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Electrical Outlets: Side Wire versus Back Wire

This article compares the pros and cons of different methods of how to wire an electrical outlet, which are:

  1. Side wiring using the side terminal screws.
  2. Back wiring using the Leviton Quickwire™ push-in feature, colloquially referred to as “backstab”.
  3. Back wiring using the screw-and-clamp system.


Leviton Residential & Industrial Grade Outlets

The two electrical receptacles examined are the Leviton 5230-WCP Residential Grade outlet that sells for around 60 cents and the Leviton 5252-W Industrial Grade (also called “Prograde”) outlet which retails for about $5.50. Both outlets are rated for 15 AMPs and 125 volts.

Leviton Electrical Receptacles: Model 5320-WCP and 5252-W

Don’t be mislead by the “industrial” or “professional” grade label because the Leviton 5252 series are perfectly suitable for residential use, especially in frequently used locations in the home. Which receptacle you choose is mainly a budget issue. Remember, most houses are built by the low bidder!

Electrical Outlet Wiring Methods

The Leviton residential and industrial grade outlets may be wired in three different configurations as illustrated in this photo:

Electrical Outlet Wiring: Back wire, Side wire and Quickwire™ (Backstab)

The Leviton 5230 residential grade outlet (left pair in the photo above) supports:

  • Side wiring via the side screw terminals.
  • Back wiring via the Quickwire™ push-in (screwless push-in terminal), which accepts 14 gauge (NM-B 14/2) wire only. This wiring method is informally known as “backstabbing”.

The Leviton 5252 industrial grade outlet can be:

  • Side wired via the side screw terminals
  • Back wired using the screw and clamp system. Underwriter’s Labs refers to this as a “screw-actuated clamp”.

What’s the difference between the wiring methods and why would anyone care? Let’s take a look!

Side Wiring an Electrical Outlet

To side wire and electrical outlet, the wire is stripped, looped around the side screw and the screw is tightened down on the wire. Side wiring is a secure, reliable and widely employed technique. Side wiring is limited to a single conductor (wire) per screw terminal. Side wiring is the done the same way for both the residential and industrial grade outlets.

Back Wiring:

Differences between Residential and Industrial Grade Outlets

Let’s take a look inside the Leviton residential- and industrial grade electrical outlets for significant differences between the back wiring mechanisms of each:

  • The residential outlet (left side) uses a flat spring clamp to capture a 14 gauge only (NM-B 14/2) wire which is pushed in from the back.
  • The industrial grade outlet (right side) uses a screw-and-clamp to capture a 10 to 14 gauge wire inserted in the back.

Back Wiring Outlets: Leviton Quickwire™ versus Screw & Clamp

Here’s another look at the Quickwire spring tab terminals compared to the industrial grade screw-and-clamp system. The sturdiness of the two is mechanisms is quite obvious!

Leviton Quickwire™ versus Screw & Clamp Electrical Outlet Terminals

The industrial grade outlet is built heavier featuring triple-wipe contacts versus the double-wipe contacts on the residential outlet. The triple-wipe contacts hold a plug more securely and are less prone to wearing out.

Back Wiring using the Leviton Quickwire™ Method

Leviton’s Quickwire push-in method, also known as “backstab”, while being simple and fast to wire, is frequently criticized in the electrical trade as being inferior to side wiring because the flat spring only makes contact with the wire at the edge and allows the wire to rotate and/or wiggle. The movement can build up over time as plugs are inserted and removed from the outlet, weakening the connection and possibly coming loose. Loose connections can cause arcing, excessive heating and interrupt power to the outlet. How many outlets do you have in your house that press inward as you plug something in because the wall box was poorly installed? The outlet isn’t at fault, but shoddy workmanship mounting the wall box aggravates the problem.

Electrical Outlet Back Wiring: Leviton Quickwire™ (backstab) Closeup

The Quickwire outlet has a small rectangular hole in the back to insert the tip of a screw driver to release the wire. I’ve found from personal experience the flat spring noticeably weakens when the wire is released and therefore do not recommend reusing the Quickwire method if the wire is ever removed. Best to side wire the outlet instead. The Quickwire hole on the back only accepts a 14 gauge wire because a thicker 12 gauge wire tends to open the spring clamp, causing loose a connection if a thinner 14 gauge were inserted later.

Why would anyone Quickwire an outlet? It’s simple and fast. If time is money and the electrical contractor is squeezing every penny (remember the job went to the low bidder), then backstabbing the wires would be attractive.

Back Wiring: Leviton Screw & Clamp Method

Back wiring the Leviton 5252 series industrial grade electrical outlet is a whole different ballgame compared to the residential grade Quickwire push-in (backstab) system.

The 5252 industrial grade outlets use a screw-and-clamp mechanism which very securely holds the wire in place and equals the reliability of side wiring. Notice in the closeup below how the screw clamp makes positive contact with the wire with a large conductive surface. The clamp also has serrations to bite into the wire for extra holding power. The wire cannot rotate or wiggle.

Electrical Outlet Back Wiring: Screw and Clamp System Closeup

I prefer back wiring with the screw and clamp system because it’s as secure as side wiring, while being simpler and faster.

In my opinion:

  1. Side wiring is always good.
  2. Quickwire push-in (backstab) should be avoided.
  3. Back wiring with the screw and clamp system is my preference.

Note that all three receptacle wiring methods are listed by Underwriter’s Labs. Check with your local building department if in doubt to comply with all electrical codes.

Hope this helps,
Bob Jackson

Copyright © 2014 HandymanHowTo.com   Reproduction strictly prohibited.

