How to Repair a Shorted Electrical Outlet – Part 1

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This tutorial explains how to replace a shorted electrical outlet and repair the burnt and charred wire insulation.

Electrical Outlet Hissing Noise

The problem started when my son complained of hearing a hissing or sizzling noise from a wall outlet in his bedroom and temporarily losing power to some of the other outlets and lights. The circuit breaker wasn’t tripped and power would come back On by itself at the affected outlets and lights.

I asked my son to point out the outlet that was sometimes making the hissing noise. After shutting Off the electricity at the circuit breaker panel and verifying the electricity was Off with a voltage detector, I removed the outlet face plate and mounting screws. What I discovered was shocking! (Pun intended.) The outlet side terminal screws were not tightened on the NM-B 14/2 wires! The wires were just looped around the terminal screws making a loose connection that resulted in an arc short and heating that burned and charred the wire insulation. See the excellent “Short Circuit” and “Poor Connection” topics in the presentation by Dr. V. Babrauskas at 2001 International Fire & Materials Conference as posted on

Shorted Electrical Wall Outlet: Burned and Blackened Wires

I could tell that the outlet is wiring is original from when the home was built by the metal crimp sleeve connectors on the ground wires and white primer spray painted on the wires after the drywall was installed. Why weren’t the side terminal screws properly tightened? My guess is the electrician got distracted during the job, or maybe it was quitting time that day, and forgot to tighten the terminal screws.

I’m lucky the electrical arc short didn’t cause a fire.

Here’s a closeup of the burned and charred insulation on the neutral (white) wire and blackened terminal screw – that screw should be silver colored like the other screw next to it:

Burned Wire Insulation on Shorted Electrical Outlet

The plastic case of the outlet was melted where the wires touched the case:

Shorted Electrical Outlet Wiring

Both the neutral (white) and hot (black) wires were loose (a wiring fault), resulting in shorting and arcing that heated the wires and burned the insulation:

Shorted Electrical Outlet: Hot and Neutral Wires Burned and Pitted

Other Wall Outlets Lose Power

Why did the power to the other outlets and lights temporarily go out and then come back on?

The reason for the intermittent power is because the outlets are wired in Series and the loose wires on this outlet are the source of electricity for those “downstream” outlets and lights (desk lamp and closet light). When the computer, Xbox, stereo, TV and lights on those downstream outlets were turned On, the electrical load of those devices caused the loose receptacle wires to heat up due to the poor (high electrical resistance) connection. The result was technically a “brown out” where the loose outlet wires couldn’t provide sufficient electricity to meet the power loads, so power was lost and the TV, desk lamp, etc. wouldn’t operate. Meanwhile the loose outlet wires would heat up like the wires in a toaster due to the loose/high resistance connection to the outlet with arcing and burned insulation. The arcing (electrical sparking) at the loose connection makes the hissing or sizzling noise.

Series Wired Electrical Wall Outlet: Shorted Wires and Power Loss

How to Repair a Shorted Electrical Outlet

The following steps are required to repair the shorted wall outlet and burnt wire insulation:

  • Repair the burned insulation on the copper wire conductors
  • Replace the old wall outlet with a new electrical outlet

Because I’ve written a tutorial on how to replace an electrical outlet, the remainder of this project will focus on repairing the burned insulation on the individual wires (copper conductors) of the NM-B 14/2 cable. The burned insulation was repaired with Raychem Heat-Shrink Tubing which is rated for 600 volts and up to 275 °F (135 °C) operating temperature, which equals or exceeds the 600 volts and 194°F (90°C) limits of the NM-B 14/2 wire insulation. I also used Scotch 35 Vinyl Electrical Tape to code the repaired wires to avoid confusion for future electricians doing work on the outlet.

Shorted Wall Outlet Repair: Heat Shrink Tubing and Electrical Tape

Closeup of the Raychem Heat-Shrink Tubing Kit, Part #CPGI-RNF-100-ASRT-4N-BLK, which is available at Home Depot for about $18.

Electrical Wire Repair: Raychem Heat-Shrink Tubing: Rated 600 volts and 275°F

NM-B Wire Insulation Repair Options

There are several ways to repair the shorted outlet wires:

  1. Replace the entire run of NM-B 14/2 cable with the burned insulation from this outlet to the next outlet in series.
    This would require major work tearing open the drywall, removing cable staples, etc. I really didn’t want to go there nor is it necessary in this situation.
  2. If the wires are long enough, cut the wires back beyond the burned insulation.
    The National Electrical Code (NEC) 300.14 requires the wires extended a minimum of 3 inches outside the electrical box. If I cut the wires, I would be at or below the 3 inch minimum length requirement. I also don’t like shortening wires because they never get longer.
  3. Cut back the burned wires and wire in a pigtail connection to lengthen the wire so it extends at least 3 inches past the outlet box.
    This is possible and I would go with this option if the outlet box only had two (2) NM-B 14/2 cables, however it has three (3) NM-B 14/2 cables and the box is at it’s maximum wire fill allowance for an 18 cubic inch single gang outlet box. A pigtail wouldn’t increase the wire fill count per the NEC calculations, but I’d be cramming wire nuts and more wires in a too small box. Per the NEC wire fill calculations, the volume allowances for this outlet box are: 6 power conductors, 1 ground and 2 for the receptacle for a total of 9 volume allowances. For 14 gauge wire 2 cubic inches of box space are required per volume allowance. 9 volume allowances * 2 cubic inches/volume allowance equals 18 cubic inches; which equals the 18 cubic inch volume of the outlet box.
  4. Strip off the burned insulation and wrap the exposed copper conductor with electrical insulating tape.
    Easy, quick and very inexpensive. This is probably what most electricians would do.
  5. Strip off the burned insulation and cover the exposed copper conductor with an appropriately rated heat-shrink tubing.
    I liked this option the best and is how I made the repair. The extra effort and cost were minimal and it looks nicer compared to wrapping the wire with electrical tape.

