{"id":72419,"date":"2026-08-21T22:25:25","date_gmt":"2026-08-22T01:25:25","guid":{"rendered":"https:\/\/a3aengenharia.com\/?post_type=articles&#038;p=72419"},"modified":"2026-08-21T22:25:25","modified_gmt":"2026-08-22T01:25:25","slug":"nbr-5419-4-2026-spm-lpz-spd-electrical-electronic-systems","status":"publish","type":"articles","link":"https:\/\/a3aengenharia.com\/en-us\/content\/technical-articles\/nbr-5419-4-2026-spm-lpz-spd-electrical-electronic-systems\/","title":{"rendered":"NBR 5419-4:2026: SPM, LPZ, SPDs and Protection of Electrical and Electronic Systems"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\"><strong>ABNT NBR 5419-4:2026<\/strong> establishes requirements for protecting electrical power and signal installations, and the equipment they serve, against damage caused by voltage and current surges associated with lightning. Part 4 works with two central concepts: <strong>Surge Protection Measures \u2014 SPM<\/strong> and <strong>Lightning Protection Zones \u2014 LPZ<\/strong>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The standard should not be reduced to a rule for \u201cinstalling SPDs.\u201d An SPD is only one possible measure. An SPM design may involve a coordinated SPD system, equipotential bonding, grounding, line routing, shielding, isolating interfaces, loop-area reduction, LPZ definition and coordination between power and signal-line protection. Device effectiveness depends on the architecture in which it is installed.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The 2026 edition also explicitly applies Part 4 to <strong>new lightning-protection designs and installations, refurbishment of existing systems, and changes in use, construction characteristics or electrical installations that affect protection<\/strong>. In an existing installation, therefore, the technical response is not simply to add SPDs to switchboards: the actual condition of the installation, available documentation, LPS, grounding system, equipotential bonding and the electrical\/electronic systems that require protection must be known.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The standard itself defines the <strong>lightning protection designer<\/strong> as a qualified professional with demonstrated technical competence. This is consistent with the nature of the problem: selecting, coordinating and locating protective measures requires engineering decisions that cannot be replaced by isolated component selection from a catalog.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What is NBR 5419-4:2026 and what is its scope?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The ABNT NBR 5419 series addresses lightning protection in an integrated manner. Part 4 focuses on <strong>electrical and electronic systems within structures<\/strong>, establishing requirements for protection against surges and electromagnetic effects associated with lightning.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Its scope includes:<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>design, installation, inspection and maintenance of SPM;<\/li><li>protective measures applicable to power and signal installations;<\/li><li>protection of equipment served by those installations;<\/li><li>surges induced in or directly applied to lines;<\/li><li>refurbishment and retrofits in existing structures;<\/li><li>installation changes that can modify protection conditions.<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Part 4 is not intended to protect the structure from the direct physical effects of lightning. That responsibility belongs mainly to Part 3. This boundary matters because a system may have an external LPS and still remain vulnerable to electronic failures caused by LEMP and conducted surges.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Lightning protection, external LPS, internal LPS and SPM: concepts that should not be confused<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The 2026 edition uses a useful conceptual architecture for design. <strong>Lightning Protection<\/strong> is the complete system, comprising the external LPS, internal LPS and SPM.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td>Element<\/td><td>Main function<\/td><\/tr><tr><td>External LPS<\/td><td>intercept lightning, conduct its current and disperse it into the earth through the air-termination, down-conductor and earth-termination subsystems<\/td><\/tr><tr><td>Internal LPS<\/td><td>minimize dangerous sparking and shock through lightning equipotential bonding and separation distance<\/td><\/tr><tr><td>SPM<\/td><td>protect internal systems against LEMP, surges and electromagnetic fields<\/td><\/tr><tr><td>Coordinated SPD system<\/td><td>set of SPDs selected, coordinated and installed to reduce failures of internal systems<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">This distinction prevents a recurrent error: using \u201cLPS\u201d as a synonym for all lightning protection or assuming that an SPD installed at the main switchboard completes the analysis.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The <a href=\"https:\/\/a3aengenharia.com.br\/conteudo\/artigos-tecnicos\/nbr-5419\/\">general article on NBR 5419 and LPS<\/a> addresses the series as a whole. Here the focus is Part 4 and protection of internal systems.