The Circuit Detective

Diagnosis in a Nutshell: Basic Troubleshooting

Here is a quick, concise look at how to find the source of home wiring problems.

• Turn it on. If that doesn't help,
  Replace it.

• Reset all breakers and, AFTER that, all GFIs.
• If things still don't work,
  Locate a bad connection by checking and improving those at the interface between the dead things and any live things nearby (especially of that circuit, if you know it)
• If they still don't work,
  You can replace the breaker and check the neutral connections at the panel.
• If more than one circuit is affected,
  Be sure that main and submain breakers are not blocking the voltage; confirm that any electric range or dryer will not heat well;
  Then call the power company.
• If the breaker or GFI retripped upon your resetting,
  • Unplug or switch off everything you can (especially on that circuit, if you know it); then try resetting again.
  • If it holds,
    See which thing you undid sets it off.
  • But if it didn't hold,
    Break the circuit's hot apart midway along the circuit and try resetting; continue reconnecting the circuit and breaking the hot apart at other places (one at a time) to narrow down where the fault is occurring.
  • If it was the GFI retripping, go back after these procedures and break the neutral apart in a similar way in case this will narrow the location down.

• Over time, keep track of which lights and even receptacles are affected and which are not.
• If the irregularity is limited to part of a circuit,
  Check/improve connections at the interface between the troubled things and the good of that circuit.
• If it affects the whole circuit,
  Check the circuit's panel neutral or replace the breaker.
• If the unusual behavior extends to more than one circuit,
  • Check all panel neutrals.
  • See if good voltage is sustained at the time of blinks, etc. at all terminals of the main breaker and of any Submain breaker.
  • If these procedures suggest the power company's connections are at fault,
    Have them check their things.

• Confirm which item(s) are hot, using a tester, then
• Turn off circuits, one by one, to see which one is to blame, then
• Unplug, disconnect, or switch off things of that circuit (especially the shocking thing), and
• If one of these actions eliminates the hotness,
  • Have the item responsible replaced or repaired.
  • Then have the item and its circuit grounded better.
• But if there was still shock hazard present, break the hot wires apart in various places along the circuit, as outlined above for solving breakers tripping, but noting instead whether hotness is affected.
• If metal piping was hot, check all accessible pipes for contact with wires.

• Learn more about circuit connections (and testing), and work only at the areas that had been modified.

Other pages that take you through a process similar to this nutshell but with more detail:
Diagnostic Flowchart
Diagnostic Tree
Troubleshooting Strategy - Stage 1 - Symptoms to Causes
Troubleshooting Strategy - Stage 2 - Locating the Cause

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