Electrical Tape or Heat-Shrink Tubing?

There are recommended repair methods for the outer insulation jacket, but not for damaged conductor insulation in a terminating situation as I have with the shorted outlet wires. If this were damaged to the inner insulation or copper conductors in a cable span, the solution would be to splice in a new section of cable with two junction boxes.

To confirm if electrical tape or heat-shrinking tubing were acceptable conductor insulation repair methods, I called the Southwire Company, the manufacturer of Romex® NM-B cable, and explained my problem to a product support engineer. The engineer said that stripping off the burned insulation and wrapping the wire in electrical insulating tape would be an acceptable repair, but liked heat-shrink tubing better. Adhesive shrink wrap tubing would be best to prevent any possibility of the tubing slipping on the wire, however adhesive tubing in such a small diameter (1/16″ to 1/8″) probably wasn’t available. The minimum requirements are the heat-shrink tubing be rated for at least 600 volts, meet or exceed the NM-B cable operating temperature and recognized by Underwriter’s Laboratories (UL Standard 224, 600V/125˚C). The Raychem Heat-Shrink Tubing used in this repair meets all three requirements.

Shorted Electrical Outlet Repair

If you’re not comfortable working with electricity and electrical wiring, please hire a licensed electrician.

Recall that the electricity is shut off at the circuit breaker panel. Never work on live circuit to prevent shock, injury and/or death.

To begin the outlet repair:

  1. I disconnected and straightened all the wires from the old electrical outlet.
  2. Working with a helper at the circuit breaker panel while on the mobile phone, I asked my helper to turn on the electricity.
  3. Being extremely careful not to touch the live wires, I identified the line side wires (i.e. the wires that provide power to the outlet from the circuit breaker) with a non-contact voltage detector. I also verified there was no power on the other wires.
  4. I asked my helper to turn off the circuit breaker and verified the circuit was dead with the voltage detector.
  5. I coded (tagged) the line side hot (black) and neutral (white) wires with red and white electrical tape as shown in this photo:

Shorted Wall Outlet Repair: Identify and Code the Wires

The damaged insulation on the 14 gauge copper wires must be stripped back to the undamaged insulation. The worst of the charred insulation has fallen off the wires as I handled and straightened the leads:

Shorted Electrical Wall Outlet: Burned Insulation on the NM-B 14/2 Wires

Here are the wires after stripping off the burnt and swollen insulation are shown in this next photo. This was necessary such that the 3/32″ diameter heat-shrink tubing would fit over the undamaged insulation.

Shorted Wall Electrical Outlet Repair: Burnt Insulation Stripped from Wires

I next removed the tarnish and oxidation from the copper conductors with a bit of steel wool, mainly for appearances sake.

Shorted Electrical Wall Outlet Repair: Stripped and Polished Wires

This project is concluded in How to Repair a Shorted Electrical Outlet – Part 2.

Thanks for reading,

Bob Jackson

Copyright © 2018   Reproduction strictly prohibited.


  1. Sarah January 9, 2016 at 9:07 pm - Reply

    This is very helpful – thank you! I’m repairing the burned out white wire in my dishwasher junction box. (It melted the nut! It’s been there 12 years, not sure why it suddenly burned up.) I like the heat-shrink tubing and am glad to hear that it’s suitable for this. I’d previously just used it on our low-voltage outdoor lighting.

  2. jimmy January 17, 2016 at 1:12 pm - Reply

    I replaced the outlet the right way and still no power. breaker is on plug in light did not work. do i need to hit reset button on receptacle? it will not click what do i do next?

    • Bob Jackson January 17, 2016 at 2:51 pm - Reply

      A receptacle with small “Set” and “Reset” buttons is a Ground Fault Circuit Interrupt (GFCI) receptacle. A GFCI outlet must be wired correctly because it has “line side” (power from the circuit breaker) and a “load side” (downstream protected devices). If the wiring for the line and loads sides are reversed the outlet will not work. It also requires a good ground connection. Note the “load side” wiring connection is optional and only used if the GFCI is protecting other outlets. See the GFCI wiring diagrams in this project.

