IT Infrastructure
Cabling test reports: what to check when accepting network cabling
Only a certification test shows whether every link meets the limits of its class. What gets measured, what a good test report contains and when you should ask questions.
Q-entra editorial teamPublished on 6 min read
Contents
Key takeaways
- Only certification testing proves that every link meets the limits of the planned class under EN 50173 or ISO/IEC 11801.
- Acceptance testing is usually done on the permanent link, the fixed installed cabling without patch cords.
- A good test report states the test limit, the tester, its calibration date and the margin to the limit for every single link.
- Complete test data is usually a precondition for a manufacturer warranty and saves time when faults occur later.
- Missing links, the wrong test limit or a bare list of passes without detailed values are red flags.
Why test reports are more than paperwork
When you accept new cabling, one thing matters most: every link must have been measured with a certification tester against the agreed test limit. The test report proves this for each link, with the limit, the tester, its calibration date and the margin to the limit. You cannot see from the outside whether cabling delivers the planned performance, and it usually outlasts the devices connected to it.
The test report is therefore proof of quality at acceptance, the basis for a manufacturer warranty and a valuable tool for later troubleshooting. If you decide what will be tested and how it will be documented when planning the structured cabling, you avoid arguments at the end of the project.
Permanent link or channel: what exactly is tested
The permanent link is the fixed installed section from the port on the patch panel to the outlet at the workstation, including the connectors at both ends. The standards limit it to 90 metres, and it stays unchanged for the life of the cabling.
The channel also includes the patch cords in the cabinet and the equipment cord to the end device, up to 100 metres in total. Because patch cords are often swapped, a channel result only applies to the cords used during the test, so new installations are normally accepted on the permanent link.
| Aspect | Permanent link | Channel |
|---|---|---|
| Scope | Patch panel to outlet | Including patch and equipment cords |
| Maximum length | 90 m | 100 m |
| Typical use | Acceptance of new installations | Troubleshooting, checking a specific connection |
| Validity | Valid as long as the link remains unchanged | Only valid with the cords that were tested |
What a certification tester measures
A certification tester measures every link across the full frequency range of its class and compares the results with the limits set in the standard. For copper cabling, these are the main parameters:
- Wire map: Are all eight conductors terminated correctly? The test detects opens, shorts, reversed pairs, crossed pairs and split pairs.
- Length and propagation delay: Length is calculated from the signal's travel time. The tester also checks the delay difference between pairs (delay skew).
- Insertion loss: How much is the signal weakened along the link? Loss increases with length and frequency.
- Near-end crosstalk (NEXT, PS NEXT): How much do neighbouring pairs interfere with each other? Pairs untwisted too far at the termination are a common cause.
- Return loss: How much of the signal is reflected by irregularities, such as kinked cables or poorly terminated conductors?
- Further values: far-end crosstalk (ACR-F), DC loop resistance and resistance unbalance, which matter for PoE among other things, and shield continuity on shielded systems.
For unshielded Cat 6A systems, alien crosstalk between neighbouring cables can also be measured on a sample basis. Fibre links are tested with a light source and power meter for loss, length and polarity. The loss limit is usually calculated from the link's length, connections and splices. An OTDR trace can be added to make individual splices and connectors visible. Our article on singlemode and multimode fibre explains the fibre types.
Standards and limits: class, not category
In Europe, cabling requirements are set out in EN 50173, and internationally in ISO/IEC 11801. Both distinguish between the category of individual components such as cables and jacks and the class of the installed link. A link built from Cat 6A components is tested against the Class EA limits, which are defined up to 500 MHz. The US TIA-568 series uses category for the link as well, so a report may show a TIA limit instead. That is not wrong, but it should match what was agreed.
A link is only as good as its weakest component. A Cat 7 installation cable terminated with Cat 6A jacks gives you a Class EA link, not Class F. Our article on choosing the right network cable explains which combination makes sense for you.
Requirements for field testers and their accuracy are defined in standards such as IEC 61935-1 and the US standard TIA-1152. The tester must suit the class being tested, have the right adapters and be calibrated regularly.
What a good test report contains
A test report should make every single link traceable, even for someone who was not there during testing. Look for these details:
- A unique link ID that matches the labels on the outlet and the patch panel
- The test limit used, for example Class EA permanent link to ISO/IEC 11801 or EN 50173
- The cable type and the nominal velocity of propagation (NVP) set on the tester, because the length reading depends on it
- The tester's model, serial number, calibration date and software version
- The date, time and name of the person who carried out the test
- The result for each link with the margin in dB for the main parameters, not just pass or fail
In addition to the PDF summary, ask for the test data in the native format of the tester software, so that the results can be reopened, analysed or sent to a manufacturer later.
Acceptance, manufacturer warranties and documentation
Acceptance
State in the tender specification that every link will be tested, which class and test limit apply and in which format the reports will be handed over. Testing takes place once installation is complete and no further work by other trades could damage the cables. On larger projects, a few links are often retested in the presence of the client.
Manufacturer warranties
Many manufacturers of cabling systems offer long-term system warranties. The usual conditions are components from that system only, installation by a qualified partner company and complete test data submitted on time. Clarify these conditions before the project starts, not at handover.
Labelling and documentation
Test reports only help if every link can be found on site. Outlets, patch panel ports and both ends of each cable should be labelled consistently, and the IDs must match the report and the as-built drawings. Keep the documents for as long as the cabling is in use. Sound planning and project engineering defines this scheme before the first cable is pulled.
Red flags in a test report
- Links are missing, or the number of reports does not match the number of outlets
- The test limit does not match the planned class, for example Class E for a Cat 6A installation
- There is only a list of passes, with no detailed values and no native data
- The calibration date is missing or older than the tester manufacturer recommends
- Many results sit close to the limit or are flagged as marginal
- Suspiciously identical values, lengths or timestamps across many links
- Permanent links longer than 90 metres without a plausible explanation
None of these points automatically means poor workmanship, but each one should be clarified before acceptance. Q-entra can help if you would like an existing report assessed or are planning new cabling with complete testing and documentation.
