Projects · re-test
Cabling test results rejected? The usual causes, and how the package gets closed out
When the consultant sends the test pack back, the handover date moves. Usually the links are fine and the test setup was wrong.
Most rejected packs go wrong before the tester is switched on: the wrong limit, the wrong tier, or labels that do not match the as-built. By the time the consultant sends the pack back, the installer has often demobilised.
The most expensive cause is a tier mismatch, because it invalidates the whole submission rather than a few links. Under TIA-568.3-D, Tier 1 testing (link attenuation, length and polarity), measured with an optical loss test set or a light source and power meter, is the required test.
Tier 2, using an OTDR, is optional and supplemental. An OTDR can report total link loss, but TIA does not recognise it as a means of certifying fibre performance.
So a pack of OTDR traces submitted as certification is diagnostic data. A contractor who submits it in good faith can find the warranty promised to the client cannot be issued.
The other causes are smaller and more common, and each one can still cost the handover date.
- 01
The wrong test limit selected
Permanent link tested against channel, or the wrong category chosen on the tester. Every number looks healthy, and the pack is rejected against the specification it was meant to prove.
- 02
OTDR submitted as certification
Tier 2 data offered where Tier 1 is required. TIA-568.3-D asks for OLTS or LSPM for certification; the OTDR locates events along the link.
- 03
Reference not set, or set once for the week
The reference method and the day it was taken govern the loss budget. Set on Monday for a fortnight of testing, the results drift, and a reviewer can see it.
- 04
Labelling that does not match the as-built
The results are correct, but nobody can prove which link each one belongs to. Fixing it means a full re-walk of the hall.
- 05
Adapters out of calibration or wrong for the link
The adapter is part of the measurement. An out-of-date calibration certificate invalidates the set even when the readings look clean.
- 06
Exported as a PDF of a summary screen
Consultants check the native test file. A PDF of a summary screen does not let them, and the pack comes back.
Questions we get asked.
Is an OTDR enough to certify a fibre installation?
No. Under TIA-568.3-D, Tier 1 testing with an optical loss test set or a light source and power meter is the required certification test; Tier 2 OTDR testing is optional and supplemental. An OTDR reports total link loss and locates events along the link, but TIA does not recognise it as a means of certifying fibre performance. If a pack was submitted as OTDR traces alone, that is very likely the reason it came back.
The installer has demobilised. Can you re-test without them?
Yes. We test, certify and produce the results pack against your specification and your labelling schedule. Send the specification, the as-built and the reason the pack was rejected. The reason tells us how much of the hall needs re-walking.
How quickly can you start the re-test?
The start date goes in writing with the quote. Send the site region, the number of links and the deadline. If the date cannot be met, the first reply says so.
Can you take over testing before the pack is rejected?
Yes. We take the testing as its own package, or the whole cabling package, and test from the first panel onwards.
Who owns the results pack?
You do. It is produced in your format, under your labelling schedule, ready to submit under your name.
Can we hire a tester to work under our own site manager?
Yes. That is our Engineers service: testers on a day rate, on separate terms.
Send the scope, the specification and the programme.
We come back with our questions and a priced scope. No site name needed at this stage.