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Home Improvement

2002-06-01 15:05:00

Replacing the wiring in your home?

Question:  Our house is 40 years old. Some of the wiring is copper and some of it is aluminum. I would like to replace it and do the job myself. Can I and then get an inspector to approve it? What will I need?

Answer: In most places, homeowners are allowed to do their own wiring. In some, they're not. Check with your local electrical inspector. Most places won't permit you to do wiring on other's homes for money without a license. Nor are you permitted to do wiring in "commercial" buildings. Multiple dwellings (i.e. duplexes) are usually considered "semi-commercial" or "commercial". However, many jurisdictions will permit you to work on semi-commercial wiring if you're supervised by a licensed electrician - if you can find one willing to supervise.If you do your own wiring, an important point:Do it NEAT and WELL! What you really want to aim for is a better job than an electrician will do. After all, it's your own home, and it's you or your family that might get killed if you make a mistake. An electrician has time pressures, has the skills and knows the tricks of the trade to do a fast, safe job.Below are a few recommendations that are in excess of code, because we feel that it's reasonable, and will impress the inspector.The inspector will know that you're an amateur. You have to earn his trust. The best way of doing this is to spend your time doing as neat a job as possible. Don't cut corners.  Exceed specifications. Otherwise, the inspector may get extremely picky and fault you on the slightest transgressions.Don't try to hide anything from the inspector.Use the proper tools (i.e. don't use a bread knife to strip wires, or twist wires with your fingers. The inspector won't like it, and the results won't be that safe.  It takes longer, and you're more likely to stick a hunk of 12 gauge wire through your hand that way).Don't handle house wire when it's very cold (i.e. below -10C or 16F). Thermoplastic house wire, particularly older types become very brittle.In regards to tools:First, there's the obvious -- a hammer, a drill, a few screwdrivers, both straight and Phillips-head. For drilling a few holes, a 3/4" or 1" spade bit and 1/4" or 3/8" electric drill will do. If you're doing a lot, or are working with elderly lumber, we recommend  a 1/2" drill (right-angle drills are wonderful and can be rented) and 3/4" or 1" screw-point auger drill bits. These bits pull you through, so they're much faster and less fatiguing, even in 90 year old hardwood timbers.Screw-driver bits are useful for drills, especially if you install your electrical boxes using screws (drywall screws work well).For stripping wire, use a real wire stripper, not a knife or ordinary wire cutters. Don't buy the $3 "combo stripper, crimper and bottle opener" types. You should expect to pay $15 to $20 for a good "plier-type" pair. It will have sized stripping holes, and won't nick or grab the wire - it should be easy to strip wire with it. One model has a small hole in the blade for forming exact wire loops for screw terminals. There are fancier types (autostrip/cut), but they generally aren't necessary, and pros usually don't use them.A pair of diagonal side cutter pliers are useful for clipping ends in constricted places. Don't use these for stripping wire. You will need linesman pliers for twisting wires for wire connectors.You should have a pair of needle-nose pliers for fiddling inside boxes and closing loops, but it's better to form wire loops with a "loop former hole" on your wire stripper - more accurate.If you're using non-metallic cable, get a cable stripper for removing the sheath. Or, do what some pros do, they nick the end of the sheath, grab the ground wire with a pair of pliers, and simply rip the sheath back using the ground wire as a "zipper", and cut the sheath off. You shouldn't try to strip the sheath with a knife point, because it's too easy to slash the insulation on the conductors. For any substantial amount of work with armored cable, it's well worth your while to invest in a rotary cable splitter (usually around  $20). Hack saws are tricky to use without cutting into the wire or the insulation.Three-prong outlet testers are a quick check for properly-wired outlets. About $6. Multimeters tell you more, but are a lot more expensive, and probably not worth it for most people. A simple voltage sensor, which can detect potential through an insulated wire not supplying any devices, is extremely helpful; they cost about $10.You should have a voltage detector - to check that the wires are dead before doing work on them. Neon-bulb versions are inexpensive  ($2-3) and work well. If you get more serious, a "audible alarm" type is good for tracing circuits without a helper. For running wires through existing walls, you need fish tape. Often, two tapes are needed, though sometimes, a bent hanger or a length of thin chain will suffice. Fish tapes can be rented.Electrical tape. But remember, a good and competent wiring job will need very little tape. The tape is useful for wrapping dicey insulation in repair work. Another use is to wrap around the body of outlets and switches to cover the termination screws. I don't do this, but drywall contractors prefer it (to prevent explosions when the drywall knife collides with a live outlet that has no cover plate).