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Running the Wires for Structured Wiring

   So you have laid out your wiring plan, have all your supplies, and are ready to wire your house. This guide tells you what you need to know to do the actual wiring. This guide will start with some basic rules, then has some pictures on properly running the wires, and also some pictures that will help you locate where ductwork will be run so that you can avoid it. Finally, there is the "Don't do this" section of common mistakes to avoid.

   Start by running the longest wires first. The reason for this is if you have 30' left over in your spool, you might still be able to use it somewhere. If you run the shortest runs first, then you will have more waste.

   Start each wire upstairs and pull it through to the basement. This way, you do not need to use a ladder to push the wire up between floors.

   Do not put two electrical boxes on opposite sides of the same stud. Doing this requires the drywaller to cut two holes only 1 1/2 inches apart. This is difficult and usually results in a broken piece of drywall that will just be patched later. You should also not put an electrical box right in the corner of a room for the same room.

   You will mount your electrical boxes at the same height that the builder's electrician's boxes. This will be around 12-16" from the floor to the bottom of the box. Sometimes, a builder will use their hammer height as a standard for mounting boxes. I used a 12" T-Square to measure the height of mine.

   You may want to mount all of the electrical boxes first just so you know where you will be running the wires. You can mount the boxes and write on the stud what wires are needed using a sharpie. Then you can get to the business of running wires without having to go back and keep looking at your wiring plan.

   Run all of the wires next. Save the stapling of the wires and placing the wires in the electrical box for the end. For the first one or two wire runs you may want to ignore this rule and install the boxes and staple the wires down before you cut the wire just to make sure you understand how much slack you will need. You should also leave at least one foot of extra wire at each end just in case you need to move things around later.

   Before drilling any holes, make sure to look at what is on the other side of the wall/floor. You don't want to drill through any electrical wires, ductwork, or water pipes...

   Do not run wires parallel to any power lines. It is OK to cross a power wire at a 90 degree angle. Power is usually run around the edges of the basement, so run your wires internally along a floor joist. If you need to run your wires perpendicular to a floor joist, try to do it along a duct or I beam. That way if you finish your basement later, these wires wont interfere with a drywall ceiling.

   Run the wires vertically from floor ceiling and then along the floor joists. Do not run a wire horizontally in the middle of a wall. Doing so increases the chance that someone will put a nail through it. Try to keep the wire as close to the stud as possible. This is especially true for an exterior wall where insulation will be installed.

   After running the wires, make sure to label each end (using stickers or writing on the wire with a felt tip marker) and make a note of the label for the wire and its location. I use a letter to represent each electrical box, and then a number for each wire in the box. For example: I will label the electrical box behind the entertainment center in the family room as "A". Each wire in the box gets a number "1", "2", "3"... At the other end at the wiring panel I label the wires "A1", "A2", "A3"...

   After the wires are run, you need to staple them down. Stapling keeps the wires in place so that they don't come out of the electrical boxes. It also holds them up and out of the way of the drywallers and so that they don't hang down in the ceiling. You should always staple the wire right before it enters an electrical box, and also right after it comes through the hole in the floor. When running a wire along a stud, try to keep the wire centered in the stud. That reduces the chance that a nail will go through the wire from either end. For many wires, you can nail the staple into the joist/stud and the use a wire tie to attach the wires to that staple. This method also ensures that the staples cannot damage the wire.

   If the end of the wire does not terminate in an electrical box, then you will need to measure the location of the wire. Measure from the closest corner of the room. Do not measure from a window. Also record if the wire is on the left or right side of the stud. For example, if the wire is attached to the left side of a stud, and you record that the wire is 90" away from the wall, when looking for that wire later your stud finder will tell you that there is a stud at 90". You won't know which side of the stud to cut the drywall on. For complicated runs, you may even want to use a digital camera to record the location of wires. Also remember to add or subtract 3/4" from the measurement to account for the thickness of the drywall where you will start your measurement.

