The replacement electrical outlet was backwired in series in Part 2
Electrical Outlet Pigtail Wiring Connections
I prefer wiring middle-of-run outlets in parallel with pigtail connections for improved reliability and fault isolation as illustrated in following the wiring diagram. Some local building codes require outlets to be wired in parallel for these reasons.
Electrical Outlet Parallel Wiring Diagram
Rewiring an outlet from series to parallel is straightforward with two short lengths of wire and wire nuts for the hot and neutral pigtail connections. A pigtail connection is always used for middle-of-run ground connections whether wired in series or parallel.
Shut off the Electricity
Be certain to shut off the electricity at the circuit breaker panel as described in Part 1 if you haven’t already done so.
Wiring an Electrical Outlet in Parallel
To demonstrate wiring an outlet in parallel, I disconnected the new Leviton 5252 heavy duty replacement outlet which was backwired in series in Part 2. That’s the neat thing about backwiring – it’s easy to install and disconnect the wires just by loosening the terminal screws.
Electrical Outlet Box Wires
An electrical is wired in parallel with pigtails by:
- Cut a 6″ inch length of black (hot) and white (neutral) wire for the pigtail splices.
- Strip 3/4″ inch of insulation the wires in the wall box and one end of the pigtail splice.
- Matching wire colors, twist the ends of the two black wires coming from the outlet box together with the 6″ black wire splice with lineman’s pliers. Twist the wires in a clockwise direction (right twist) with lineman’s pliers as shown. Secure the wires with a wire nut.
- Repeat the pigtail splice connection for the white (neutral) wires.
Note the bare ground wire is already on a pigtail connection via a metal bonding clamp. If you happen to be running wire to install a new middle-of-run outlet, be certain to make a pigtail connection for the ground wires.
Electrical Outlet Pigtail Wiring
Pigtails wire connections are complete:
Electrical Outlet Pigtail Wiring Connections
Use the strip gauge on the back of the electrical outlet to measure and strip the correct length of wire for the backwire connection.
Electrical Outlet Backwire Strip Gauge
The ground wire is looped around the green ground screw. Tighten the screw really well to secure the connection.
Backwiring an Electrical Outlet in Parallel with Pigtail Connections
Backwire the outlet by:
- Loosening the side screw to expand the internal clamp.
- Insert the black (hot) wire in one of the backwire holes on the side with the brass color screws. Any of the four backwire holes will do. Take care the wire is inside the jaw of the metal clamp.
- With the wire fully inserted, tighten the side screw to clamp the wire in place.
- Insert the white (neutral) in a backwire hole on the side with the silver screws and secure it by tightening the screws as before.
- Check the wires are secure by giving the wires a pull. The wires should be held fast with no “give” or rotation.
Leviton 5252 Heavy Duty Outlet Backwire with Pigtails
Carefully fold the wires into the electrical box using gentle loops. 12 gauge wire is much stiffer than 14 gauge and getting all the wires folded in can take some attention to detail. Make sure the bare ground wire is not touching the side screw terminals.
When the wires are in the box, mount the outlet to the wall box with the two mounting screws.
Mount the Electrical Outlet in the Wall Box
The old outlet wallplate will be replaced with a Leviton Unbreakable Nylon Wallplate for a new and neat appearance.
Leviton Unbreakable Nylon Wallplate
A “GFCI Protected Outlet” sticker is affixed to the wallplate (you get these when you purchase a GFCI outlet – I had some left over from the basement bathroom project).
GFCI Protection Label and Receptacle Tester
I turned on the circuit breaker at the main electrical panel and verified the outlet is correctly wired with the receptacle tester. Everything is correct.
Worn-Out Electrical Outlet Autopsy
The old electrical outlet that was getting worn out with loose plugs is a Leviton Residential Grade Electrical Outlet, Model #: 5320-WCP, UPC Code: 07847715142. These sell for 59 cents at Home Depot and a very common. The outlet served well by bathroom vanity for about 10 years before wearing out. For 59 cents, it’s a testament to the success of mass production and maximum quality at a low price.
A new and old Leviton 5320-WCP receptacles are shown here for comparison. Some pitting around the receptacle face can be seen on the old outlet.
Old and New Leviton Electrical Receptacles Model 5320-WCP
The old receptacle is held together by two metal rivets on the back. I cut off the rivet heads with a Dremel tool and cutoff wheel.
Leviton Residential Electrical Outlet 5320-WCP UPC Code: 07847715142
The main problem with the old receptacle is it wasn’t holding a plug because the U-shaped contacts (yellow arrows) were getting worn out. These U-shaped contacts – also called “wipes” – fatigue and open up over time through repeated use when plugging in appliances.
Signs of Wear on the Leviton Electrical Receptacle Model 5320-WCP
As the contacts open up, the plug becomes loose resulting in a high resistance connection, causing overheating, arcing and corrosion. If the outlet isn’t replaced, the connection can become so bad that constant a constant sizzling or hissing noise is heard from the electrical arcing as happened with that outlet I described in Part 1.
Be safe,
Bob Jackson
Copyright © 2013 HandymanHowTo.com Reproduction strictly prohibited.
Very helpful information on the differences between a series and parallel wiring of electrical outlets. One question when wiring outlets in parallel: Can you add an extra set of pigtails at the outlet where the power comes in from the circuit panel so that you can add additional electrical outlets in two different directions? This question assumes the power from the circuit panel comes in in what would be the middle of you series of outlets. Thank you.
Bob, great article. The pictures helped out. One question though. I replaced an outlet that was a middle of the run outlet wired in series. When I installed the new outlet in parallel, that outlet worked fine but those down stream did not. Any idea why?
