Small-scale In-wall wiring guide for home A/V

4-conductor speaker wire

This guide will help you save money by doing your own small-scale in-wall wiring projects in both finished and unfinished rooms. If you decide to hire a professional, the knowledge you gain will help you work through the process with your contractor.

Can you do the in-wall wiring yourself?

Is it legal?

In most locales, a homeowner is allowed to install low-voltage wiring. However, each state has its own code, as do some cities and counties, so check with your local authorities to be sure.

Are you capable?

The easiest scenarios for a do-it-yourself installer are those in which you can run wires in the attic, unfinished basement, or crawlspace. Use these spaces as much as possible, even if it means longer runs of wire.

If you’re new to this sort of work, look to tackle a relatively small project, like hiding the wires going to the rear speakers in your home theater.

Consider wireless options first?

There are a variety of wireless speakers, as well as some receiver/transmitter combos that work with regular amps and speakers.Before you start drilling holes in studs or cutting holes in your walls, consider today’s wireless music solutions. A lot of people ask us about wireless surround sound systems. For years there was no good answer. Now there are several.

Receive a free system design

Before you begin, you’ll need a plan. Do yourself a favor and submit a system design request to Crutchfield’s A/V Design team. You can upload a floor plan and pictures of your room and then chat with a designer about your goals. You’ll receive a free system plan and a link to a shopping cart filled with all the items you need to complete your project.

Things you’ll need

Always use wire that’s rated for in-wall installation. Look for speaker wire with a CL2 or CL3 rating (CL2P or CL3P if you’re placing it in heating ducts). You’ll want cable rated for direct burial if you’re running it through the ground to outdoor speakers.

Speaker wire gauge and conductors

In-wall speaker wire is identified in shorthand that indicates its gauge (thickness) and its number of strands (or conductors, as they’re known in the trade):

  • 16/2 is 16-gauge wire with 2 conductors
  • 14/4 is 14-gauge wire with 4 conductors

The lower the gauge number, the thicker the wire. For runs of less than 80 feet, 16-gauge wire will suffice. For longer runs, use thicker 14 gauge wire.

4-conductor speaker wireWhy pull two wires when you can pull one instead? Four-conductor wire has positive and negative wires for both left and right speakers inside a single jacket. It’s often used between an amplifier and an in-wall volume control or a stereo-input speaker.

How much wire should you buy?

After planning where you’re going to route your wire, you’ll need to figure out how much you’ll need. Ask your system designer for help with this. He or she can provide you with a wiring “map” — a plot that shows what you’re installing in each room, including all of the speakers, cables, brackets, and other items you’ll be installing.

Your designer can look at your floor plan and give you a solid recommendation of how much wire to buy. If you’re mapping out your own plan, think through where each wire will have to go. Pace off or measure each pathway. Tips:

  1. Allow extra wire for the connections. For example, if you intend to install ceiling speakers by yourself, allow 2-3 feet of extra wire so you can set the speakers on your ladder while you hook them up.
  2. Allow 10 to 15 percent extra: Your planned wire route might be thrown off by an unexpected obstacle. To be safe, buy at least 10 percent more wire than you think you need.

Audio/video cables

Most audio and video patch cables are not suitable for in-wall installation. Some

HDMI cables that are rated for in-wall use don’t support 4K or HDR video.

Fortunately there are some clever solutions, such as baluns, that use in-wall-rated network cable, coax cable

(RG-6), or even fiber optic cable to pass audio and video signals over long distances.

Celerity fiber-optic HDMI cableCelerity fiber optic HDMI cables keep the signal strong over long runs, and they’re immune to interference.

Wall plates and brackets

Your system designer can also help you determine how many and what kind of wall-mounted receptacles and in-wall volume controls you’ll need. You’ll also need mounting brackets to support the receptacles and volume controls. Your designer can add all of these parts to your system plan and a pre-filled shopping cart.

Wall plate for home theater connectionsThis receptacle accommodates the speaker and subwoofer connections for a surround sound system.

Universal wall plateThis universal wall plate gives you an entry or exit point for any kind of in-wall wire.

TV wall plateThese plates are part of a kit that hides both signal and power connections for a wall-mounted TV.

“Rough-in” or “hole-saving” brackets

These brackets for in-wall and in-ceiling speakers save a lot of time. The drywall installer will cut holes for the brackets before hanging the drywall (as they do for light switches and electrical sockets). You may have to order these separately — they may not be included with your speakers.

Hole-saving rough-in brackets for in-wall or ceiling speakers“Hole-saving” or “rough-in” brackets make it easy to install ceiling and in-wall speakers after the drywall is installed.

Outlet boxes

The hardware used to mount volume controls, wire outlets, and other in-wall devices are called junction boxes or “J-boxes.” Look for a J-box that’s deep enough to fit your in-wall devices (usually 2-3/4″).

Backless bracketsBackless brackets provide the minimum support you’ll need to attach a wall plate. The one at left is for a finished wall. It clamps itself to the hole you cut for it. The one at right gets nailed to a stud before your drywall goes up.

For a wall-mounted volume control, you need the structural strength and protection afforded by a standard junction box (available at home improvement stores). When you’re simply terminating wires at a wall plate, backless brackets will do.

Standard junction boxA standard junction box protects your in-wall volume controls.

Mount your outlets at the same height as AC outlets for a clean, uniform look. In-wall controls look best if you match the height of your light switches (usually located 44-48″ off the floor). Don’t attach low-voltage boxes to light switch boxes.

Nail plates

Whenever you drill a hole 1-1/4″ or less from the surface of any wooden part of your house (a stud, joist, plate, block, or brace), or notch any wooden part, you must protect the cable with a nail plate. The nail plate prevents a nail from ever piercing the cable.

Nail plateNail plates protect your wires from nails, screws, and drill bits.

Wire labels

Label both ends of the wire before you start pulling, or before cutting another wire. You can use Crutchfield CableLabels™, or simply use masking tape and a marker.

Crutchfield Cable LabelsCrutchfield’s self-adhesive, color-coded labels keep your audio, video, and speaker cables clearly marked.

Wire ties and attachments

Wire must be supported every 4-1/2 feet and within 1 foot of a junction box. Use wire ties and wire-tie clamps. The staples electricians use for regular AC wiring may damage low-voltage cables if they’re nailed down too tightly.

Wire wrapFor bundling cables at the back of a component, a reusable wire wrap comes in handy.