Q. My very old house could use some electrical work – outlets, switches, etc. It looks easy to install them and the wiring. What are some of the common errors people make so I can avoid them?

It might look easy to do electrical work, especially if you watch some of the home-improvement shows on television, but it actually is quite involved. This is not to say you cannot do it yourself, but you should spend some time studying the procedures before attempting them yourself.

As we all know, electricity can be very dangerous. An electric shock could stop your heart and kill you. Many house fires are started from faulty electric wiring. If you wire your home yourself and a subsequent owner is harmed because of errors you made, you may be liable for damages.

All wiring must meet the National Electric Code, a standard for safe installation of electrical wiring and equipment in the United States. You should be able to find the code on the Internet or at your local library. You don’t have to memorize it all, but be familiar with the areas that cover your specific projects.

In addition to reading the codes, visit some building sites in your area. Find a home with the wiring already installed, but not the drywall. Study the procedures and techniques after the work has been inspected. Take your code book along for reference.

If you are at all unsure of the proper procedures, do not attempt to do the work yourself. Electrical problems are not like plumbing problems, where leaking water is often a clue that something is wrong. Electrical installation errors may not be apparent until there is a heavy load on the line or after several years, when the insulation fails.

• In older homes, a typical error do-it-yourselfers make is to install a grounded electric outlet receptacle in place of an old two-prong outlet. A receptacle without a proper ground wire can be very dangerous. When someone sees a grounded outlet, they just assume it is grounded and can get shocked if an appliance plugged into it malfunctions.

• Never put a metal outlet box cover over an ungrounded outlet. If a wire shorts out inside the conduit box and switch, the cover plate will be hot. If you touch it and are grounded yourself, the electricity will follow through your body.

• Make sure to follow the codes for matching the size of the wiring to various size circuit breakers. A heavier (thicker) wire can carry more electric current without overheating. Thinner wire is easier to work with and pull through walls, but it can overheat and cause a fire or degrade the insulation.

• The electric conduit box must be flush against an interior combustible wall surface. When rooms are remodeled with paneling, there may be a gap between the box and the wall surface. In this situation, install an extension ring over the old box.

• Also, make sure the conduit box is securely attached to the framing. To make the cover fit nicely, some people allow the box to float inside the wall. Pay attention to the length of the stripped wire end so it meets code. If it is stripped too far back, bare wire may be exposed in the box.

• When stapling wires to studs, drive them in straight and secure, but not excessively tight so they cut into the insulation.