Covering the installation life cycle
NR-10 covers electricity generation, transmission, distribution and consumption, from design through operation and maintenance. Work near electrical installations is also within its scope. It organises protective measures for people interacting directly or indirectly with electrical systems. An assessment of electrical risk must also consider concurrent hazards, including height, fire, moving equipment and environmental conditions. Electrical competence alone does not remove those additional risks.
Diagrams and the prontuário
Companies must retain updated single-line diagrams showing earthing arrangements and protective devices. Establishments with installed electrical load exceeding 75 kW must establish and maintain a Prontuário de Instalações Elétricas. This technical record includes procedures, inspection information, protective measures and personnel documentation. Further provisions apply to power-system installations and work close to them. Documents need to describe the equipment actually present rather than a superseded design.
Competence and authorisation
The standard distinguishes qualification, professional licensing, training and authorisation. A course attendance certificate does not establish that its holder may undertake every kind of electrical work. The organisation identifies authorised activities, the preparation required and the relevant working conditions. Technical documents in the prontuário must be prepared by legally qualified professionals. Responsibility for organising and keeping the record current must also be assigned within the business.
Measures applied to actual work
NR-10 gives priority to collective protection and addresses de-energisation within a controlled procedure. Where collective measures are technically unfeasible or insufficient, appropriate individual protection is added. An introductory article cannot provide a safe switching sequence for a particular installation: circuit identification, isolation, verification and restoration require suitable procedures, equipment and personnel. Signs and instructions must reflect the actual condition of the installation at the time of work.
A document-review example
A production line is expanded while its single-line diagram retains the earlier configuration. Review finds that the new circuit and its verification records are missing. Before maintenance is authorised, the discrepancies are corrected and responsibilities, protection and planning are reassessed. A large collection of files does not compensate for relevant documents describing an installation that no longer exists. Changes need to remain traceable to their supporting technical information.
What a useful check demonstrates
Connect each installation with its diagrams, reports, outstanding actions and authorised people. Confirm that affected workers can access the information they need. The threshold for a prontuário does not exempt smaller installations from electrical prevention: the requirements relevant to their activities and risks continue to apply.