   After running the wires through the electrical box, be sure to shove all of the wires in the box. Drywallers want to work fast, and any wires sticking out of the box may just get drywalled over. They could also get cut as the hole is cut for the electrical box. The builders will probably not take the time to place the wires in the box themselves. Also, if the wires stick out of the box or are very close to the front of the box then they will get covered in paint and may cover up your labeling or the labels could get torn off.

   Some people run the wires straight through the box. The wire coming through the bottom of the box is stapled tight to the stud. The wire then passes through the top of the box and is loosely held to the stud with another staple. When finishing the installation, you can pull the end of the wire back into the box. The loose staple only holds it in place for the drywallers. I don't recommend this method because the the builder should be insulating each electrical box (as long as it is on an exterior wall) with expanding foam so that you can't get cold air coming through the box. If the builder sprays Great Stuff into the back of each electrical box, then you wont be able to get the end of that wire back into the box. I also don't like using backless electrical boxes for the same reason.

   Wait to install the wall plates and in-wall speakers until the drywall has been installed and painted. You can choose to terminate each wire properly as the builder is still working on the home or you can wait until you move in. If you finish the installation up front, then there is a chance that the town's appraiser will see it and you could affect your home's appraised value and tax bill. For my home, I used blank wall plates during the building phase and then finished the work later. Local codes will probably require that you cover all exposed electrical boxes even if there isn't any power in the box so leaving electrical boxes open is not an option.

   When running wires before the HVAC (Heating, Ventilation, & Air Condition) installers have done their work, you need to run your wires without interfering with what they need to do. The HVAC installers will install ducts that deliver the hot or cold air to the home, and returns that feed the air back into the furnace. Vents are usually installed on the floor or low on the wall under a window. The ductwork for a second floor vent is run vertically on an interior wall, and then across the floor joists for the second floor. Returns are usually near the ceiling on an interior wall. Since air loss isn't an issue on a return, the installers don't use ductwork for returns. They will use walls, studs, floor joists... as their duct. Ducts for vents should be avoided inside walls. Returns in the basement should be avoided between the floor joists. There are some specific examples with drawings and pictures below.


   Wire run drawing

Running Wires to the first and second floor outlets

  When running wires from the basement to outlets on the first or second floor, be sure to avoid the flue and any HVAC ducts. When possible, avoid running wires in the ceiling against the joists (red wire above). Instead, try to get right under the outlet from the basement and then run it straight up (green wire above). The same goes for in-ceiling speakers. Avoid drilling through the joists if you can. You may also want to review our guide on wiring existing homes for more examples.


   How to run the wires - Here are some sample pictures of what your wiring should look like.

   Click on any image to see a larger version.

Electrical BoxWhen installing an electrical box, drill a hole in the floor between the studs on the same side as the electrical box. Staple down the wire right above the hole and right under the electrical box. Drill multiple holes if there are many wires. Just be sure not to drill through the wires from the previous hole.
An extra staple would be required if this box was higher off the floor. Both the box and the hole in the floor are insulated with expanding foam.
The wire is coiled in the box so it will not interfere with the drywall.
Separate Wires along JoistThe builder will usually run wires around the outside of the house. Run your wires internally and away from any power wire. Run the wires along the joist. Any wires that run under a joist perpendicular to it could cause problems later if you finish your basement. It can interfere when installing a ceiling.
Perpendicular to PowerWhen your wires are near power, it should be perpendicular to the power wire.
Looped Wire/SlackWhen you do need to run wires near a duct or plumbing, be sure to leave some slack so that the other installers can move your wire if necessary. Don't assume that you know exactly where the duct will be run.
Slack was left in this wire to make room for the ductwork that was to be installed later. This shows how important it is to know where the ductwork will be installed.
FireplaceThis wiring is for a flat panel TV above a fireplace. There is an electrical outlet and a separate outlet for the audio/video.
FireplaceFrom this angle, you can see the audio/video wires run from above the TV to an area next to the fireplace where the stereo components will be located there. Maybe there will be built-in bookshelves on either side of the fireplace to hold the components.
Wire panelRun all of the wires to a central location in the basement/wiring closet. I run mine near the electrical box, but a couple of feet away from it. Leave enough wire so that you can move your wiring panel a couple feet in any direction. Loop the wire and use wire ties to keep it together so it doesn't rest on the floor.


