EU Machinery Regulation substantial modification

Apply Article 3(16) as a cumulative test. Record the physical or digital change made after market placement or putting into service, whether the manufacturer foresaw or planned it, and whether it creates a new hazard or increases an existing risk. Then determine whether it requires either adding guards or protective devices whose processing requires modification of the existing safety control system, or adopting additional protective measures to ensure stability or mechanical strength.

A repair, service action, retrofit, or software update is not substantial merely because it changes the product or affects safety. If any element of the cumulative test is absent, the change is not a substantial modification under Article 3(16), although other safety, workplace, contractual, or product-compliance duties may still apply.

Do not use Article 18 in isolation for an importer or distributor. Article 17 separately treats an importer or distributor as a manufacturer when it modifies a product already placed on the market in a way that might affect compliance with applicable requirements. That trigger is worded differently from the Article 3(16) substantial-modification definition and needs its own assessment.

Make the substantial-modification decision traceable to a risk assessment. Identify hazards introduced by the change, estimate and evaluate any increased risks, identify the protective response, and record whether that response falls within Article 3(16)(a) or (b). A need for warnings, training, or another measure outside those two branches does not by itself satisfy the definition.

For machinery that is part of an assembly, document the affected boundary. Article 18 limits the modifier's manufacturer obligations to the affected machinery or related product when the substantial modification affects the safety of only that part, as demonstrated by the risk assessment. Explain why the remaining machinery or related products are unaffected.

If the cumulative test is met, Article 18 treats the natural or legal person carrying out the substantial modification as the manufacturer for the affected machinery or related product. That person must apply the Article 10 manufacturer obligations and the relevant Article 25 conformity assessment procedure to the affected scope.

A non-professional user who substantially modifies machinery or a related product for that user's own use is expressly excluded from Article 18 manufacturer treatment. The exception is limited to that actor and use case; it does not rewrite the definition or remove other applicable safety duties.

For a person covered by Article 18, the affected machinery or related product needs an updated compliance file covering the applicable Annex III essential health and safety requirements (EHSRs), Annex IV Part A technical documentation, conformity assessment, EU declaration of conformity, CE marking, instructions, safety information, and the risk-assessment evidence defining the affected boundary.

The conformity assessment should be selected for the modified product, not copied from the original file without review. Article 25 distinguishes products outside Annex I, Annex I Part A products, and Annex I Part B products, with different routes depending on whether harmonised standards or common specifications cover all relevant EHSRs.

For Annex I Part A machinery or related products, plan for a conformity assessment route involving a notified body. For Annex I Part B, internal production control is available only where the modified product was designed and constructed according to harmonised standards or common specifications specific to the category that cover all relevant EHSRs; otherwise, use the notified-body routes identified in Article 25. Products not listed in Annex I use internal production control.

The record should let a reviewer reconstruct the decision without knowing the project history. Keep both the threshold analysis and the resulting conformity work, including any conclusion that the change was not substantial.

For a substantial modification, retain the updated technical documentation and EU declaration of conformity for at least 10 years after the affected machinery or related product is placed on the market or put into service, and align the release evidence with its modified identity. Where only part of an assembly is affected, keep the risk-assessment rationale for limiting repeated tests or new documentation to that part.