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What are Surge Protection Measures \u2014 SPM?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">NBR 5419-4 defines SPM as the set of measures intended to protect internal systems against the effects of <strong>LEMP \u2014 lightning electromagnetic impulse<\/strong>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">These effects can arise through resistive, inductive and capacitive coupling. Protection therefore cannot be conceived merely as \u201cdiverting an overvoltage to earth.\u201d The design needs to control the paths by which energy and potential differences reach equipment.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Measures that may form part of SPM include:<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>equipotential bonding connections and networks;<\/li><li>coordinated SPD system;<\/li><li>spatial shielding;<\/li><li>line shielding;<\/li><li>proper cable routing;<\/li><li>loop-area reduction;<\/li><li>isolating interfaces;<\/li><li>separation and organization by LPZ;<\/li><li>coordinated protection of power and signal lines.<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">The appropriate combination depends on risk analysis, the structure, the installation and the sensitivity of internal systems.<\/p>\n\n\n\n<div class=\"wp-block-a3a-destaque\">\n<p class=\"wp-block-paragraph\"><strong>Protective measures need to be defined as a system, not as a list of SPDs.<\/strong><\/p>\n\n\n<p class=\"wp-block-paragraph\">The <a href=\"https:\/\/a3aengenharia.com.br\/servicos\/planejamento\/projeto-medidas-protecao-contra-surtos-mps\/\">Surge Protection Measures (SPM) Design<\/a> consolidates LPZ, equipotential bonding, grounding, power and signal lines, SPD classes, coordination and installation criteria based on the technical assessment of the building.<\/p>\n<\/div>\n\n\n\n<h2 class=\"wp-block-heading\">Lightning Protection Zones \u2014 LPZ \u2014 organize the architecture<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The LPZ concept divides the structure into zones subject to different levels of electromagnetic stress. As one moves into internal zones, the intention is to progressively reduce the intensity of surges and fields capable of reaching equipment.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This does not simply mean creating \u201cphysical areas\u201d in the design. An LPZ boundary has practical consequences: lines crossing it must be assessed; conductive parts may require bonding; SPDs, shielding or isolating interfaces may be required.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In a corporate building, for example, the power entrance, telecommunications entrance, a data center, an automation room and rooftop equipment may be associated with different exposure conditions. The SPM design must represent this architecture.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The content on <a href=\"https:\/\/a3aengenharia.com.br\/conteudo\/artigos-tecnicos\/zonas-protecao-contra-raios-definicao-segmentacao-ambientes-2\/\">Lightning Protection Zones \u2014 LPZ<\/a> discusses zone segmentation in depth.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Equipotential bonding is a structural part of protection<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">NBR 5419-4 defines equipotential bonding as the set of measures intended to reduce potential differences caused by lightning between metallic parts of installations to tolerable levels, while also contributing to reducing electric-shock risk.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This definition shows why <strong>SPDs without coherent equipotential bonding can perform far below expectations<\/strong>. The device creates a transient path between conductors. If the equipotential reference is inadequate, distant or formed by long inductive interconnections, the effective voltage at equipment terminals can remain high.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Main and local bonding bars, protective conductors, metallic elements and shields need to be analyzed within a single architecture. <a href=\"https:\/\/a3aengenharia.com.br\/conteudo\/artigos-tecnicos\/equipotencializacao-eletrica-nbr-5410\/\">Equipotential bonding<\/a> should be verified as a design condition, not as an optional accessory added after the SPDs.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Grounding: measuring electrode resistance alone is not enough<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Under the NBR 5419-4 definition, the grounding system includes earth electrodes, grounding conductors, protective conductors, equipotential bonding conductors and metallic parts that perform an equivalent function.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This is broader than asking \u201chow many ohms does the grounding system have?\u201d For SPM, transient current paths, equipotential bonding, lightning-current distribution, conductor configuration and relationships among PE, neutral, PEN and exposed conductive parts matter.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In low-voltage installations, the <strong>TN, TT or IT<\/strong> arrangement changes the way SPDs, neutral, PE and shock protection interact. Annex B of the 2026 edition explicitly includes the earthing arrangement at the power entrance among the data that must be collected for existing structures.