Glossary · Machinery law and conformity

Substantial modification

German: Wesentliche Veränderung

Under the EU Machinery Regulation, a substantial modification is a change to machinery after it has been placed on the market or put into service, not foreseen by the manufacturer, that may create new hazards or increase existing risks sufficiently to require new protective measures. The person making it takes on the manufacturer’s obligations for the modified machinery.

Compliance
EU

In one sentence

A substantial modification changes machinery in ways that create new hazards or raise risk enough to trigger manufacturer obligations for whoever makes it.

Example

A plant operator adds a robot to an existing press line and changes its control system so that new hazards arise at the transfer point; the operator must perform a conformity assessment for the modified line as its manufacturer.

Explained in context

Context cards connect this term with others to answer one question. Also in British English and German.

Retrofit and substantial modification under the Machinery RegulationWhen does a retrofit make the operator the manufacturer of a machine?UK Deutsch

How it applies

Compliance: The Machinery Regulation defines the term and covers modifications by physical or digital means, including software. Changes foreseen and planned by the manufacturer, and repairs that do not change safety, are not substantial.
Assessment: Decide through impact analysis whether a change creates a new hazard or increases a risk, and whether that requires new protective measures, such as new guards or a modified safety-related control system. Document the reasoning either way. For the typical retrofit cases, see retrofit under the Machinery Regulation.
Technical documentation: After a substantial modification, the person responsible needs a technical file, conformity assessment, declaration of conformity and CE marking for the modified machinery, and updated instructions.
Before 2027: Directive 2006/42/EC does not define the term; national guidance fills the gap until the regulation applies. Independently of product law, an operator in Germany keeps its risk assessment under the BetrSichV current for every change.