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Troubleshooting a dead receptacle or light, Basic Terminology & Other info

Troubleshooting a dead receptacle or light, Basic Terminology & Other info

Old 03-22-11, 01:31 PM
ray2047's Avatar
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Troubleshooting a dead receptacle or light, Basic Terminology & Other info

Before we get to the troubleshooting lets get acquainted with some terminology.

Receptacle: A place where you plug something in.
Sometimes called an outlet.

Outlet: Anywhere power can be accessed. Examples are
receptacles and lights.

Wire: A single conductor.

Cable: A group of 2 or more wires (conductors) in a single
sheath. It may or may not have a ground wire. The sheath may be cloth, plastic, or metallic.

Conduit: A metal or plastic pipe that carries a group of wires. At the fixture box it looks like a pipe with a nut on it entering the box.

2-conductor cable: A cable with 2 wires. May or may not also have a bare ground wire. Usually Black, white, bare. Other common designations, 14-2 or 12-2 with the number before the dash indicating size.

3-conductor cable: A cable with 3 wires. May or may not have a ground wire. Usually Black, white, red, bare. Other common designations, 14-3 or 12-3 with the number before the dash indicating size.

Back Stab: A method of attaching wires to a receptacle or switch that is done by inserting wires into holes in the back. Considered by some as more pron to failure because only light weight springs contact the wires. Not to be confused with back wired. See below.

Back wired: A method of wiring that uses a pressure plate tightened by a screw. Often found on GFCI Receptacles and commercial grade receptacles.

GFCI Receptacle: A receptacle that provides personal safety by shutting off power when current leakage is detected. It can be identified by test buttons in the center of the receptacle.

Troubleshooting a dead receptacle or light

This Will talk mostly about receptacles but trouble shooting lights is similar and in fact a failed receptacles problem could be at a light and a failed light problem could be at a receptacle.

Check the breaker box. A tripped breaker often doesn't look tripped. Turn the breaker all the way off then on. If it trips immediately do not try to reset. Please post to the forum.

Check for a tripped GFCI. The GFCI could be anywhere. A bathroom, kitchen, basement, garage, attic, outside. I have seen back yard receptacles on a upstairs bathroom circuit at the front of the house. It doesn't matter if it is a room that shouldn't be on a GFCI. The receptacle may be an add-on that someone just ran from an accessible cable. Sometimes the GFCI's are forgotten or never noticed behind furniture. We had one poster find the culprit hidden behind the water heater. Once you're sure there is no GFCI move on to the next step.

Where to start. The problem may be at the last good device or fixture or the first bad fixture or device. No sure way to know how the wiring is run but an educated guess is the fixture closes to the breaker box is first and the one furthest from the breaker box is last. Often the ones in between will be in order. However on some houses, especially older ones, all of the lines may run from a ceiling box for a light, sort of like legs of a spider.

Back stabbed Wires. Move any back stabbed wires on the switches and receptacles to the screws.

Wire nuts. Wire nuts and the wires in them can corrode or become loose. You need to remove and check all wire nuts on the circuit. They may be in the receptacle box or at a light or at a switch.

If you still haven't found the problem post to the forum and we will help you find it. Let us know every thing you have already tried. Let us know if it ever worked. Let us know if any pictures have been hung lately or any other construction.

Addendum: While GFCIs do occasionally go bad because they contain electronics non GFCI receptacles are just mechanical and while they can wear out and no longer grip the plug tightly there really isn't much to go wrong. Replacing a non GFCI receptacle is unlikely to fix the problem though rewiring it may correct an unnoticed problem. The best way to test a GFCI is remove the wires on the load side and try it with just line connected. If it doesn't trip the problem is likely downstream.

Last edited by ray2047; 06-27-14 at 07:22 AM.
Old 09-15-12, 07:52 AM
Tolyn Ironhand's Avatar
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Other helpfull information

Here is some good info about the difference between GFCI and AFCI and where one or the other is required. Based on the 2011 NEC


To find what code cycle you are on go here:

Mike Holt

Standard voltages:

Here is a list of the standard voltages found in the US. These voltages are nominal and can deviate +/- 10% and still be within tolerance. Manufactures/people commonly use 110v, 115v to describe 120 volt, and 220v, 230v for 240 volts. While this is technically wrong, it is still often used.

120V (phase to ground/neutral)
208V (phase to phase, or phase to ground/neutral in a high leg 3 phase Delta system)
240V (phase to phase)
277V (Phase to ground/neutral, 3 phase Wye system)
347V (phase to ground/neutral, 3 phase Wye system)
480V (phase to phase)
600v (phase to phase)

Electrical systems that are most common are:

120/240 Single phase. Found in most residential homes
120/240 Three phase Delta high leg. This is where you find voltage of the B phase is 208 to ground/neutral) Very dangerous!
120/208Y Three phase. Found in many commercial buildings.
277/480Y Three phase. Also found in commercial buildings for lighting, heating and cooling.
347/600Y Three phase. Found in some industrial buildings/applications.

Last edited by Tolyn Ironhand; 04-19-15 at 05:53 PM.

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