Wire Routing and Installation

In this section:

Wall Boxes
Routing Around Electrical
Drilling Holes
Planning Routes and Pulling Cable

Running three miles (15900') of cabling proved to be quite a challenge! The keyword here is "planning". Foresight and organization will make all the difference. Here are the tips we learned, some from others, some from our adventures.

Wall Boxes:

Plan out your wall box locations first. A good spot for volume controls, A/B switches, keypads or IR receivers is near a light switch to keep groups of switches together in a room. However, you may want to mount the volume control and A/B switch near the head of a bed in a bedroom. Keep the audio controls on studs across from the switches (one stud away) to avoid the AC interference. We put the double-gang box for the volume control & A/B switch at the same level as light switches (44" from floor to bottom of box) and put the keypad/IR box just above the volume and A/B box (closer to eye level), since you are more likely to need to see the keypad, either to read the keys on the pad or to read an LCD display. Keypad/IR boxes were put 52" above the floor (BTW, we put thermostats at this same height for consistency). Use a single-gang wall box for infrequently used keypad locations and double-gang boxes where you may want to install a larger keypad with more features. NOTE -- strange as it may seem, cut the backs off all boxes for which a volume control is destined! Some volume controls are very deep, and do not fit even the deep electrical wall boxes (I had 3" deep boxes). The volume controls that I looked at (Niles) had a circuit board that just did not fit. SoundTrack installers cut the backs off all their boxes with a band saw before going on site. We put TV and phone boxes at electrical outlet heights (13" from floor), again at least one stud bay away from AC outlets.

Routing Around Electrical:

The main thing to watch in routing low-voltage signal cable is avoiding high-voltage AC wiring. It is OK to cross low voltage signal and speaker wires at 90 degrees to electrical wiring (cross perpendicularly), but avoid running parallel and close to electrical wiring. This will cause noise in speakers (at low volumes) and could cause data errors in data lines. Everyone told us to do the low-voltage wiring after the electrician has finished his pre-wire! I heard several "horror stories" about running speaker wires then later finding the electrician liked the holes that had already been drilled, and used the speaker wire holes for his electrical wire. One installer even drilled holes through many joists to get a path, went back to where he started the holes, and found the electrician filling his new holes with electrical runs. If you do any wiring on outside walls, make sure you do it before insulation!

Unfortunately, there is often very little time between the completion of the electrical pre-wiring and the start of insulation and drywall. We were unable to start our wiring after the electrician due to scheduling; in fact, we started before the electricians. Fortunately, the electricians were very understanding about our wiring (a rare attitude, according to my contacts), and were very conscientious about crossing at right angles and not running parallel to our wires. Even so, we had to re-run some cable paths when the electricians ran too close, especially on long runs. The rule of thumb in this case is, if there is an easy path and a hard path, take the hard path because the electrician will take the easy path.

I have heard several differing views on the minimum separation between parallel runs of AC and low-voltage cabling -- anywhere between 6 inches and 4 feet, depending on who you talk to. In the CEBus Installer's Guide under twisted pair installation, they say keeping 6 inches between the TPBus and AC wiring is good. However, I've heard that AC wires produce a field 18" out from the wire. Others say to keep 3 to 4 feet away. Therefore, I tried to keep at least the 3-4 feet where I could, but dropped down to 16" for shorter runs. You will frequently want to run wires to a box near a switch or floor outlet, so running along the opposite stud (16" centers) in a bay to get to the outlet is common. And, the "no parallel runs" rule can be violated for short distance if absolutely necessary, such as to get over a door frame or tight locations that leave no alternatives. SoundTrack says that Monster audio cable can run up to 10 feet parallel to AC (1 foot from the coax), coax can run 25 feet (or much more for Monster coax), and other low voltage wire can run about 2 feet without much chance of problems. You should never run the cable in the same holes as AC for parallel runs -- keep at least some separation, and keep parallel runs very short. Low voltage wiring should also never go into the same wall box as AC.

Drilling Holes:

