NEN 3140

Current edition & highlights (A3)

• Current definitive edition: NEN 3140:2011+A3:2019.
• A3 clarifies arc-flash topics: procedures, PPE and determining incident energy at the workplace.
• Ensure a risk-based approach: task risk assessment, permits to work, lock-out/tag-out and isolation; clear IV/WV/VP/VOP roles.
• NEN 3140 is based on NEN-EN 50110 and contains the relevant Dutch provisions; record risk-based inspection intervals in the management plan.

Safe work & authorisations

• Roles: Installation Responsible Person (IV), Work Responsible Person (WV), Skilled Person (VP) and Instructed Person (VOP).
• Procedures: de-energised work, lock-out/tag-out, PPE, barriers and signage.
• Task/risk assessment (TRA/JSA), permit to work and release for service.

Management & periodic inspections

• Management plan with risk-based inspection intervals (environment, use, history).
• Measurements/tests appropriate to operations (e.g. RCD test, impedance; thermography where useful).
• Register findings, priorities and corrective actions.

What does an inspection performed in accordance with NEN 3140 deliver?

• A clear scope: which rooms, distribution boards, installation parts and work equipment were assessed.
• Visual findings and measurements, prioritised by risk so corrective work is actionable.
• Advice on inspection intervals, management arrangements and IV/WV/VP/VOP authorisations where these are missing.
• Note: NEN lists a draft NEN 3140:2026 Ontw.; it only replaces the current edition once the new standard is formally published.

Documentation & training

Maintain up-to-date schematics, component data, authorisations and work instructions; ensure training for staff and contractors.

Frequently asked questions