The dreaded dead short. No, I'm not talking about a bad horror movie or an outdated fashion statement, I am talking about something much more dangerous. A dead short is when an electrical circuit has zero resistance.
This can result from the "hot" electric feed coming in contact with a metal object, like a metal outlet box or with the ground or neutral wire. Your initial sign that you may have a dead short will be a tripped breaker. Here is how to troubleshoot an electrical dead short.
An electrical dead short can be a dangerous situation if it is not taken care of immediately. While it may be a tougher electrical job than most people are used to, you can easily make the repair in most cases. However, dead shorts can sometimes be difficult to find, which is why you will need the help of another person. For the first part of the investigation, leave the breaker OFF.
Your first step is to determine what area of the house is affected by the power loss due to the breaker being tripped. You can do this by checking the lights in the rooms and by using the voltage tester to check for power in each of the outlets.
Once you find the affected area, closely look at the outlets, switches and light fixtures within the area. You are looking for any burns or scorch marks. When a dead short occurs, it creates a shower of sparks and often the sparks will shoot out of the outlet or switch leaving behind the tell-tale signs of a black scorch mark.
If you have checked everything thoroughly and you cannot find the source of the electrical dead short, then it is time to take the next approach. One person will have to stand in the area of the power loss (preferably in the middle of it) and the other will have to go to the electrical panel.
Make sure you can hear each other. If the panel is too far away from the problem for you to be able to hear each other, try using short wave walkie talkies to communicate or talk to each other on cell phones.
When both of you are ready, try to reset the breaker. It will instantly trip. In the area where the electrical dead short is, the person standing there should hear a definitive "pop" sound. He should be able to narrow down the area of the electrical dead short.
Once you have the general area, like one wall in a room, it is time to dig deeper. Leave the breaker OFF. Look at the wall where the "pop" sound came from and check the outlets and switches. You can actually sniff the outlets or switches and you will usually smell a burned odor which will also help you isolate the area.
If you still cannot find it, begin removing the faceplates from the switches and outlets. Again, keep your eyes out for scorch marks.
Once you find the culprit, make your necessary repairs. Now, with the switch or receptacle replaced, try resetting the breaker again. It should not trip this time. Go back to the affected area and test for power in all of the outlets once again.
Some electrical dead shorts can be very difficult to find. If you cannot locate the problem quickly, you may want to call a licensed electrician to troubleshoot the job. You want to avoid resetting the breaker a number of times because you may actually blow the electrical dead short open, leaving an open feed somewhere within your walls. Electrical dead shorts are dangerous, but they can be easily repaired if found quickly. Of course, if you have an electrical dead short but do not feel comfortable working with electric, even dead wires, call an electrician immediately.