For drilling holes through wall studs, use auger bits, not spade bits. Augers have a screw-tip to pull the bit through, and they cut the hole cleanly while taking out large chunks for a quick hole. I purchase two bits -- a 5/8" bit, which allowed room for the two coax and phone/LAN cables for the typical TV outlet, and a 1" bit for all the wires in a room, leaving a little to spare. Don't use a bit larger than the 1", and center the hole in the stud. If the edge of the hole gets closer to the edge of the stud than about 1", you should apply a nail plate to protect the wires from drywall screws. A good 3/8" electric drill should drive the 5/8" auger bit through a single stud (good 12 volt battery operated drills worked for us for a few holes here and there, but you need a second battery to keep on the charger), but you will probably want to rent a heavy duty " right-angle drill for lots of stud holes, doubled-studs, and the 1" bit. However, plan out your routes before renting the drill and spend time up-front getting all the holes drilled first to avoid excessive time renting the drill. If you use a standard drill (instead of the right-angle drill), you will not be able to get straight holes through the walls (due to the length of the drill/bit combo), and pulling the wires will be more difficult and may increase the chance of damage to the wire due to the angled nature of the holes. I could not find anyone who could tell me how many holes can be drilled vertically in a wall stud, even for a load-bearing wall. Neither the electrician nor the contractor could tell me for sure, though they seemed to think that it was not critical -- they recommended keeping the holes at least a foot apart. For horizontally-running support studs, it seemed OK to even drill most of one out. However, check your local building code. I kept my number of holes to a minimum just to ensure wall integrity.

For major cross-house runs through joists, a 2" or 2 " hole saw is useful. A lot of wire will go through a 2 " hole -- we ran most all of our first-floor audio cables through a single run of 2 " holes in floor joists. When drilling through floor joists, keep your holes away from the supported ends of the joists since that is where the sheer force is located. I was told to keep holes away from the bearing point at least three times the height of the joist. Therefore, for an 8" joist, don't drill closer to the bearing point than 24". From there, for every foot from the bearing point, you can drill a cumulative 1" diameter hole. Thus, two feet from the bearing point you can drill a two inch hole. There must be some limit to this rule of thumb, since an 8" hole in an 8" joist 8 feet from the end doesn't work, but the basic idea seems logical. In our case, things were a little safer since we used TJI ("Silent Floor") joists. These are those "I" beam-like joists built of plywood 2x2s top and bottom with particle board "webbing" between. These tolerate more holes since the joist has compressive force on the top 2x2 and expansion force on the bottom, and the particle board webbing doesn't do much except hold the two together. Therefore, holes kept in the center of the webbing are not as critical. However, the sheer force is still on the ends of the joist and you should not drill close to the ends of joists. In spite of these guidelines, I found the electricians and plumbers did not always follow them. But, I kept to the guidelines so as not to compound any issues. Of course, local building codes prevail.

Several sources warned me not to touch laminated wood beams (lam beams). I was told that drilling a single hole in a lam beam could have the inspectors require tearing out the beam and replacing it! Lo and behold, one day I noticed two holes the electricians had bored through one of the lam beams! The contractor just said we would have to get a letter from the structural engineer accepting those holes, but he had the electrician stop drilling lam beams. The electrician said he did it all the time with no question, except in some towns (the horror story about tearing out the beam came from someone who built in one of these towns). So again, check not only local building codes but the attitude of local inspectors before drilling lam beams (or steel beams). I completely avoided putting my own holes in lam beams just in case.

Planning Routes and Pulling Cable:

We spent more time finding routes for runs and individual locations than we did actually drilling holes and pulling cable. Plan main cable runs along the full length of the house from which you can split out individual runs. Make sure these main runs are well away from AC runs (electricians will be putting in such main runs, too) due to the length and number of signals that would be affected by noise. Ensure that such main runs (or any smaller runs) do not get blocked by a lam beam or steel beam, and that they can hold all the wire. A good, easy location is across the lower member of roof trusses. You can tape together the ends of several wires going along the run, tie a string to the end, tie a weight to the other end of the string, and just toss the weight over a few truss members then pull the wire across. This saves the time of climbing a step ladder, feeding the wires, back down the ladder, drag it a few feet, back up, etc., etc., etc. When pulling through trusses, do not pull the cables through the center of a "V" section -- the wire will settle in the bottom of the "V", and settling of the house or expansion/contraction may pinch the cables, possibly causing shorts or cuts years down the road. When pulling the cable, either through holes in studs or across trusses, pull slowly. Pulling too fast will friction-heat the wood, and when you stop pulling the hot wood can melt or burn the PVC cable jacket. And, of course, don't yank or pull the cable too tight, especially around corners or areas that might get pinched or kinked -- it's not worth breaking a wire, which may not be found until it is way too late.

