Sets mandatory technical rules for the design, execution and verification of all low-voltage electrical installations. Applies to every installation regardless of type. Amended by Portaria 252/2015.

Governs inspection, certification, registration and periodic oversight of private installations connected to the public grid. Amended by Lei 61/2018. Defines Type A, B and C installations and when inspections are required.

Mandatory 5-year periodic inspections apply to commercial premises, public venues, hospitals and schools — not standard residential properties. Confirmed by IEP: residential installations are explicitly excluded from this group.