TUV Rheinland Tightens Annex H for Potting Compounds

On July 11, 2026, TUV Rheinland issued a technical supplement to EN 62368-1:2026 Annex H that changes the compliance baseline for potting compounds used in power modules for EU audio-video and IT equipment. For new certification applications, the material can no longer rely on a UL94 V-0 flammability rating alone; it must also meet CTI (Comparative Tracking Index) >=600V and be supported by a dual-parameter report from a TUV-recognized laboratory. This is worth close attention because the change directly affects certification preparation, material selection, purchasing documentation, and delivery planning across the relevant supply chain.

What the Annex H update now requires

According to the information provided, TUV Rheinland released the technical supplement on July 11, 2026. The update applies to all potting compounds used in power modules for EU audio-video and IT equipment under new certification applications.

The stated change is that, in addition to the existing UL94 V-0 flammability requirement, the material must also pass a CTI test at >=600V. The required evidence is a report covering both parameters, and that report must be issued by a laboratory recognized by TUV.

The rule took effect immediately on the date of release and is applicable to all new certification submissions.

Where the compliance pressure is likely to appear first

Material sourcing moves from single-parameter to dual-proof review

From an industry perspective, companies purchasing potting compounds may be affected first because the acceptance basis for materials has become narrower in practice. The immediate point of attention is whether existing supplier files include not only UL94 V-0 evidence but also CTI >=600V results, and whether the test report comes from a TUV-recognized laboratory. In procurement and incoming qualification, document completeness may become as important as the material specification itself.

Power module manufacturers face a certification handoff issue

Manufacturers of power modules for EU audio-video and IT equipment may feel the impact in certification preparation and project scheduling. Analysis shows that when a material used in the module no longer satisfies the updated documentation and test threshold, the issue is not limited to the material file; it can affect the timing of new certification applications and the readiness of technical dossiers submitted for review.

Certification and testing work gains an added verification step

Certification-related service providers and testing organizations may need to pay closer attention to how material evidence is screened before a new application is filed. What deserves closer attention is the new requirement for a dual-parameter report issued by a TUV-recognized laboratory. That changes the practical review focus from checking one familiar flame-retardant grade to confirming both performance parameters and report acceptability.

Export delivery planning may need tighter coordination

For exporters and supply-chain teams serving the EU market, the main exposure is in the handover between purchasing, compliance, and shipment planning for products entering new certification. Observably, the rule change matters less as a general market headline and more as a filing-condition change that can affect whether a project is ready to move through the approval process on schedule.

What companies should review now

Check whether current material files satisfy the new submission condition

Analysis shows that companies preparing new certification applications should review whether the potting compounds used in relevant power modules are backed by both UL94 V-0 and CTI >=600V evidence. If the available documents cover only one parameter, the compliance gap may appear before formal submission rather than after product launch.

Confirm the source and acceptability of the test report

The notification specifically refers to reports issued by a TUV-recognized laboratory. That makes report origin a practical compliance point, not only the test result itself. Companies should therefore pay attention to whether supplier-provided documents match this recognition condition before they are placed into certification files or customer-facing technical packages.

Review procurement specifications and supplier qualification language

What deserves closer attention is whether existing procurement specifications, approved vendor documents, and technical appendices still reflect the old single-parameter understanding. Where internal templates mention only UL94 V-0, companies may need to update the wording used in sourcing, quality review, and supplier communication for relevant projects tied to new EU certification applications.

Watch for execution details beyond the headline requirement

The information provided confirms the new requirement and its immediate effect, but it does not provide further execution detail. For that reason, companies should continue monitoring how the requirement is referenced in certification communication, technical file expectations, bid documents, and customer compliance requests, rather than assuming a fully settled implementation practice from the initial notice alone.

Why this looks like an execution signal, not just a technical note

Analysis shows that this update is more appropriately understood as an immediate compliance threshold change for new applications, rather than a distant policy direction. The reason is explicit in the information provided: the rule is already in effect and tied to a concrete documentation condition for certification. At the same time, it is still too early to treat every downstream consequence as settled fact, because the input does not include wider market feedback, application handling examples, or further written clarification on implementation boundaries.

From an industry perspective, the most relevant takeaway is that Annex H is now signaling a higher evidentiary standard for the material used in the specified power-module context. That makes continued observation necessary in areas such as certification interpretation, procurement document updates, and how consistently the new requirement is reflected in project-level compliance workflows.

How this update is best understood at this stage

At this stage, the update is best read as a rule change that has already landed for new certification applications involving the specified use of potting compounds in EU audio-video and IT equipment power modules. The practical significance lies in the shift from a flammability-only material checkpoint to a dual requirement covering UL94 V-0 and CTI >=600V, with report source acceptability built into the condition.

A neutral reading is that the notice creates an immediate compliance adjustment point for certification, sourcing, and submission preparation. It does not by itself prove broader market outcomes, but it does provide a clear enough signal for affected companies to review materials, documents, and supplier evidence without delay.

Basis of this article and points that still need verification

This article is based on the user-provided news title, event date, and event summary. The information available for writing consists of the stated TUV Rheinland Annex H technical supplement, the July 11, 2026 release date, the added CTI >=600V requirement alongside UL94 V-0, the requirement for a dual-parameter report from a TUV-recognized laboratory, and the statement that the rule took effect immediately for new certification applications.

For events of this type, commonly relevant source categories may include official notices, regulator or certification body publications, standards documents, industry association updates, trade or customs-related releases, and reporting from established industry media. A specific official source link was not provided in the input, so continued verification remains necessary.

What still needs to be observed includes any further clarification on execution detail, certification interpretation, document acceptance practice, changes in tender or technical specification language, industry feedback, and how affected companies implement the requirement in actual certification and supply-chain workflows.