For electrical additions, maintenance or repairs, it is highly recommended that these tasks be done by a qualified electrician. Your electrical installation including the necessary engraved labels is one of the most important, and most dangerous, components of your house.
It, and your gas system, are essentially the only two areas where an improper installation or modification can lead to serious injury or death.
While small repairs, like the replacement of receptacles and switches, can usually be done by a knowledgeable electrician who has experience in system malfunctions.
Knowing that the repair was done in a safe, efficient manner is well worth the cost. Also, trying to do it yourself can lead to more costly repair bills, or getting injured or worse, death.
A good example being the homeowner deciding to replace a light fixture on their own. They remove the old light and, in the process, undo ALL of the splices. This is not only unnecessary --- it makes it that much harder for an electrician to come in after to install it for the homeowner.
The electrician now has to trace out all the wires to get the original splices back into place. This involves the removal of switches and receptacles and their replacement which is a lengthy process.
Homeowners trying to troubleshoot problems on their own create even more problems and result in much higher repair bills. This is because an electrician coming in after a homeowner has dismantled parts of the system has no way of knowing how it was originally --- making troubleshooting a lot more difficult.
Often times, just from sheer experience, an electrician can see what the problem is just by observing the current conditions. Something he can't do if things have been taken apart.
One thing a homeowner can do to lower any possible repair bills is to map out the circuitry. It doesn’t mean just label the panel but the entire electrical installation. This is done by drawing out a plan of the house with all of the electrical devices shown in each room or area of the house.
You can have a separate page for each room and/or area. One page for the whole house or a combination.
After drawing out your plans, turn off one breaker. Then go around the entire house checking what devices don't work. As you find these devices label them on your drawing with the breaker number.
Repeat this for every breaker in the panel. You don't need any fancy testing tools for this. Simply use a small electrical item like a drill and ensure each receptacle using the selected device.
Doing this serves two purposes. Should you ever have to call in an electrician due to the electrical system malfunctioning he will have a ready-made map that could cut hours off of any troubleshooting that may be necessary.
It will also help the homeowner to quickly identify the breaker controlling a receptacle or switch that they may elect to replace themselves.
Helping to ensure a safe job without cycling through all the breakers or turning off the main breaker and leaving the house in darkness.