What NBR 5410, NBR 5419, NR-10 and NR-35 actually require of you

NBR 5410 — Low-voltage electrical installations

The parent standard for building and industrial electrical design in low voltage: up to 1,000 V AC (and 1,500 V DC) below 400 Hz. The current published edition is still 2004 with amendments, and a full revision has been under way at ABNT since 2023 — so a properly built design today is already compatible with the new structure.

• Design is a requirement: the installation must be designed, built, verified and maintained by a qualified professional, with single-line diagram, specifications, layout drawings and a load schedule.
• Sizing: conductor cross-section by installation method, grouping and correction factors, voltage drop inside limits and short-circuit thermal stress verification.
• Shock protection: automatic disconnection (fuse/breaker) plus 30 mA RCD mandatory for wet areas, bathrooms, kitchens, outdoor circuits and general-purpose socket outlets, per the standard rule.
• Earthing and bonding: TN, TT or TN-C-S scheme defined in the design, continuous protective conductor, main and supplementary equipotential bonding (the item most often flagged in older buildings).
• Initial verifications: PE continuity, insulation resistance, polarity, RCD trip test and circuit identification — the same tests that later become the table in the technical report.

NBR 5419 — Protection against atmospheric discharges (replaced NBR 5418)

Anyone asking for an "NBR 5418 report" is citing the obsolete lightning-rod standard: it was withdrawn and replaced by the NBR 5419 series (harmonized with IEC 62305). The 2026 edition cancelled the 2015 one and changed criteria that directly affect reports and re-inspection.

• Risk analysis decides whether an LPS is mandatory — not comfort: the standard computes tolerable loss and sets the protection level (I to IV).
• Inspection interval by risk (clause 7.3.2): every 1 year for high-risk structures (classified areas, explosive atmospheres, essential services, severe coastal or industrial corrosion) and every 3 years for all others.
• Grounding efficacy changed (clause 7.1.4): the 2026 edition drops the old "must read under 10 Ω" verdict and now verifies electrical continuity with a milli-ohmmeter. A report based on the 2015 edition can be technically outdated even while still in date.
• Direct strike, SPD operation, retrofit or repair are triggers: in those events the standard requires a new inspection before the periodic interval ends.
• Report with ART and photo record: air-termination, down conductors, test connections, mesh, bonding and SPD condition — what fire marshals, city halls and insurers accept.

NR-10 — Safety in electrical installations and services

A Ministry of Labour regulation (CLT-based) covering anyone who interacts, directly or indirectly, with an electrical installation. The wording applied today remains in force until 31 May 2027; the fifth revision, Ordinance MTE 737 dated 29 May 2026, takes effect on 1 June 2027, with a specific term for existing installations.

• Electrical installation register (item 10.2.4): mandatory for premises with installed load above 75 kW — designs, single-line diagrams, inspection reports, permits to work and training evidence.
• De-energization is a procedure, not an intention: disconnection, prevention of re-energization (lockout/tagout), verification of absence of voltage, temporary equipotential bonding and signage.
• Training and personnel classification: NR-10 course with the minimum hours set by the standard, refresher every two years, and the distinction between trained, qualified, skilled and authorized workers — only the authorized one intervenes.
• Task risk analysis and written work procedure per installation, with control measures, PPE and collective protections inventoried and inspected.
• Risk management aligned with NR-1 (GRO/PGR): the 2026 revision reinforces electrical risk inside the company risk inventory — those with a PGR must add electricity, those without must start with NR-10.

See the report that feeds the register

NR-35 — Work at height

Applies to any activity above 2 metres from the lower level with fall risk: roof, LPS mast, high bay lighting, gutters, solar array, busbar rack. In electrical work, NR-10 and NR-35 apply at the same time.

• 8-hour initial training with practical exercise plus biennial reassessment, and fitness certified by a medical statement compatible with the task.
• Risk analysis and permit to work (PT) before going up, with recorded and signed control measures.
• Fall protection system: full-body harness, double lanyard with shock absorber, engineered anchorage point and life line — anchorage designed, never clipped to "whatever is there".
• Supervision and no isolated work without communication: someone accountable for the operation and for rescue.
• Emergency and rescue plan, including the suspended-worker scenario (suspension trauma) — and, with live conductors nearby, the NR-10 disconnection.

NBR 14039 — Medium-voltage installations (above 1 kV up to 36.2 kV)

The standard for the industrial power entry, transformer, switchgear cubicle and medium-voltage feeder. It shows up in the utility design, in commissioning and in the report that releases operation.

• Design with protection coordination and selectivity: relays, fuses, reclosers coordinated so only the faulted section is isolated.
• Insulation and clearances: withstand levels, minimum air distances, barriers and enclosures by voltage class.
• Earthing and fault currents: fault-current calculation, surface potential gradient and human-safety criteria.
• Commissioning and documented switching: insulation tests, turns ratio, relay functionality and recorded switching sequence.
• The human side: only skilled, authorized personnel operate medium voltage, with arc-flash PPE and a written procedure (NR-10).

NBR 17019 — Electric vehicle charging infrastructure

A 2022 standard created because "anyhow" installed chargers became a real hazard. It governs the fixed charging point: circuit, protection, identification and safety, including condominiums.

• Dedicated circuit with its own protection for each charging point, sized on the charger real current.
• Surge protection (SPD) mandatory at the charging point — the item improvised installs almost never have.
• Visible, identifiable disconnecting means next to the point, to cut power safely during maintenance or emergency.
• Interface with NBR 5410: a charger is a new load, so demand, conductor size, panel and RCD must be re-evaluated.
• Documentation and ART so the assembly, the insurer and the utility accept the installation.

See green energy and charging solutions

Law 5.194/1966 and CONFEA/CREA resolutions — who signs and with which document

The legal basis of the profession: it requires council registration and gives every technical work a named responsible person. This is what turns your design and your report into a valid document.

• Professional registration at the CREA of the jurisdiction is what enables the technical lead to sign.
• ART (Technical Responsibility Record) per work or service — design, execution, inspection, report and maintenance each need one.
• Scope by level and modality (CONFEA Resolution 218/1991): check that the ART object matches the work you contracted.
• Registered technical portfolio: the record that proves experience in audits, tenders and expert witness work.
• Without ART the report is void: fire marshals, city halls, insurers and utilities may refuse an unregistered document.

See certifications and registrations