The final instalment in our four part series where we offer guidelines on how to produce a specification for an IT cabling system. In Part 4 we review the different methods of testing data cabling (Certification, Qualification and Verification), and evaluate the importance of a warranty.
TESTING OF BALANCED COPPER LINKS
A structured cabling specification should state how the cabling system is to be tested and to what standard. There are three forms of testing:
- Certification – Tests all parameters required by ratified standards and provides a certificate for each channel or permanent link
- Qualification – Only tests the cabling to work for particular applications or network standards
- Verification – Tests only the most essential parameters.
Black Box Network Services recommends certification testing for every channel or permanent link. This should prove cost effective in the long term. It is a condition of most manufacturers’ warranties that the cabling system is 100% certified. The permanent link is the link from the distribution panels and the outlets whilst the channel also includes the patch core and equipment cables.
For every installation, where either certification or qualification testing is undertaken, complete individual test reports (or certificates where appropriate) configured in accordance with the agreed standard, should be included with the installation documentation. The format and material on which these reports are to be presented should form part of the contract.
CERTIFICATION TESTING OF BALANCED CABLING
Certification is carried out with a standards-compliant tester with the required accuracy for the Class or Category of cabling installed. You should state that the cabling system be certified to the BS EN 50173 series of standards, or your own country’s standards. By definition, certification testing includes qualification testing.
QUALIFICATION TESTING OF BALANCED CABLING
Where a manufacturer warranty is not offered, qualification is a less stringent alternative to certification.
- Uses less accurate test equipment to compare installed cabling performance with the requirements of specific applications
- Can only provide results for existing application standards
- Cannot provide any form of ‘future proofing’ as it deals only with existing applications
- Is limited to the ‘Channel’ test model, i.e. includes the equipment, patch and work area type cords.
VERIFICATION TESTING OF BALANCED CABLING
This will eliminate common installation errors but will not guarantee that the cabling system will support the network or bandwidth requirements. It provides:
- Minimum test and inspection for copper cabling
- A visual inspection of the terminations
- Wire-mapping test to confirm there are no open circuits, short circuits or crossed wires, including the cable screen if present. It will also confirm that telecommunication outlets and patch panels are identified and labelled correctly.
Plus, as an optional requirement, it can provide:
- Cable length
- Test to ensure there are no split pairs.
TESTING OF OPTICAL FIBRE CABLING
For optical fibre cabling, certification and qualification are essentially the same thing. There is not an acceptable less accurate alternative to the Loss/Length test set.
Certification / Qualification of Optical Fibre Cabling
- Polarity proofing by use of a visible light source
- Link length
- End-to-end power loss at the transmission wavelengths identified in the selected standard
- Calculation of power loss budget in accordance with the selected standard, allowing for the total number of connections and splices within the link
- Stringent adherence to the test method defined in the selected standard
- A final check for end-face cleanliness after certification, and cleaned as required with the correct materials.
Verification of Optical Fibre Cabling
- A visual inspection of terminations and splices
- Inspection for dirt and scratches using appropriate inspection microscopes, and where necessary cleaned with correct materials
- Optical fibre loss measurements using a light source and power meter to calculate loss budgets.
Plus, as an optional requirement, it can provide:
- OTDR measurements to determine length, and locate damage and poor connections.
MAINTENANCE AND SERVICES
BS EN 50174-1 states that “Repair and maintenance are generally captured by the contract between the cabling owner and the cabling maintainer”. Additional consideration should be made to ensure:
- A suitable maintainer (i.e. installations company/service provider) is identified where desired
- Records are updated to reflect moves and changes
- Alterations upgrades and enhancements are carried out in accordance with existing warranties, topology and standards
- Emergency support is considered.
Most cabling systems come with a warranty that covers the materials and installation for fifteen years or more (Black Box Network Services can offer a lifetime warranty). Some warrant that the cabling system will support specific applications whilst others guarantee to conform to a particular standard. These warranties are valuable and reassure you that the manufacturer has confidence in the cabling system. However, the warranties do not usually specify a response time or a fix time.
A few installers offer an enhanced warranty providing, for example, a timed response to a fault call. Cabling is often a critical part of your network so this type of warranty is beneficial for business continuity. There may be an extra charge and conditions attached to these enhanced warranties, which would be fully covered with a Service Level Agreement (SLA) for a cabling infrastructure. At Black Box we have a dedicated help desk facility, enabling us to provide tailored support contracts to suit customer requirements. We work to defined SLAs, covering response times, performance and fault resolution.
Depending on your experience and the complexity of the installation, expert assistance may be needed to complete the specification.