   How to avoid ductwork, electrical, plumbing... - As you are installing your wires it is important to be able to identify what the other installers are doing and where they are doing it. Usually, the HVAC installers will first rough out their ductwork so that the plumbers, electricians... will know where the ducts will be. The ducts wont actually be installed, but the location and shape of certain holes should tell you everything you need to know.

   Click on any image to see a larger version.

Floor VentThis is a hole for your standard floor vent. Floor vents are usually at the edge of the home and are placed under windows. There will be a duct running from this hole to the furnace.
Floor VentSometimes, the builders will take the rectangular piece of floor that was removed for the vent and nail it above the hole on an angle. This is done so that no one accidentally steps in the hole and breaks an ankle. These holes are no different than any other floor vent.
Another way of covering a floor vent.
Bathroom VentThis could be either a return or a vent. If it is in a bathroom, then this will be a vent. Returns should be placed high on the wall, but if that is not possible (in a room that is all windows), this could be a return.
Kitchen VentMany times there is no room in a kitchen to place a vent, so it is intalled under the kitchen sink. Before the cabinetry is installed, this will just be a hole in the floor with a piece of wood covering the opening.
Floor VentYou can identify a vent in a floor from below the floor. The HVAC crew will start by installing this piece of ductwork at the hole.
Floor VentDucts are run vertically at the inside of the home, so the next step is to run the ductwork horizontally between the floor joists to an interior wall.
DuctIn this example, you can see the duct come from the first floor basement, through an interior wall, and then up through the 2nd floor at the exterior of the home.
Duct  DuctHere, the duct work has only been roughed out, but you can tell from the location of the holes were the duct work will be. Then, you can keep your wires away from it. The second image on the right has a line indicating where the ductwork will be.
ReturnIf you see a sheet metal frame like this at the top of a wall, then it is a return. This metal indicates to the drywallers where to cut the hole for the return, and the metal will also hold the screws for the vent cover.
This is a different style of return frame that has 4 sides instead of 3.
This is what the return will look like when complete.
VentBelow the return will be a hole in the floor. This will be on an interior wall. If there is a metal frame at the top of the wall, then that tells you this is a return and not a second floor.
Sometimes the builder will frame out the bottom of the wall in metal. This can prevent drywall cracks if someone kicks the wall.
Return  ReturnPictures of 2 different returns that show the hole in the floor and the frame for the return.
ReturnThis is how the return is framed in the basement. The floor joists act as the sides of the duct, and the floor is the top of the duct. Sheet metal is added to the bottom of the joist as the bottom of the duct. You cannot run wires through this area, so it is important to be able to determine where the returns will be.
VentHere, there are 2 adjacent holes in the interior of the home. One of them already has a roughed in duct. Either the builder didn't finish, or the right hole is a second floor duct, and the left hole is a return.
FlueHere are some other items you should be familiar with. The left tube is the flue. This will be directly above the water heater or furnace and can get very hot. The flue will run straight up through the roof. Next to that is a pre-installed radon tube in case radon gases start building up in the basement. This option is not found in most homes. The right most tube is a future-tube upgrade. The builder can install this tube so that the homeowner can run wires from the basement to the attic at a later time.
Future TubeThis is a closer view of the future tube. Each end of the future tube is capped so that it doesn't act as a chimney in case of a fire.
Central VacThis is what a central vacuum system looks like before the drywall is installed.
InsulationAny holes drilled through floors or any electrical boxes on exterior walls should be insulated with caulk or expanding foam.


   Here are some examples of what not to do. - There are a couple of new housing developments around where I live, and unfortunately it was too easy to find many examples of what not to do.

   Click on any image to see a larger version.