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8 Responses to Electrical Outlets: Side Wire versus Back Wire

  1. R. Work September 19, 2011 at 5:15 pm #

    good article. question. when you back wire an outlet, can you use both the backwire and side wire on the same outlet?

    • Bob Jackson September 20, 2011 at 5:18 pm #

      You can back wire and side wire if it’s a Push-in (backstab) receptacle such as the Leviton 5320 residential grade model because the back wire spring-clamp mechanism is independent of the side screws.

      For a screw & clamp style receptacle such as the Leviton 5252-W Industrial Grade model, the side screw also actuates the back wire clamp. If this receptacle is both back and side wired, the wires are drawn against the copper side plate between the clamp and screw head for a secure connection. I would be careful to only use wire of the same gauge (size) if using both back wire terminals on the same screw to ensure the clamping force is equal across the two back wires. Double check the security of your wiring connections if going with this option.

      See “UL 498 Attachment Plugs and Receptacles” for the technical details.

      If you have so many wires that you need both the side- and back wire connections, consider the parallel wiring method using pigtails about 3/4 ways down the page in this article: Series versus Parallel Electrical Outlet Wiring.

  2. A Harpster October 4, 2011 at 8:43 am #

    Thank you for a most informative article. From it, I was able to identify the existing connection. More importantly, I learned how to get the back-stabbed wires out! Other articles I read told how to put a receptacle in, but not how to remove the back-stabbed wires. I will note that, in this case, the old wires seemed quite firmly set; I could not get them to move although I was trying to. I will use the side screws on the replacement.

  3. Joe Craig November 12, 2011 at 12:44 am #

    Thanks Bob
    You cleared up my confusion over Backwire versus Sidewire nicely.

  4. Celeste January 3, 2014 at 12:29 pm #

    Hey there just wanted to give you a brief heads
    up and let you know a few of the pictures aren’t loading correctly.
    I’m not sure why but I think its a linking issue. I’ve tried it in two
    different internet browsers and both show the same outcome.

  5. Ralph D Jeffords March 9, 2014 at 3:25 pm #

    I just got through troubleshooting a partially dead circuit in my residence. The house was built about 1972 in Centreville VA. Two outlets on this 20 amp circuit were hot and three were dead. In checking the hot outlet closest to a dead one, a neutral wire (obviously the feed-through) popped out of one of the backstab holes and I noted that it had heated up for about 3″ at the end, and that plastic around the backstab hole was disintegrating from the heat. Evidently the wire was either not properly pushed into the backstab hole or the connection disintegrated over time. It seems that all outlets in the house were originally installed “quick and dirty” with the backstab method, even the 20 amp circuits. You mentioned that backstab is intended only for 14 guage (15 amp) circuits. Would you advise replacing all outlets (but especially the 20 amp ones) with sidewired or screw and clamp backwired outlets? By the way, excellent article for the DIYer!

    • Bob Jackson March 9, 2014 at 4:43 pm #

      > Would you advise replacing all outlets (but especially the 20 amp ones) with
      > sidewired or screw and clamp backwired outlets?
      Hi Ralph,
      That’s a two-part question:
      1 – Quality or grade of outlet?
      2 – Sidewire vs backwire?

      Answer #1 – Quality or grade of Electrical Outlet:
      I don’t like the inexpensive residenetial grade outlets that cost as of this writing about 68 cents each due to the lower durability construction. Home builders install these cheap outlets to maximize profit and most people aren’t aware of the difference compared to the professional grade outlet that costs 9 times more at ~$6 per outlet. The 68 cent outlet wears out quickly in high use areas and won’t hold a plug securely.

      The cost savings to hire an electrician to replace an outlet will run $130 to $180 according to this source, so the home builder is passing the total cost of ownership to the homeowner along with risks of arcing/fire due worn out outlets. Consider that if a house has 50 outlets the difference in cost for professional grade outlet is about $265. If an electrician is hired to replace two outlets at $130 each the total is $260 in repairs. That just about erases any cost savings using residential grade (cheap) outlets. With the popularity of consumer electronics outlets are being used much more and there are often not enough outlets where needed. I’m not writing this so much for you Ralph because you’re a conscientious homeowner, but others who read this.

      Answer #2 – Sidewire vs Backwire Screw & Clamp
      Sidewiring by wrapping the wire around the terminal screw in a closed loop and tightening the screw is a secure and durable connection with a large contact area between the wire and outlet. However, it’s slower and requires attention make the loop just right and pinch it closed around the screw with needle nose pliers.

      I prefer the Leviton 5252 professional grade outlet that feature the backwire screw & clamp system. Why? It’s easy to wire and very secure also with a large contact area. It also makes removing the outlet quick and simple by loosening the clamp screw and pulling the wire straight out. Compare to unwiring a sidewired outlet – where you have to bend the wire loop open which stresses the wire. Not good if you’re making wiring rearrangements and need to make a pigtail connection.

      So the main thing is buy the high quality professional grade outlets. I prefer the screw & clamp backwire method but sidewiring is also fine.

      These related projects may be helpful which use the Leviton 5252 Prograde outlet with the backwire screw & clamp method:
      * How to Replace a Worn-Out Electrical Outlet
      * How to Repair a Shorted Electrical Outlet
      * How to Wire an Attic Electrical Outlet and Light

      Sometimes a circuit extension is needed where it’s not possible to fish wire through the walls. Wiremold surface raceways and boxes are a great way to extend power from an existing outlet.

      Centreville, VA – I always look forward to breakfast at Anitas Mexican restaurant when I’m in town. OK it’s actually a mile away in Chantilly.

      Take care,
      Bob

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