes the characteristics of an electric arc and trips when it detects one. Brush motors like those found in vacuums, mixers, or drills produce an arc when running. Sometimes false tripping can occur if using these types of devices on AFI breaker-controlled circuits. It's best if the bedroom hall receptacle(s) are supplied by non-AFI circuits to power vacuum cleaners for cleaning the bedrooms if false tripping occurs.
- Smoke detectors: If a smoke detector is installed in a bedroom, it must be on an AFI circuit. Of course, smoke detectors must also have battery backup power as well. The electrical code doesn't specify where smoke detectors should be placed, but building codes usually require them in all bedrooms and bedroom hallways. Consider using one or more combination carbon monoxide-smoke detectors. Make sure the interconnect feature works with your smoke detectors.
 | Smoke detector systems are required to have an interconnect feature. If one detects smoke, all interconnected detectors sound an alarm. The interconnect wire is usually orange, which should be connected to the red conductor on a three-conductor cable. |
- Bathroom, laundry, kitchen, or dining-room receptacle circuits: All of these circuits must be supplied by 12 AWG wire. This is also true of any receptacle circuit that will have more than a 12-amp load. Lighting circuits in these locations can be wired with 14 AWG wire.
- GFI wiring: When pulling the wires, the power wires at a box can usually be marked with the letter P — exceptwhen the wiring connects a GFI receptacle to a second receptacle. On a GFI feed-through system, the power-in wire connects to the line terminal, and the power-out wire connects to the load terminals on the GFI receptacle. It is important to identify the in-out wires at rough in so the GFI is connected properly.
- Existing wiring: The electrical code doesn't mandate that you bring an existing residence up to code. It only requires that any new work you do conforms. However, the existing wiring in your home isn't immune from scrutiny. If an electrical inspector finds something she considers hazardous, she may instruct you to correct the problem. Such problems may include bare wires, open splices, or extension cords used for permanent wiring. If you refuse to solve these problems, the inspector can order the power company to disconnect your power.
- Existing receptacles: If you plan to replace a receptacle in a kitchen, bathroom, garage, or other location where a GFI outlet is required, you must replace the outlet with a GFI unit. This is true even if the old receptacle was installed before GFI outlets were required. If the house uses older two-wire conductors, mark the new GFI receptacle with No ground is present. You can feed other three-prong receptacles from this ungrounded two-wire circuit. They will be ground-fault protected, but mark them with No ground is present; GFCI protected.
|