Adjacent Electrical BoxesHere's what happens to your drywall when you try to put two electrical boxes on either side of the same stud. The builder will probably do a good job taping, but they usually cover up part of the box opening in the process. When you go back to square out the opening later, the spackle will break off in large chunks.
Mess in the BasementDon't leave the wires in a mess in the basement, especially if the floor of the basement hasn't been poured yet.
Open Electrical BoxOpen back electrical boxes cannot be sealed to prevent cold air from coming in through the outlets (although this box is on an interior wall, so it wouldn't be sealed anyway). Also, the wires coming out of this box need to be cleaned up before the drywallers show up.
Wire in wallI always prefer running wires through the floor/ceiling until I get above/under the outlet. Then I run the wire along side a stud, centered on the stud to reduce the chance someone puts a nail through it from either side, and stapled to the stud to keep in in place. In this example, no one would expect an electrical wire to be running through the wall at that height, so it can be an electrical hazard. This wire would also need to be moved if you were to ever add an extension to your home or add a new door.
Here is another instance of wires through a wall that also happened to be a return. Each hole had to be insulated with expanding foam.
Medicine CabinetHere's another horizontal wire through a wall where the electrician didn't realize that a medicine cabinet was going to be installed. This wire may prevent the cabinet from being pushed back all the way, and if the back of the medicine cabinet has sharp edges it could cut through the wire.
Duct with wiresHere's some wires running through a hole that was cut for ductwork. This duct is round, so there is a chance that it is the main flue, which would run much hotter than the other ducts. Building codes require that no wiring come in contact with the flue. Typically, they must be 1" away from the flue (from top to bottom). Plenum wires may be rated to handle this heat, but why take the chance. Also, when heating systems turn on the ductwork may flex a bit as the fans kick in. If the duct is touching the wires, then the wires may move against the wood floor and metal duct which may cause them to fray. There is plenty of room to run wiring, so just stay away from the ductwork.
Vent hole with wiresHere is more wires running in a hole for ductwork. This is an interior wall, so it is either for a second floor vent or a return. If this is a return, then the wires will get boxed in the duct.
ReturnHere is an example of wires running through a return between two floor joists as seen from the basement. While most ducts are tubes that you can work around, the return is usually a piece of sheet metal mounted between two floor joists. The floor joists and the floor make up 3 sides of the duct. The installers will put a piece of wood or metal at the end of this duct. Running wires through this area forces the installer to do some ugly work to go around the wiring, and the wires aren't easily accessible later.
Electrical BoxThe wire in this electrical box passes right through the box. This is done so that the wire doesn't get covered in spackle or paint. The bottom staple is only loosely holding the wire so that it can be pulled through later. If the builder insulates this box with caulk or expanding foam, you will not be able to pull the wire back through.


   Some final warnings and special cases.

Wire Staple With Zip TieWire Staple with Zip TieAny time you are attaching a wire to a stud or joist, use both a wire staple and a zip tie. Nail the staple into the wood and then use the zip tie to attach the wire to the staple. That way the sharp staple can't damage the wire.
Engineered JoistEngineered I JoistSometimes these engineered joists are used instead of 2x10's or 2x12's. These joists are stiffer and quieter than conventional lumber. Engineered joists CANNOT be notched. Instead you must drill holes through the middle of the joist. Some have pre-made punch outs so that you don't have to drill. if you do drill your own hole, make sure it is at least 6" away from the end of the joist.
Engineered HeaderLaminated Veneer Lumber - Engineered Beam or HeaderOversized engineered beams are rarely used in homes except when special conditions require it. Some types of these beams can be drilled through and some cannot. The safest bet is to never notch or drill through a LVL Engineered Beam.
Aluminum FramingAluminum FramingAluminum studs should not be notched or drilled through. Instead use the pre cut holes in the studs to run your wires. The permade holes shouldn't have any sharp edges. If the edges are sharp and there is no grommet covering the opening, then you will have to get your own or run your wire inside metal conduit.
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