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Proper routing and support of electrical wire (C) Carson Dunlop AssociatesElectrical Wire Routing & Protection
How to route & locate wires for an electrical plug outlet or wall plug

How & where to route electrical wires when hooking up an electrical receptacle or wall plug or electrical outlet.

This article series describes how to choose, locate, and wire an electrical receptacle in a home.

Electrical receptacles (also called electrical outlets or "plugs" or "sockets") are simple devices that are easy to install, but there are details to get right if you want to be safe.

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

Routing, Securing & Protecting Electrical Wires for a New Receptacle

Proper routing and support of electrical wire (C) Carson Dunlop Associates Proper routing of electric wires in metal studs (C) Carson Dunlop Associates

[Click to enlarge any image]

The electrical circuit wire must be properly routed and secured between the electrical panel and the receptacle location, and must be properly secured at the junction box that is to hold the electrical receptacle.

We secure wires at intervals specified by the electrical code so that it doesn't sag, hang, pull on itself, and become damaged or unsafe. The two sketches below, courtesy of Carson Dunlop Associates, show examples of routing electrical circuit wires through a wood stud wall and through a wall supported by metal studs.

Nail Stop Simpson Strong Tie NS2 16Ga © D Friedman at InspectApedia.com The electrical circuit wire must be protected from damage. We don't route electrical wires where they can be punctured by someone driving a nail into a wall to hang a picture.

Using Nail Stops to Protect Wiring & Pipes in Walls

Wires running in walls anywhere from floor level to seven feet above the floor (U.S.) or five feet above the floor (Canada) must be protected from nails driven through walls. Our photo (left) illustrates a 6-inch NS-2 Nail Stop produced by Simpson Strong-Tie. Simpson Strong-Tie describes these as Protecting Shield Plate Nail Stoppers.

We are showing the side of the nail-stop that will be in contact with the stud surface when it it tapped into place, providing 5 3/8" of 16-gauge steel that will protect electrical wiring (or plumbing pipes) from punctures by nails or screws driven into the wall when this nail stop has been placed on a wall stud over the point through which an electrical wire (or pipe -

see CONDENSATE DRAINS, CODES) has been passed.

Nail stops by Simpson Strong-Tie are made of 16-gauge steel, include sharpened protrusions that allow the plate to be tapped into place on stud surfaces, and are sold in 1 1/2" or 5-inch widths and in lengths ranging from 2 1'2" to 16 5/16". The most commonly-seen nail stop we encounter is the NS1 3-inch model.

Nail stops prevent penetration of fasteners into wiring or piping.

They are 16 gauge steel to meet the protection requirements of the code and feature a galvanized coating. Install with prongs or 8d common nails.[6]

Simpson Strong-Tie provides a Code Compliant Repair and Protection Guide that describes the company's range of protective and reinforcing steel devices to comply with the various building code requirements to protect wiring and plumbing from nail and screw fastener damage.

Electrical Wire Clearances from Ducts & Pipes

We also don't route wires too close to places where the wires can be damaged by heat from a heating appliance or chimney, flooded, etc. as you'll see depicted in the two Carson Dunlop Associates sketches below. Thanks to Steve for pointing out erroneous illustration link details, now fixed.

Proper routing of electric wires in metal studs (C) Carson Dunlop Associates Proper routing and support of electrical wire (C) Carson Dunlop Associates


Color coding of wires to properly connect an electrical outlet (C) Carson Dunlop Associates

The illustration at left shows the typical wiring of an electrical outlet or "receptacle", courtesy of Carson Dunlop Associates.

Watch out: Electrical components in a building can easily cause an electrical shock, burn, or even death. 

Even when a hot line switch is off, one terminal on the switch is still connected to the power source.

Before doing any work on the switch, the power source must be turned off by setting a circuit breaker to OFF or removing a fuse.