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The <a href=\"https:\/\/a3aengenharia.com.br\/conteudo\/artigos-tecnicos\/aterramento-eletrico-fundamentos-tipos-e-importancia-para-a-protecao-dos-sistemas-eletricos\/\">electrical grounding article<\/a> discusses these arrangements in depth. In an SPM design, they should be checked against actual field conditions and available documentation.<\/p>\n\n\n\n<div class=\"wp-block-a3a-destaque\">\n<p class=\"wp-block-paragraph\"><strong>Is the existing grounding system known only from a resistance measurement?<\/strong><\/p>\n\n\n<p class=\"wp-block-paragraph\">Surge protection also requires checking PE, PEN, main\/local bonding bars, continuity, equipotential bonding, geometry and LPS integration. The <a href=\"https:\/\/a3aengenharia.com.br\/servicos\/planejamento\/projeto-de-aterramento\/\">Grounding Design<\/a> treats this infrastructure as a system and provides the basis for correct SPM operation.<\/p>\n<\/div>\n\n\n\n<h2 class=\"wp-block-heading\">SPDs in NBR 5419-4: a coordinated system, not isolated devices<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The standard defines a <strong>coordinated SPD system<\/strong> as SPDs that are properly selected, coordinated and installed and that, individually or together, minimize failures caused by lightning in internal systems.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The word \u201ccoordinated\u201d is decisive. Two or three SPDs installed in different switchboards do not automatically form a coordinated system. Stress at each point, protection level, distance between stages, residual energy, equipment withstand and connection paths must be assessed.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The article on <a href=\"https:\/\/a3aengenharia.com.br\/conteudo\/artigos-tecnicos\/coordenacao-selecao-dps-instalacoes-eletricas-2\/\">cascaded SPD coordination<\/a> is the dedicated content for details of energy coordination, Up\/f, \u0394U, Uw and distances. Here, the central point is that NBR 5419-4 places this coordination within the broader SPM design.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Up, Up\/f and Uw: effective protection voltage matters<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">NBR 5419-4 distinguishes the <strong>Up<\/strong> protection level declared for the SPD from the effective protection level <strong>Up\/f<\/strong>, which includes voltage drops in the device&#8217;s connecting conductors in the installation.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This difference explains why an SPD with excellent laboratory Up can protect equipment poorly when installed with long conductors, loops or unsuitable routes.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Equipment withstand, expressed by <strong>Uw<\/strong> where applicable, must be compared with the level actually imposed at the protected point. In design, this leads to three questions:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">1. what is the equipment or system withstand? 2. what is the Up of the selected SPD? 3. what will the Up\/f be considering the actual installation?<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The answer does not come from the SPD label alone. It requires drawings, location and verification of connections.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Class I, Class II and prospective current at the point<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">SPD classification is related to test conditions and expected stress. SPDs tested with <strong>Iimp<\/strong> correspond to Class I; those tested with <strong>In<\/strong> correspond to Class II; Class III uses a combination wave.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In an architecture associated with an LPS, a boundary exposed to part of the lightning current may require an SPD capable of conducting impulse current. Other points may be exposed predominantly to induced or residual surges.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Selection should therefore not start from the statement \u201cClass I is better than Class II.\u201d It should start from the <strong>prospective current at the SPD<\/strong>, sources of damage, LPZ boundary location and the function of that stage.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The differences among <a href=\"https:\/\/a3aengenharia.com.br\/conteudo\/artigos-tecnicos\/dps-classe-1-classe-2-classe-3\/\">Class 1, Class 2 and Class 3 SPDs<\/a> are discussed in the dedicated article.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Power and signal lines belong to the same design<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The 2026 edition defines an electrical line as a power or signal line entering or leaving the structure. Signal lines include telecommunications, data exchange, control and automation.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This is particularly important because many designs protect only electrical switchboards. An outdoor camera, antenna, Ethernet network between buildings, automation signal or telephone line can introduce another metallic interface capable of carrying surges.