In this chapter we talk about some things to look into and perhaps install while you under construction --- just in case you need it in the future. It's easy to pull extra wire while you are at it.
Pre-Wire Your New Home - Chapter 4 - Future Proofing
David Feller | BOCS
Pre-Wire Your New Home: Plan For The Future
Chapter 4: Future Proofing
Author: David Feller,
This is the third installment of a multi-part series covering all aspects of low voltage wiring in the home: entertainment, security, automation, and future planning. A new section will be published every few weeks.
Table Of Contents:
- Chapter 1 - Seriously, Why bother?
- Chapter 2 - Can I actually get away with this?
- Chapter 3 - The Absolute Minimum – and Why…
- Chapter 4 - Future Proofing
- Chapter 5 - The Actual “Pull”
- Chapter 6 - Whole-Home Audio
- Chapter 7 - Proper Terminations
- Chapter 8 - Things to avoid
- Chapter 9 - Whole-Home Video
Chapter 4: Future Proofing
Aren’t we doing this already by installing wires in the walls before we even need them?
The hardest part of picking what to pre-wire is making the tradeoffs betwee n what you need the day you move in, what you likely will need over the first 5 or 10 years in the home (technology you are aware of but not installing yet due to budget, time restrictions, etc), and planning for long term upgrades with technology that might not even be invented yet.
What about wireless? The most common question – isn’t everything going to be wireless in the future? Anything can be done wirelessly, but with few exceptions, wired is always cheaper, more reliable, more efficient, and easier to get set up and running.
Key recommendations from experts:
- Start with the minimum that every home needs both to serve daily basic needs and stay competitive on the housing market (See Chapter 3, The absolute Minimum, and why). Get that all in the wall up front.
- Carefully think through every possible system that you may want to install or have installed in the next 5-10 years and go ahead and pull those wires in-wall prior to drywall (See Chapter 6 Home systems to consider). Pulling raw wire is easier and therefore less expensive and time consuming now.
- At a minimum, pre-place conduit to key entertainment areas and key home control locations for future expansion. If you use conduit, do not put any wires in it as part of your pre-wire. Why fill it up now, it is insurance for later.
Conduit, Tell me More:
Since we are talking low voltage cables, there are not the same requirements as for electrical regarding wire types, insulation, cooling factors etc. Basically we just want a simple way to get a wire from the wiring closet up to a location where a piece of equipment or entertainment control is located. Functional not fancy is the plan.
How Big, what kind?:
Within reason, size matters as you can get more wires, they are easier to pull, and you will spend much less time doing so with larger conduits. The key governors tend to be cost, ease of installation, and conformance to codes. Larger is more expensive, and the bigger it is the more awkward it is to get in the right place but the critical factor in most homes is conformance to code so we will focus there next, but at least 1.25” is advised. As for type, you are not looking for “protection” or shielding so something that is easy to pull wires through and is cheap is your goal. Most home improvement stores have a lot to choose from. It generally runs about $1 a foot and you need to purchase the right clamps with it as well.
Some examples include:
- Carlon Raceway - http://cableorganizer.com/carlon/carlon-flexible-raceway.html
- Smarthome selection – www.smarthome.com search on conduit
- Cinemabuilder - http://www.cinemabuilder.com/products/construction/wiring-conduit.asp
Be sure to get clamps and terminal adapters as well so you can connect to mud rings.
How much wood can I cut?
You should most definitely check local codes, verify with your local inspector, and specifically seek council and permission of your builder before cutting or modifying and wood members of your home. And most definitely read and obey the previous sentence! That said, common practice and most codes abide by the following ratios for holes and chunks that can be cut from studs, plates, and members in your home.
Load Bearing members (if the member carries the weight of the structure above it):
- A hole can be up to 40% of the width of the member if it is centered.
- A notch (a cut out from the side) can be up to 25% of the width of the member.
NON-load bearing members
- A hole can be up to 60% of the width of the member
- A notch can be up to 40% of the width of the member
Most of the time, what you are cutting through to install conduit is the top plate. If there is any confusion, ask the builder or inspector what is load bearing and what is not – many plates are not. A good rule of thumb is if the wall can be removed without effecting the rest of the structure then it is not load bearing. If your basement has concrete walls (on which the floor above sits) then the added interior walls are non load bearing. Even if ceiling joists or roof jacks pass over a wall it could still be non load bearing especially if the joists do not end on top of the wall in question.
If your walls are 2x4 walls (actually 3.5” wide):
- If it is load bearing your hole can be 40% diameter 3.5”X.4= 1.4” or a 1 3/8” hole through which 1 ¼” OD conduit will slide.