See SAFETY for ELECTRICAL INSPECTORS

and ELECTRICAL WIRING BOOKS & GUIDES

Routing Electrical Wiring Through Metal Studs

Reader Question: NMC cable pulled through metal studs without proper protection

Having a hard time with seller who framed the basement with metal studs, and pulled ROMEX through with no grommets or bushings.

Tried to explain that that Metal studs are SHARP and will eventually cut through the romex and short it (POW !), or make the studs live (ouch) I will trade pictures with you if you have some that will go with these.

These photographs (below) are from the inspection. - B.S., Professional home inspector, 7/27/2014

Unprotected NMC wiring passing through a metal stud violates electrical code (C) InspectApedia Bob Sisson Unprotected NMC wiring passing through a metal stud violates electrical code (C) InspectApedia Bob Sisson

Reply:

Greenlee wiring bushings for metal studs PN 712A1000 - www.greenlee.com You are correct that wiring passing through metal studs require protection against damage.

There are simple plastic snap-in wiring grommets or "bushings" that offer that protection and that would have been easy to install at the time of wiring and that can doubtless be retrofit now though if the installer has to cut the bushings to insert them around the existing wiring s/he will need to check with the acceptability of that bushing modification by callling the local electrical inspector for the jurisdiction.

Carson Dunlop Associates sketch of wiring passing through a metal stud (image, used with permision) just above in this article discusses this very topic.

The photo at left, courtesy Greenlee Corporation (www.greenlee.com) illustrates a plastic bushing PN 712A-1000 designed to protect wiring where it passes through metal studs.

Wiring through metal studs is a very common procedure as we know. In addition to using the larger holes shown in your photos, there is a punching tool (a metal stud punch) and plastic grommets to fit the punched holes so that wires can be run exactly where needed.

I'll post your photos along with images of the proper plastic bushings and send you the link.

U.S. Electrical Code for Wiring NMC through Metal Studs

Meanwhile, if we are reduced to having to cite code to tell some goofus what she or he ought to have known and done in the first place, see these NEC sections:

NEC 334.17 Through or Parallel to Framing Members.

Types NM, NMC, or NMS cable shall be protected in accordance with 300.4 where installed through or parallel to framing members.

Grommets used as required in 300.4(B)(1) shall remain in place and be listed for the purpose of cable protection.

and see

NEC 300.4(B) Nonmetallic-Sheathed Cables and Electrical Nonmetallic Tubing Through Metal Framing Members.

(1) Nonmetallic-Sheathed Cable. In both exposed and concealed locations where nonmetallic-sheathed cables pass through either factory- or field-punched, cut, or drilled slots or holes in metal members, the cable shall be protected by listed bushings or listed grommets covering all metal edges that are securely fastened in the opening prior to installation of the cable.

Canadian Electrical Code for Wiring NMC through Metal Studs

Canadian Inspectors needing code citations for protection of non-metallic-sheathed wiring will want to see the 12-19-11 Ontario Electrical Safety Code Bulletin

Rule 12-516(2) permits the use of non-metallic-sheathed cable with metal stud construction.

Where NMSC is used in metal stud construction the following are installation requirements:

Thanks to Mike Holt for help with this topic. https://forums.mikeholt.com/

Sources of wiring protection, grommets, bushings for metal studs

1 5/8-inch plastic grommets for routing electrical wires through metal studs - from Dietrich - cited at InspectApedia.com

Shown here: red plastic metal bushings or grommets for wiring through metal studs, provided by Clark Dietrich Co. cited below.

[Click to enlarge any image]

Greenlee metal stud bushings or grommets cited & discussed at InspectApedia.com

Tyco Electronics metal stud bushings sold in round & square shapes, www.te.comIllustration: red round and square plastic grommets for use in routing electrical wiring through metal studs, provided by Tyco, cited below.

[Click to enlarge any image]


Can be used with any type of wire. Use these bushings to comply with paragraph 300-4b(1) of the 2005 NEC code.

