# Inspect, clean and reinspect every fiber end face under IEC 61300-3-35:2022 before mating

> Contaminated fiber end faces cause loss and reflections and can dirty equipment ports. The 2022 edition of IEC 61300-3-35 simplifies the workflow: clear the contact area, grade only the core and cladding, and let passing loss tests decide.

- Canonical URL: https://update.dsesecurity.com/updates/fiber-end-face-inspection-iec-61300-3-35-2022-workflow/
- Publisher: Detection Systems & Engineering (DSE Security)
- Author: DSE Security Editorial Team
- Published: 2026-10-18T21:00:17+00:00
- Modified: 2026-10-18T22:22:06+00:00
- Last reviewed by DSE: 2026-10-18
- Resource type: Checklist
- DSE priority: Information
- Topics: Networks & Infrastructure
- Reading time: 2 minutes

## What you need to know

Contaminated fiber end faces cause loss and reflections and can dirty equipment ports. The 2022 edition of IEC 61300-3-35 simplifies the workflow: clear the contact area, grade only the core and cladding, and let passing loss tests decide.

## Potentially affected

New fiber installations, moves, adds and changes, patch-cord replacement, test reference cords and troubleshooting on single-fiber and MPO links.

## DSE recommendation

DSE recommends making inspect-clean-reinspect a required step, with saved images or tester results, every time a fiber connector is mated.

## Article

Contaminated fiber end faces cause loss and reflections and can dirty equipment ports. The 2022 edition of IEC 61300-3-35 simplifies the workflow: clear the contact area, grade only the core and cladding, and let passing loss tests decide.

## Source facts

[Fluke Networks](https://www.flukenetworks.com/blog/cabling-chronicles/easier-fiber-end-face-inspection) advises inspecting, cleaning and reinspecting fiber end faces before mating connectors, including the test reference cord connected to a tester. Contaminated end faces can cause signal loss and reflections and can transfer dirt to clean ports on network equipment.

In the third edition, IEC 61300-3-35:2022, Zone C (adhesive) and Zone D (contact) are removed from the pass/fail criteria. The standard recommends inspecting the entire contact area first and removing loose particles that could migrate to the core and cladding; particles that survive several cleaning attempts are treated as embedded and acceptable, and inspection then proceeds to Zones A and B, which keep pass/fail limits. MPO connectors follow the same approach across the whole ferrule.

The most notable change is that a connector cleaned of loose debris but failing inspection may still be used if it passes optical performance tests for insertion loss and return loss.

## Applicability

Use this for single-fiber and multi-fiber MPO connectors on any fiber backbone, data center or camera network. Fluke notes that its inspection tools now grade against the 2022 edition, and that a failed inspection still appears on test results to aid later troubleshooting.

## DSE recommendation

DSE recommends making inspect-clean-reinspect a required step, with saved images or tester results, every time a fiber connector is mated. Specify IEC 61300-3-35:2022 grading in installation contracts, inspect and clean test reference cords before every test session, clean MPO ferrules as a whole before grading individual fibers, and treat a failed inspection with passing loss results as acceptable only when the insertion-loss and return-loss evidence is recorded.

## Verification

For a sample of new or changed links, check that the closeout package contains end-face results for both ends, the grading edition used, and Tier 1 loss results. Any connector accepted on optical performance after a failed inspection should show both records together.

## Official reference

[Fluke Networks — Easier Fiber End Face Inspections: Key Changes to IEC 61300-3-35](https://www.flukenetworks.com/blog/cabling-chronicles/easier-fiber-end-face-inspection). Reviewed October 18, 2026.

## Primary reference

- Name: Fluke Networks — Easier Fiber End Face Inspections: Key Changes to IEC 61300-3-35
- Authority: Fluke Networks
- URL: https://www.flukenetworks.com/blog/cabling-chronicles/easier-fiber-end-face-inspection
- Source publication date: Not stated by the source

## Citation and use

Preferred citation: “Inspect, clean and reinspect every fiber end face under IEC 61300-3-35:2022 before mating,” DSE Security, https://update.dsesecurity.com/updates/fiber-end-face-inspection-iec-61300-3-35-2022-workflow/
Publishing principles: https://update.dsesecurity.com/updates/dse-updates-editorial-methodology/
Usage and citation policy: https://update.dsesecurity.com/usage/
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