- If it is non-load bearing your hole can be 60% diameter 3.5”X.6=2.1” or a 2” hole
If your walls are 2X6 walls (5.5” wide) the same math applies
- Load bearing up to a 2.2” hole
- Non-Load bearing up to a 3.3” hole
DO NOT drill through structured wood joists (They look like pressed or laminated wood) without permission and an engineer’s signoff. These are specifically designed for load bearing and you could cause huge rework issues.
DO NOT drill new holes in T-lam or wood I beam/floor joists without permission and either and engineer’s signoff or strict compliance to the documentation that comes with these joists and approval of the builder. Note that most of these have pre-started holes that can simply be knocked out with a hammer saving all the extra math and nervousness. At a minimum keep holes, cut or hammered out, 12” from ends, load bearing points and beams.
Generally, you need to follow the same rules as when installing wires both for good common practice and to meet some local codes.
- Get an “Auger Bit” – Much easier than a hole saw and they pull themselves through the wood – multiple layers of it – easily.
- Attach ends securely to something – most mud rings have an attachment point
- Fasten to members within 12” of a box and every 4.5’ vertically, within 12” of where it passes through a member, and support horizontally every 4 to 6 feet.
- The pull string. A lot of conduit comes with a pull string already inside, if not you can insert one during installation or run one later. Masons twine works well and is incredibly strong. For running through an empty pipe, a cotton ball can usually be sucked through the pipe with a vacuum.
- Seal around the conduit where it passes through fire structures – expanding foam works well.
- If it comes within 1 ¼” of the surface, put on a plate to prevent nails/screws from penetrating it.
- Some conduit connectors are directional – you can usually pull wire either way but be consistent in installation so you know what is in your walls.
Where should I put it?
Depending on the home construction – if you have an accessible attic, unfinished basement, or crawl spaces and your budget, you can forego it altogether or do full runs back to the media cabinet.
As a minimum, 8 to 10 foot runs from each TV/media/entertainment location up into the attic is a good start. Consider also putting mud rings with blank plates and conduit up to the attic near key switch/entry locations, to the kitchen, near the thermostat, to the front door/doorbell location, near the door in the master bedroom and each bedroom, and outside near the backdoor. These will allow later installation of new A/V cables (HDMI will have to be replaced eventually), home automation and control, and multi-room audio/video systems.
If you live in a multistory home, make sure you have a chase or a large conduit from the attic to the basement (where most media cabinets are located) at least 2” and preferably 3” in size and a conduit from where that comes down to the media cabinet itself.
For the Home Theater, a separate run to each speaker, TV, projector, control panel, and source location to the associated media cabinet is highly recommended. Standards change. Be sure to leave conduits empty for the future.
Appendix A: Links to sources, references, and products:
- http://www.crutchfield.com/learn/learningcenter/home/mrintro.html Crutchfield on multiroom systems
- http://www.smarthomeusa.com/info/prewire/#pre Prewiring basics from smarthome
- http://www.crutchfield.com/Learn/learningcenter/home/multiroom_remote.html remote control systems from crutchfield
- http://www.hometech.com/learn/audio1.htm home tech solutions whole home audio intro. There are some more detailed speaker placement guidelines and some good ideas for combining home theater and whole-home audio/video room/plans.
- http://www.xantech.com/Downloads/Training/ Xantech IR training powerpoints
Products referenced in this guide:
- http://www.audioauthority.com/product_details/scp-11 Baluns – single Cat5 for component plus digital audio
- http://www.cepro.com/article/review_russound_c_series_multiroom_audio_system A review of the Russound C5 by CEPro
- http://www.russound.com/cseries_system.htm The Russound C-series (Search on internet for good direct pricing)
- http://www.nilesaudio.com/products_niles.php Niles audio products - multizone systems, multizone amps, wall controls etc.
- http://www.nuvotechnologies.com/ The main nuvo website with a nice selection of systems
- http://www.provantage.com/tripp-lite-p568-050-ez~7TRPA1T6.htm HDMI cable specifically made for pulling through conduit – circular pull off ends.
- http://www.bocsco.com BOCS Whole-Home Audio/Video distribution over COAX
With 20 years in the Consumer Electronics space, David pioneered wireless LAN for home use in partnership with Linksys, rotating storage for portable electronics at Cornice, and is most recently a founder and chief marketing officer of BOCS Inc, the manufacturer of a new whole home A/V distribution system for retrofit applications
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