In order to locate the source of an electrical problem, we should use a thinking process that quickly isolates the problem to only a few possible causes. So before going on to solve specific problems we should try to relate to the entire electrical system. By doing so, we should be able to reduce the number of possible causes. In the event that it is necessary to call for a contractor, we can explain the nature of the problem in more detail. This will save time and money.
The Thinking Process
When an electrical problem occurs, the first question should be “how local is this?”.
For example, if the lights in your house have gone out, the problem could be just in your house or it could be your local transformer supplying a few homes. It could also be the entire town that is without electricity. If the street lights are on, the whole town isn’t without electricity. If your next door neighbor has electricity and you do not, then there is likely a problem at your home.
The next question should be “have we lost ALL of the supply?”. In North America it is possible to lose one “live leg” of the supply coming into the house. If this happens, you will have some lights and receptacles that work, while others do not. In the kitchen (in Canada) one half of each 15 Amp ( but not the 20 Amp type) counter top receptacle may be ON while the other half is OFF. So you can do a quick test by plugging in an appliance to both the top and bottom outlet of a receptacle. Another indication that one “live leg” is disconnected is that the electric heating, AND the stove AND the dryer do not work properly. Notice that I used AND. If the stove does not work correctly but the dryer does work correctly, then you have narrowed the problem to the stove circuit, assuming that they both come from the same panel. If you have a main panel and a sub-panel you may have isolated the problem to the sub-panel.
If you have an older home with a main switch and two fuses, the most likely cause is that one fuse has blown while the other fuse is OK. One live leg could also be lost when a cable breaks in a storm. The blown fuse is the more common cause.
The next question then would be “do the stove, dryer, heating or air-conditioning all work?” If you can say yes to this you are on your way to dealing with only individual circuits. Once you get to this point you should be thinking “what has been happening that could have caused a problem?”. For example, if you have carpenters working in the house it is possible that a nail was driven into a cable. If you have children playing in the basement, they may have switched some breakers off (just to see what would happen). However, if nothing unusual is going on, you may start to suspect worn parts in the system.
This thinking process takes only a few seconds when we know how to do it. So usually we can isolate a problem to one circuit very quickly. If we cannot do this very quickly there is most likely a problem at the electrical panel or in the meter enclosure. Sometimes wires can overheat to the point where the insulation “breaks down”. If several wires from different circuits are bunched together, a problem may appear on more than one circuit at the same time. So we should go the panel and check for a burning smell. The cover can still be on the panel. Next we can feel for heat at the panel. Look for signs of burned paint on the panel.
When a connection becomes slack in a wire carrying a lot of current, heat is produced. This can cause the metal connector to expand, making the connection more slack. You will normally notice flickering lights or other symptoms when this happens. If it is not dealt with, the insulation becomes damaged and this can affect other circuits.
By using the thinking process described, you should be able to quickly focus your trouble-shooting on a particular circuit.