You can tie in a new run of NM-B cable using the existing pigtails with 3 appropriately sized wire nuts in the outlet box, however the problem is the volume of a single gang outlet box with typical dimensions of 3″ x 2″ x 2.75″ (= 16.5 cubic inches total volume) will be the box is too small for to hold everything in violation of the National Electrical Code. The purpose of the “box fill calculations” is to prevent overcrowded and broken wires that could be a fire hazard.
The correct approach is to remove the single gang box and install a double gang box. If retrofitting, cut a larger hole in the drywall to fit an “old work” double gang box. Use a cover plate that’s half blank (solid face) with an outlet profile on the side.
Keep in mind that while there’s not a specific limit to the number of outlets on a branch circuit, the NEC says the total load should be no more than 80% of the circuit breaker rating. So you may want to total up the current loads in AMPs for the TV, lamps, computers, portable electric heater, etc. to see what will be expected for the total load. If greater than 80% of the circuit breaker rating, consider pulling a new branch circuit for the receptacles to a dedicated circuit breaker.
You’ll have to troubleshoot the wiring to figure out what’s wrong. You’ll need a non-contact voltage tester, some masking tape and a pen.
1) Turn off the power at circuit breaker serving the receptacle circuit.
2) Verify the receptacle is dead with the voltage tester.
3) Remove and unwire the receptacle. Set it on the counter out of the way.
4) Disconnect and separate the black (hot) and white (neutral) wires.
5) Leave the ground wires connected for safety’s sake.
6) You should now have two black and two white wires exposed and separated from the outlet box.
7) Turn on the power at the circuit breaker.
8 ) Very carefully verify which of the two black (hot) wires is energized with electricity with the voltage detector.
Best to keep one hand in your pocket while doing this.
Only one black wire should be energized. Remember which black wire is hot.
9) Check if either of the white (neutral) wires is energized with the voltage detector – neither should be live.
10) Turn off the electricity at the circuit breaker.
11) Label the one black wire that was energized with a small piece of masking tape marked “line side”.
12) Wire nut together the two black wires coming from the outlet box.
13) Wire nut together the two white wires coming from the outlet box.
14) Turn on the circuit breaker.
15) Check if the downstream outlets have power.
16) No power in the downstream outlets? You have a broken wire in one of leads coming from the outlet box. Is there a sharp kink that would indicate a break?
17) Got power in the downstream outlets? You probably had a bad wire nut connection in your pigtail. Perhaps something came loose when you folded the wires in the wall box?
18) Turn off the power at the circuit breaker.
19) Wire the receptacle in parallel with the pigtail in the usual way.
20) Leave the receptacle hanging out of the wall box.
21) Turn on the power.
22) Check the wires for voltage with the voltage detector. Are the downstream outlets energized? Good.
23) Turn off the power.
24) Carefully fold the wires into the outlet box and remount the receptacle.
25) Turn on the power and recheck the downstream receptacles for power.
Let me know what you find. If you’re still having trouble, pictures would be helpful.
had a receptacle sizzle ,heard it in the other room, nightlight was plugged in,jiggled light and saw sparks ,felt of socket and it was warm, turned off breaker.whoa what a fire hazzard. replaced socket(burnt just a bit) and turned power back on ,checked to see if wirred correctly by tester, if you don’t have one i reccomend getting one. the one i have has lights on it and tells you by lighting up if wired correctly or incorrectly. by checking out the bad socket it looks like by useing so many years it had worn out receptors and would not make a good connection. i googled this site and this confirmed my inspection. very good article. thanks for showing this
Sorry for the NOOB question: Our house electrical outlets are wired in series. I would like to install a run of Pass & Seymours Combination Nightlight/Outlets (TM8HWL-TRWCC6). Basically, an oulet with a built-in nightlight. This outlet only has three terminals (ground, hot, and neutral). Therefore, necessitating that I wire this as a Parallel. Here is the NOOB question: Do I need to convert ALL (100%) of the middle-of-run outlets as Parallel? Can I have a mix of series and parallel? Basically down our main hallway, I would like to replace all of the outlets in the hallway with Combination Nightlight/outlets so that I can have a night-lighted hallway. I am not sure where the series begins or ends and am concerned that I am doing something goofy or inappropriate if I parallel (pigtail) some of the outlets and leave the rest as series.
> Can I have a mix of series and parallel?
Yes.
> Do I need to convert ALL (100%) of the middle-of-run outlets as Parallel?
You do not need to convert all the outlets, just the ones that will be replaced with the combo night light/outlet.
Remove the existing outlet that is wired in series, then wire the combo night light/outlet in parallel with a pigtail.
An electrical heater was plugged in to an end of the run outlet. the heater blew up and now the two rooms and part of the basement has no power. My beaker tripped but wont stay on indicating theres a problem/short somewhere. my question is how do i pinpoint the problem? or what the problem is? i understand i have to locate the first outlet in the run but how do i locate it. or is it possible that the problem is not an outlet at all?. i dont even know where to start. at this time i really cant afford to hire an electrician.
Hi Nathan,
I recently had a similar problem to yours, see this project: How to Repair a Shorted Electrical Outlet.
Have you removed the outlet that the electric space heater was plugged into, inspected the wiring and replaced the outlet? My bet is the outlet is shorted, which is why the circuit breaker keeps tripping (which is good because the circuit breaker is doing it’s job to protect you.)
Be certain circuit breaker is in the full Off position before working on the wiring.
Let me know if replacing the outlet and repairing the charred wiring fixes the problem.