How To Run Romex Wiring on Stud & Joist Framing
We recently finished running romex wiring to 20 receptacles and 4 radiant heating zones in the basement. The job required about 500 ft. of 14 guage, 2-wire Romex for the outlets, and 50 ft. of 12 guage, 2-wire Romex for the heating zones. I’m not an electrician, so I asked a relative who is a licensed electrician in our county to supervise and check my work. In addition to supervising, he makes the final connections to the main electrical box.
Most of the work installing new circuits is spent between two activities: running and securing the romex throughout the framing structure, and wiring the receptacles and fixtures at the electrical box endpoints. This post is focused on the running and securing part of the job.
Through the whole process, I found Stanley’s Home Wiring Guide to be extremely helpful in ensuring I got everything right. Here’s a few quick tips from my experience that will likely be helpful to another do-it-yourself electrician who’s framing their basement. Remember, electrical codes vary by locale. You should always consult with a licensed professional before undertaking an electrical project.
- Measure twice, cut once. This old adage is crucial to saving money on electric work. Copper prices at all-time-highs – a cut wire that’s too short to connect to the proper location in the main panel and the target electrical box renders the Romex wire unusable for that run. If you make this mistake, hopefully you can use the mis-cut for other areas. Of course, mis-cuts usually add up to many small, unusable pieces of romex that are only good to a recycler.
- Don’t Splice Wires in Walls. Spliced wires outside of electrical boxes are dangerous. They can pull apart while you’re running the wire, or later when the electrical work is being serviced.
- All Electrical Boxes Must be Surface Accessible. You cannot install a box “somewhere in the wall” that isn’t easily accessible from the finished room. All electrical boxes must be accessible from a faceplate in the finished room.
- Secure Wires Every 24″ or less. Always use fasteners that are approved for the guage and number of wires you are securing. Multiple wires can be secured together using a large nail-in staple. If a wire is cut or knicked by a fastener, you MUST re-run the segment. A knicked wire will cause the wire to heat up at the thinnest point. Running the wire through holes in studs/joists counts as securing the wire for that segment.
- Keep Wires Atleast 1.25″ Away from the Surface of Studs/Joists. Cutting holes in joists to run wire is fine as long as it doesn’t effect the structual integrity of the building. Remember, a standard 2×4 stud is 3.5″ wide. You should drill holes in the middle 1″ of the 2×4 to avoid requiring nail plates.
- Add Nail Plates Where Wire is Close to the Surface. If you can’t avoid running Romex close to the surface, you must protect the surface with an approved nailplate. Since nail plates can cause drywall to stick out over the framing member, you may want to counter-sink the nail plate by slightly grinding/sanding out the stud or joist where the nail plate will be used.
What do you think? Did I miss something in my list? Was this post helpful to you?
May 22nd, 2008 at 8:21 pm
The Stanley Home Wiring Guide is a MUST have for home owners. I remember using that when we bought our first home and it was a huge source of information and guidance.
May 24th, 2008 at 12:15 am
The B&D book is another good reference.
I’d add two common DIY code-related mistakes to your list:
~ If you’re using plastic boxes, the tabs where the wires go in are NOT supposed to be taken off in the same way that you knock out a hole in a metal box; they’re supposed to stay in place and serve as your wire clamp.
~ Be careful to not take off too much of the insulation/ sheathing, since it has to extend into the box by a half-inch or so. If it doesn’t quite reach inside the box, it’s not to code.
(This one courtesy of the previous owners of my house who put in the bathroom light with almost a foot of the sheathing removed outside of the box, which means that I now have to strip out a huge section of the drywall in my bathroom ceiling to bring it up to code if I don’t want to add in an ugly j-box. Oy!)
Several safety additions:
~ Check the power every. single. time. Never trust that “no one would have turned that breaker back on while I was eating lunch.” Never trust that all the wires in a box are on the same circuit if they’re not connected together. Never even trust that the top plug in a receptacle is on the same circuit as the bottom one (I got a nasty shock from that mistake!).
~ When you turn a breaker off, tape it down to ensure that anyone else looking into the panel knows that it’s supposed to stay off. And if you’re working on the wiring for a switched light, tape the switch down even though you’ve turned off the breaker at the panel.
~ Take the time to take off your rings and put on rubber-soled shoes if you’re going to do electrical work.
Two convenience additions:
~ Do yourself a favor and grab a permanent marker and write (in the box, on a wire, on the back of the plate, on some special wire labels, somewhere!!) which breaker controls the wires in that box. Even if you have a very clearly marked panel, it will cut down on the time needed to search for the right breaker.
~ Also, mark where each wire comes from/goes to, so that you can trace the wiring path long after you’ve misplace the diagram that you swore you’d always keep handy.
And finally, one frivolous addition:
~ If you have a wall open for any reason, grab some permanent markers and let friends, family and especially kids go to town on whatever’s behind the wall - draw pictures, write your names, write something about the renovation you’re doing, stick in some photos or news papers, create your own little time capsule. Old house owners generally LOVE finding hidden things behind their walls, and you may totally make someone’s day 50+ years from now when they need to open up that same wall that you’re putting up now.