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Diagnostic Flowchart
For an Electrical Outage in a Home

The chart below is not meant for every kind of electrical problem, just an outage that does not seem to be due to a tripped circuit breaker. If you know that the cause of your electrical outage is a circuit breaker or GFCI outlet tripping, the main Diagnostic Tree will be more helpful, as it will for an outage you have had in the past that is not currently happening. That Tree is also where shocks and flickering, dimming, or brightening lights are dealt with.

When outlets and lights in your home are not working, this is often due to a poor wire connection somewhere on the circuit. It is called an "open." To determine whether your problem is an open, and to find the location where a loose wire may need repair, follow this Diagnostic Flowchart. (If you are a more step-by-step person, you can go through the same process using the Yes/No diagnostic pages.)

Chart for diagnosing household electrical outage

Getting the chart image to print out (odd size) might mean trying different methods. (I have had luck printing from the "Windows Picture and Fax Viewer" Preview after saving the chart itself somewhere.) Simply previewing a print of this web page and then printing "page 2" or "page 3" may work; the following table-version will probably land on page 3.

START HERE. Does a test lamp [portable, turned-on, works in a good outlet] work in all outlets in/on the house when all wall switches are on (note which outlets are dead)? You no longer have a problem of this sort. If things act up again, come back. It is likely that the power company line or the main breaker in your panel has a problem, especially if any 240-volt appliances are not working normally. The power company can determine if it is their problem... But if a regular double breaker in the panel is labeled "Submain" or "Main," it might need to be replaced.
Do all permanent light fixtures in/on the house work when good bulbs are put in them and their switches are tried?
no↓ no↓
Do all permanent light fixtures in/on the house work when good bulbs are put in them and their switches are tried? no
Is the total number of not-working "items" ["duplex" receptacles plus permanent lights; not switches] less than 20? no
Are there any dead outlets ELSEWHERE THAN IN bathroom, garage, outside, kitchen, dining, or laundry? yes
Near your breaker panel if you have a set of generator switches, be sure they are all set in the same position ("Line"). Now at the breaker panel(s) itself push each breaker's handle [except the main breaker], one by one, first VERY forcefully Off (hear any click?) and then after a second or two push it firmly to On. Did any breaker seem to not stay firmly On then (or seem to make a buzz or hum noise for a moment)?
Look hard for ALL ground-fault receptacles in/on the house [they have "RESET" and "TEST" buttons on the face of them and are likely found in bathroom, garage, outside, kitchen, dining or laundry]. Push hard on only the RESET of all of them, starting with those closer to your breaker box. Now are the dead items still dead?
You have reset a GFCI that had tripped for a condition that is now gone. no
yes↓ no↓
Your breaker is tripping for a reason addressed elsewhere. For instance, a short circuit. yes
Are the dead items still dead? Are the dead items still dead?
You have successfully reset a tripped breaker. It had tripped from an overload or a short circuit (that is gone now) or from an overheating connection at that breaker (replace some day in a different slot). no
Now use the Jiggle Method as follows. Have all breakers on. If any outlets are dead, plug the turned-on test lamp into one of them. Also for all the permanent lights that are dead, turn their switches on (if you can tell which way is on). You will be going around to items in different rooms to try to bother a poor connection back into being good. Since the lamp or lights will flash on for a moment when you succeed, some undistractable person needs to watch them the whole time and to let you know the moment they see this. If you have any dead outlets, now pick some other plug-in item (night light, extension cord, etc - it doesn't have to be turned on) and plug it in to one dead outlet after another, wiggling it from side to side a bit when it is plugged in. (Any flash yet?) Next do the same at WORKING outlets in the same area and in nearby rooms, especially areas closer toward the breaker panel. (Any flash?) Next remove the covers from all the dead lights' switches and from other switches within 20' of the dead area, and with a wood spoon or plastic chopstick (no metal) poke at any bundles of wires behind the switches; you'll probably have to loosen the switches' screws to do this. (Any flash?) Finally, loosen any dead ceiling lights one by one (and after that, good ones within 20' of the dead area), poking as you did at the switches. Did the test lamp or dead lights flash on during a particular action of yours?
yes↓ no↓
A connection you were disturbing at the outlet, switch, or light you were at when the lights flashed needs to be improved, repaired, or replaced. A wire was getting too loose from other wires in a "wirenut" or from its attachment to a receptacle. The wire might even look ugly and need to be cut back before making a new connection. This jiggling doesn't always reveal the culprit, so you can still try redoing connections at any of the dead or live places you were bothering. Or maybe it is time to find a good electrician.

"Never did I expect to find such a glut of free, useful information from one site! You have restored my faith in the internet as a useful resource." -Ryan, VA

"Last night I used what I learned from your site to diagnose and fix a multiple switch, fixture and outlet problem I was having on a house I am about to sell. It turns out, one of the nearby working outlets in the room had a loose backstab wire. I followed your directions to plug in a light in one of the failing outlets and then jostling wires in each working outlet until I found the one that was not working. Thanks for saving me a load of money!" -Lou

"Thanks a lot. With your diagnostic tree, we found the source and fixed it in 10 minutes after spending hours yesterday trying to figure out which outlet was the culprit." -Pat

© 2011 Larry Dimock

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