Last month, I covered some of the goings-on within the United States Congress concerning the deployment of fiber-to-the-home, fiber-to-the-curb, and similar initiatives that are aimed at providing broadband connections to residences. This month, I offer a collection of comments from earlier columns intended to help ensure if and when fiber does reach your home, you can take full advantage of it.
If you are in a position to build a new home, you are “sitting pretty” in terms of preparing your residence with work and entertainment infrastructure. But if you have learned anything from your time in the cabling industry, it should be that the future is difficult to predict. So, rather than guessing today which cable will best serve your home for its lifetime, the smart choice is to build the pathways into the home to allow for future upgrade.
For many years, wiring homes changed very little. The typical setup included wiring for 120-volt convenience outlets with a telephone jack or two and a twin-lead from the rooftop antenna or a coaxial cable from the cable-company box outside to the television.
How times have changed. Today we are seeing homes that tend to have all the same systems as commercial buildings but without the usual wireways, cable trays, and suspended ceilings used to support the cabling in a commercial environment. This is why it is very important to prewire new homes to not only meet current needs but also provide future flexibility and expandability.
I strongly believe that houses should be constructed with pathways within the walls to allow for upgrading the low-voltage cabling. The cabling will have to be changed to accommodate new technologies, but the pathway will last for the life of the structure.
The tricky part will be making certain that you place outlets where you will need them in the future. Most home-appliance manufacturers are touting Internet-capable kitchen appliances. I have seen, and played with, several prototypes at trade shows. An outlet box with a flexible conduit back to your “network operations center” may some day in the future contain the cabling connecting your refrigerator to “recipe central” for a report of what you can make for dinner using the items currently in the freezer. But you would not have to gamble today on which cable to install today. You could even wait until after you purchase the “smart fridge” and install the cable recommended by the manufacturer.
Don’t want to see a bunch of blank outlet covers? I suggest you take pictures after the pathway is placed and before the gypsum board is hung. It is a good idea to show a measuring tape in the picture extending from either a corner or door opening. The gypsum board is hung over the box. When needed, measure over and up to locate and cut-in the outlet. This is similar to an after-set floor monument in a commercial floor distribution system.
The ANSI/TIA/EIA-570B Residential Telecommunications Infrastructure Standard addresses two grades of residential cabling, but zero grades of residential pathways. But Carlon (www.carlon.com), a manufacturer of thermoplastic enclosures, fittings, and wire- and cable-management products has done an excellent job in a publication entitled Carlon Structured Cable Management Systems.
Remember, there is little worse than having to pothole through fresh paint, expensive wallpaper, and gypsum board to run just one more cable. So, why not lighten up on the contents (cables) and concentrate on the container?
While not everyone is looking for a $100,000 home-theater or motorized drapes in every room, you should at least consider the following:
• Hinge-switches on pantry and closet doors. Open the door and the light comes on.
• A distributed audio system with cabling for speakers, here, there, and everywhere.
• A control system that integrates HVAC, security, and lighting controls in one system. This allows “scenes” to be programmed. Imagine one touch of the “goodnight” button arms the alarm system, turns off the lights in the house, and sets the bathroom light at 7% as a night light.
• Add telephone and/or Web access to the control system and there is no need to wonder if you armed the security system or closed the garage door.
And for additional thought-provoking ideas, I suggest you read Residential Network Cabling-2002, written by BICSI and published by McGraw-Hill, ANSI/TIA/EIA-570-B-2003 Residential Telecommunications Infrastructure Standard, and visit Custom Electronic Design & Installation Association (CEDIA) at www.cedia.net and click on “homeowner.”
Cabling for broadband
75-Ω coaxial cabling is used for satellite, community antenna television (CATV), and closed-circuit television (CCTV) systems, but not all 75-Ω coaxial cabling is the same. As with most things, better quality will cost more, but not significantly more.
For broadband video systems (satellite and CATV), use Series 6 with aluminum foil and aluminum braid shields to properly shield the broadband signals and a copper-clad steel center conductor or bare copper center conductor surrounded by expanded foam for outlet cables and Series 6, 11, or hard-line trunk for backbone cable depending on the length of the run. You should require that the CATV system outlet cables meet SCTE IPS-SP-001 June 13, 1996, Flexible RF Coaxial Drop Cable specified up to 1,000 MHz and that the satellite system outlet cables meet SCTE IPS-SP-001 specified up to 2,200 MHz.
Baseband video systems (CCTV) commonly use coaxial cables with a 95% copper braid to properly shield the baseband signal and a bare copper center conductor typically surrounded by an expanded foam dielectric. Series 59 cable should only be used for baseband CCTV systems or for patch and equipment cords.
But requiring excellent cable is useless if the installer overbends, overpulls, and stretches or deforms the cable when installing it. So how much is too much?
The minimum bend radius should not exceed 20 times the cable diameter during the pulling, and 10 times the cable diameter once the cable is placed and terminated. The maximum pulling tension of coaxial is dependent on the size and material of the center conductor. For Series 6, the pulling tension should not exceed 40 lbf (178 N). While perfectly spaced cable clips look “neat and tidy,” we are not looking for tidy inside the wall studs. Have the installer vary the distance between the cable clips, to avoid degrading structural return loss (SRL) performance of the cable. Also have the installer leave at least 8 inches of slack at the outlet for future testing and retermination.
DONNA BALLAST is BICSI’s standards representative, and a BICSI registeredcommunications distribution designer (RCDD). Send your questions to Donna via e-mail: email@example.com