 

 

Electrical Wiring Routing & Protection References

Simpson nail plates, guards & reinfocements for wood framing - cited & discussed at InspectApedia.com

Illustration: Nail plates, guards, reinforcements in wood framing, from Simpson Strong-Tie's 2020 Code Compliant Repair & Protection Guide [PDF] cited below. [Click to enlarge any image]

Unsafe & Improper Electrical Wire Material & Routing

Zip Cord or Extension Cord or surface-notched wires in plaster or drywall

Electrical receptacle and zipcord wiring © D Friedman at InspectApedia.com Here is an example of improper and unsafe electrical wiring: lamp cord or "zip cord" has been routed through the building wall.

Our photo (left) shows an electrical receptacle mounted just about 2" above the finished floor - which is ok except for the ADA requirements, but that zip cord wiring that is run into the wall is improper, unsafe, and a fire hazard.

 




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Reader Comments, Questions & Answers About The Article Above

Below you will find questions and answers previously posted on this page at its page bottom reader comment box.

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

Question: ok to notch an electrical wire into the plaster wall surface?

2020/04/15

I have a new TV that I'm framing, so I can't have the wires exposed.

The problem is that I have a plaster and lath wall that doesn't really have any space for me to run cables behind it. In fact, the wall between my apartment and my neighbor's is a mere 2.5" thick.

So I had an idea. I would simply cut a 1" deep channel in the wall as a recess area for a square raceway, this would house the media and power cable till it gets to the media cabinet only 1.5 ft below it.

It'll be a short race, but is that up to code? - Anonymous by private email

Reply: Don't bury electrical wire hidden in a wall surface. Here is a better approach

No, not in my opinion, not unless you either provide a nail-proof metal shield over the entire passage or use steel conduit to keep someone from punching a nail through the wiring in the future.

Aside from violating electrial codes, in a more lay-person explanation, if you bury an elecrical wire just below the surface in a channel notched into plaster or drywall, then smooth it over so the wall looks nice again, the risk is that someone else, in the future, hangs a photo or something else on the wall by driving a nail or screw right through the wire. The risk then is fire or shock or worse.

But before you go to that trouble I'd consider snaking a wire through the wall cavity. Working on older plaster-lath homes I found that was pretty easy, especially on interior partition walls that are not blocked by insulation. For a case like yours, bringing power to a recessed wall cavity, you have to cut the wall open at that location anyhow.

So I might try snaking a wire down to the bottom of the wall.

There I pull off the wall-floor baseboard trim, open the wall as needed to route my power wire to a source, then put back the baseboard.

I've then avoided cutting and fooling with the plaster and my wire is safely inside the wall cavity where it is not so much at risk of a puncture by some future nail or screw driven innocently into the wall.

An alternative would be to route steel conduit in the wall surface and plaster over that, provided your electrical inspector will approve that installation.

Question: where to buy smaller 1 5/8-inch grommets for metal stud wiring?

1 5/8-inch plastic grommets for routing electrical wires through metal studs - from Dietrich - cited at InspectApedia.com

(Oct 7, 2017) E said:

I'm looking for grommets that will fit 1-5/8 metal framing stud. Anyone know of a website I can find smaller gromments?

Reply:

E:

Snap-in plastic grommets for use in metal studs and that will fit a 1 5/8" opening in the stud are widely available from electrical suppliers.

Shown here are red plastic 1 5/8" metal stud grommets made by Clark Dietrich www.clarkdietrich.com

Question: where to get square grommets for metal studs

(July 17, 2017) Kevin W said:

When searching for Greenlee 712A100, I can only find the circular grommets. Is there a separate part number, specifically for the square grommets?

thanks in advance,
Kevin

Reply: Tyco and others

Kevin,

On the page above you will see square grommets for wiring through metal studs, produced by Tyco (and others).

All of the Greenlee grommets (plastic metal stud bushings) I found as well as grommet opening punches for use on metal studs (to run wiring) were round in shape.

I was unable to find the exact part you specified.

If you can send me photos of it and any packaging I'll research further. Use the page bottom CONTACT link


...

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