A numbering scheme for the cables is useful. SoundTrack recommended using three digits on each cable. The first digit for the floor, and the second two as sequential numbers for types of wires (00-20 for speakers, 21-30 for keypad, 31-50 for coax, etc.). However, I found it more useful and convenient to use the first digit for the node location (0 for basement, 1 for media room, 2 for security center, 3 for all other point-to-point wires) and the other two digits just sequential regardless of wire type. I kept a log of all wires run, and the sequential listing grouped the cables by room (110-116 all went to the same room, for example). We numbered both ends of the wire with a fine-point permanent marker, directly on the white jacket of larger cables and on white electrical tape for smaller wires or black cable. After I set up the centers and finalize the exact locations of the cut ends on the mounting boards there, I will re-number the cables neatly with pre-printed number tape or a label printer (I use a Casio; similar to the popular labelers by Brother). You can get the number tape from 3M in spools of individual numbers, or from other companies in booklets of number strips. Look in your local electrical supply stores for these numbering tapes. I will cover the taped numbers with clear heat-shrink tubing for permanence. After running all the cables, go back and check off each and every number in your log against both ends of the cables -- I found a couple marked with the wrong number on one end, and a couple not marked at all. If you don't find these until the drywall is up, it will be harder to trace the cables! Use a continuity checker if necessary to test those unknowns (strip two wires in a cable at one end, twist them together, then test for continuity between those wires at the other end). See the Wiring Ideas for how I used Sidekick for Windows to organize my wire charts containing the numbering records.

If you have several people helping you run cables, organization during the cable pulling is even more important. We often ended up with a couple of people scratching heads and planning a route around AC cables, lam beams, and congested locations, while everyone else sat around waiting to drill holes and run wire. Plan the main routes and many of the individual routes in advance; paint or mark the paths on the joists and ensure you don't get trapped by impassible lam beams 3/4 of the way to the destination. After planning and marking runs, then rent the right-angle drill and bring in the crews. One person is usually enough to run the drill -- start that person first. We found two people the ideal for each run of wire-pulling. There's a lot of back-and-forth running to get around corners with only one person, and three people are too many except for long runs. We borrowed a cable spooler rack to put several spools on and put it at the central node. You can also use the electrician's trick of nailing a piece of conduit between two wall studs and putting the spool on the conduit. Tape together as many cables as practical (for example, a full package of the two coax, phone, and LAN destined for one room's TV outlet, or several speaker cables with keypad/IR wires going to a group of bedrooms through the same chase). Use two step ladders when feeding through joists, and have one feed wire through to the other, leap-frog a step ladder, etc.

After running the wires, staple them to the studs to avoid getting a wire pinched between the drywall and the stud. For individual cables, I found the Arrow T-59 stapler invaluable. It uses a plastic-insulated staple that is curved on the inside to just exactly fit an RG-6 coax cable. It also works well for the speaker wires -- a little loose for the 16-2 and a little tight for the 14-4 and IL200, but works for these too if you are careful. For bundles of cables, use those plastic insulated staples (hammer needed) used for AC electrical wire. I also used the metal electrical wire staples, but didn't drive them deep enough to pinch the cable. Keep the cables in the middle of the stud to avoid an angled drywall screw or one that just misses the stud (believe me, they miss the stud frequently).

After you run the wires to an open-back wall box like for a volume control, tape all the wires together so they can't get lost below the box. Staple cables close to outlet boxes to also reduce the possibility of lost cables. Drywall installers will push the wires out the back of the box to get them out of their way. I also put little sandwich baggies over the cable ends in each box after wiring to prevent texturing and plaster from messing up the cables and labeling. Stuff all cable ends completely into the boxes to avoid damage during drywall.

If you use surface-mount speakers, drive a nail into a stud at the location you will terminate the wire and tape the wire to the nail so it sticks out into the room. Dry wall installers are notorious for hiding anything they can behind the dry wall. The nail with the wire is a more sure indication that the wire must be brought through the wall. Don't rely on a walk-through with the planner -- it's the guy driving the nails you must guide. If you use recessed wall speakers, locate the wire where you want it, coil it, and photograph and document its location. Putting speakers on outside walls may not be a good idea, but if you do it, make sure you pull the wire through the insulation after the insulators hide it from you. SoundTrack recommends getting the drywall up, or even finished, before cutting the hole for in-wall speakers so you can carefully fine-tune where you want the speaker on finished surfaces instead of a visually different set of studs. Other sources recommend installing a "hole guide" before the drywall goes up so that the drywall installers will cut and finish the hole for you. However, I've found that these hole guides cost anywhere from $10 each to $40 for a mounting bracket per speaker! I'm going to stick to the speakers that include the mounting bracket in the price of the speaker (Polk has some nice ones; we purchased their top-end in-wall model AB 805 speakers for about $390 per pair, and their mid-quality in-wall AB 705 speakers for about $290 per pair). See the section on finishing the installation for details on the mounting process. Surround-sound speakers should be mounted about seven feet from the floor (avoiding direct sound to the ear), and normal audio in-wall speakers should be installed about ear level (to ensure direct sound). These are ideals, and what you really do will probably depend on how it looks in that room, or other limitations of the room layout.

I estimate we spent about 42 people-days (8-hour days) on the whole pre-wire project, which was almost 16,000 feet. Of course, this included a lot of head-scratching while planning routes, some inefficient use of many people the first weekend while we got organized, and some post-installation time doing checking and verifications.