      The troubleshooting steps are:
      * Shutoff the electricity at the circuit breaker.
      * Verify the electricity is Off at the outlet, check each wire with a non-contact voltage detector.
      * Disconnect the outlet wiring.
      * Separate each individual wire and cap it with a wire nut for safety.
      * Turn on the circuit breaker.
      * Check each wire with a non-contact voltage detector to verify which black wire is Hot (energized). That black wire is the “line side” connected to the circuit breaker which supplies power to the outlet.
      * Place a small piece of electricians tape on the line side black wire and the white neutral wire in that cable to flag it as the line side.
      The wires are capped with a wire nut to prevent electrical shock but do take care.
      * Shutoff the circuit breaker.
      * Wire the GFCI outlet per the manufacturer’s instructions, noting the line and load sides.

      Lastly, turn on the circuit breaker and test the Reset/Set buttons for proper operation or better use a GFCI Receptacle Tester.

      • David Krieger October 14, 2016 at 11:17 am - Reply

        I’m a little confused. Paragraph 1, sentence 2 it says,

        ” …because it has “LINE SIDE” (power from the circuit breaker) and a “load side” (downstream protected devices)….”

        Then later the bulleted instructions say that after turning the breaker on:

        “* Check each wire with a non-contact voltage detector to verify which black wire is Hot (energized). That black wire is the “LOAD SIDE” connected to the circuit breaker which supplies power to the outlet….”

        These 2 statements seem to contradict each other. What am I missing. Should the hot the black wire connected to the breaker be connected to the Line side or the Load side of the GFCI?

        Thanks for your patience


        • Bob Jackson October 14, 2016 at 1:06 pm - Reply

          It was typo and should’ve stated “line” side in the following bullet as highlighted below. I’ve also corrected my original comment reply. Thank you for letting me know.

          * Check each wire with a non-contact voltage detector to verify which black wire is Hot (energized). That black wire is the “line side” connected to the circuit breaker which supplies power to the outlet.
          * Place a small piece of electricians tape on the line side black wire and the white neutral wire in that cable to flag it as the line side.

          > Should the hot the black wire connected to the breaker be
          > connected to the Line side or the Load side of the GFCI?
          Connect the black wire coming from the circuit breaker to the line side of the GFCI receptacle. Simple diagram:

          Circuit Breaker — Line Side — GFCI receptacle — Load Side — to lights and other receptacles.

          Things that consume power place a “load” on the circuit, which is why it’s called the load side.

  3. Ed dalton July 10, 2016 at 4:46 pm - Reply

    Thank you very much Bob you are a life and money saver great advice and knowledge !!! :-)

  4. Jen January 16, 2018 at 11:10 pm - Reply

    Hi Bob, I happened upon your site when trying to figure out how to fix a shorted light switch. I was doing a project that one would think was totally innocuous and unrelated to any wires – I was putting in a new deadbolt. Somehow when I took the plate off for the deadbolt hole, sorry don’t know the right terminology, and put the new screws in the plate this somehow must have nicked a wire for my hallway light (didn’t think anything of the fact the screws on the old plate were *off-center). Now my electrician is saying he’ll either have to open the wall (no!) or run another line. Is there a third possibility? Something that might be easier that I might be able to do? Thank you for any help.

    • Bob Jackson January 17, 2018 at 12:07 am - Reply

      What bad luck! The electrician ran the wiring along the king stud and when you drove the 3 inch strike plate screws in it pierced the wire!

      The electrician is correct. I’d choose opening up the drywall because it’s easy to cut and fishing new wire can be a challenge. He’ll install a junction box with a blank cover plate. Junction boxes cannot be concealed per the National Electrical Code, hence a cover plate is required. Paint the cover plate to match the wall and it won’t be that noticeable.

  5. Tom Busler October 6, 2018 at 5:35 pm - Reply

    You said outlets were wired in series. Incorrect! It may look like series because one feeds the next, but black goes to black and white to white That is parallel. If they were in series, everything on the circuit would divide the 120 volts among them. Nothing would get full voltage.
    Also, isn’t 14 gauge wire sort of small for outlets? Usually 14 is used for lights and 12 for outlets.

    • Bob Jackson October 7, 2018 at 1:06 pm - Reply

      Series wiring means power passes through the receptacle break-off fin (a.k.a. tab) that connects the two side terminals; and a fault in an upstream outlet will cause power loss at all down stream outlets. Parallel wiring means current does not pass through the outlet to reach downstream receptacles or other devices. Compare the series vs parallel outlet wiring diagrams. My shorted outlet is wired in series.

      > If they were in series, everything on the circuit
      > would divide the 120 volts among them.
      > Nothing would get full voltage.
      That’s incorrect because power flows across the break-off fin (tab) to reach downstream outlets *and* to whatever is plugged into the receptacle. This forms a *local* parallel circuit within the receptacle (voltage is not divided)… which is not to be confused with multi-receptacle parallel wiring. Also see Electrical Outlets: Side Wire versus Back Wire.

      > isn’t 14 gauge wire sort of small for outlets?
      > Usually 14 is used for lights and 12 for outlets.
      I would require NM-B 12/2 if I were building a new home for 20 AMP outlet and light circuits, but most home builders use 14/2 for 15 AMP circuits because it meets the NEC ampacity requirements, is cheaper and easier to work with because it’s not as stiff as 12/2 cable.

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