Moving toward standardization
Certain elements of the installation of wiring/cabling for residential low-voltage systems are on their way to becoming “standardized,” or at least looked at as benchmarks. Here is a closer look at some guidance for a “standards compliant” installation.
Remember there are “Grade 1” and “Grade 2” installations. They are:
Grade 1: Twisted pair and coaxial cable in a star topology to handle minimum requirements for telecom services (i.e., telephone, satellite, CATV and data services). Each outlet has one 4-pair UTP Category 3 cable and one 75-Ohm coaxial cable that meet or exceed requirements. Category 5 cabling is recommended to prepare a future upgrade to Grade 2.
Grade 2: Twisted pair cable, coaxial cable and optional optical fiber cable all in a star topology to handle requirements for basic, advanced and multimedia telecom services. Each outlet has two four-pair UTP Category 5 cables and two 75-Ohm coaxial cables that meet or exceed requirements, and optionally, two optical fiber cables that meet or exceed requirements. Category 5e cabling is recommended in place of Category 5.
Note that “cabling” refers to the cable plus the connectors.
First, meet with the developer and/or owner to lay out the location of the outlets, and then mark up the building plans to show the Grade 1 and Grade 2 locations.
Some additional guidance:
1. Include a minimum of one outlet for the kitchen, each bedroom and any reasonable unbroken wall space. Two outlets (now called “information outlets”) are recommended for the master bedroom, den or study and family room.
2. Position the distribution device (main cross connect) centrally (within the livable space) to minimize cable runs.
3. Design cabling home runs between the distribution device and the outlets. Remember: The maximum allowable distance between the distribution device and an outlet is 295 feet (90 m).
Before you begin:
- Put together a bill of materials for all hardware involved and use an average length for each cable type to arrive at a cost.
- Determine the cable types (individual, Siamese, multimedia or cables required for whole house audio, home automation, security, etc.).
- Inventory tools and test equipment.
- When you start wiring, note that no splices are allowed.
- Telecom wires should be separated from speaker wires, and if crossed, done at right angles.
- There are different pull forces and bend radii recommended for twisted pair cabling, coax and fiber.
- Cable ends should be labeled. (This helps when making connections in the distribution device.)
The actual wiring work involves:
- Connectors for the twisted pair cables (8-position modular plugs or jacks).
- F-Type connectors for the end of each coaxial cable.
- Optical fiber cables terminated per manufacturer recommendations.
- Modules within the distribution device (installed to meet the manufacturer’s instructions) with the cable ends marked for future testing, trouble-shooting and moves/adds/changes.
- The distribution device (or your cross connect) that is connected to the services coming in to the residence. These services could include telephone lines, CATV service, DSL lines, cable modems, satellite dishes, digital radio receivers, rooftop antennae and any energy or security monitoring.
Testing your installation
This is where you can provide the customer with proof that your part of the installation has been thoroughly tested as recommended. The following can be done:
- Test the entire grounded system. Here is where you can also recommend methods to provide circuit protection.
- Test the twisted-pair cable runs for continuity and wire map. See the tests outlined in the TIA 570-B standard.
- Test the coax cable minimally for continuity of inner and outer connectors.
- Test the fiber cable for optical continuity with a light source.
The TIA TSB being developed now for guidelines on using the Fiber Optic Loss Test Set may come in handy here.
Finishing your installation
Document, document, document! It’s easy to do if the job was done right, and the customer will appreciate your help. This involves listing cables and outlets out, providing test results, warranty information, instructions from manufacturers, and also leaving your contact information.
Following these guidelines can save you time, make the job more cost-effective and establish your professionalism. EC
MICHELSON, president of Jackson, Calif.-based Business Communication Services and publisher of the BCS Reports, is an expert in TIA/EIA performance standards. Contact her at www.bcsreports.com or firstname.lastname@example.org.