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">At relevant boundaries, protection should assess <strong>all lines<\/strong>. NBR 5419-4 also cites isolating interfaces as a resource capable of blocking conducted surges.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The article <a href=\"https:\/\/a3aengenharia.com.br\/conteudo\/artigos-tecnicos\/dps-linhas-dados-cftv-automacao-telecom\/\">SPDs for data lines, CCTV, automation and telecommunications<\/a> discusses transmission criteria, Ethernet\/PoE, CCTV, serial networks and metallic interfaces in depth.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Shielding, routing and loop area<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Lightning effects are not only conducted. Magnetic fields can induce voltages and currents in loops formed by installations.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Part 4 presents methods for assessing shielding and induced voltages. In practical terms, the design should consider:<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>width and continuity of shielding meshes;<\/li><li>distance of circuits from shields;<\/li><li>joint or separate conductor routing;<\/li><li>loop area among power, signal and reference paths;<\/li><li>continuity of metallic structures used as shielding;<\/li><li>connection of shields to the equipotential bonding network.<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">The 2026 edition even notes that an equipotential bonding mesh can reduce the magnetic field under certain conditions. The physical infrastructure design therefore contributes to SPM performance.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What does NBR 5419-4:2026 require for existing structures?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Annex B<\/strong> is particularly relevant to retrofit and adaptation. It recognizes that in an existing structure it is not always feasible to apply every measure as it would be conceived in a new design, but it requires selection to be based on actual conditions.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The standard recommends developing a study to determine protection zones, grounding, equipotential bonding, line routing and shielding. It also proposes a set of checks covering the structure, installation and equipment.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Information to collect includes:<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td>Group<\/td><td>Examples of information<\/td><\/tr><tr><td>Structure<\/td><td>construction material, reinforcement, metallic fa\u00e7ades, roof, existing LPS, soil<\/td><\/tr><tr><td>Installation<\/td><td>power and signal entrances, HV\/MV\/LV supply, antennas, ducts, routing and shielding<\/td><\/tr><tr><td>Interconnections<\/td><td>metallic cables to other structures and external equipment<\/td><\/tr><tr><td>Equipment<\/td><td>analog\/digital interfaces, balanced or unbalanced, coaxial, pairs, fiber, withstand<\/td><\/tr><tr><td>Grounding<\/td><td>TN\/TN-S\/TN-C, TT or IT arrangement and functional earthing connections<\/td><\/tr><tr><td>Equipotential bonding<\/td><td>main\/local bonding bars, bonding network, exposed conductive parts and interconnected metallic parts<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">This survey is very close to a <strong>technical due diligence of the installation<\/strong>. It shows why an SPD retrofit in a brownfield installation should not begin with purchasing components.<\/p>\n\n\n\n<div class=\"wp-block-a3a-destaque\">\n<p class=\"wp-block-paragraph\"><strong>Is the installation existing and are actual SPM conditions undocumented?<\/strong><\/p>\n\n\n<p class=\"wp-block-paragraph\">Before defining new SPDs, the LPS, grounding, equipotential bonding, power and signal entrances, routes, shielding and interfaces need to be surveyed. The <a href=\"https:\/\/a3aengenharia.com.br\/servicos\/levantamento-e-diagnostico\/inspecao-diagnostico-adequacao-dps-mps\/\">Inspection, Diagnosis and Retrofit of SPDs and SPM<\/a> converts existing conditions into a technical basis for the retrofit design.<\/p>\n<\/div>\n\n\n\n<h2 class=\"wp-block-heading\">Design sequence for SPM in an existing installation<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The flowchart in Annex B organizes the process logically:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">1. obtain data on the structure and installations; 2. perform risk analysis according to NBR 5419-2; 3. decide whether SPM are required; 4. define the LPZ; 5. design the basic equipotential bonding system; 6. design measures for each LPZ; 7. design a coordinated SPD system; 8. assess additional measures; 9. address external equipment and interconnections between structures; 10. document the solution and verify its installation.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This sequence is incompatible with an approach based on \u201chow many SPDs should I install in the switchboard?\u201d The number of devices is a consequence of the design.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">When existing conditions are unknown, an <a href=\"https:\/\/a3aengenharia.com.br\/servicos\/levantamento-e-diagnostico\/inspecao-diagnostico-adequacao-dps-mps\/\">Inspection, Diagnosis and Retrofit of SPDs and SPM<\/a> can precede design, providing an inventory, evidence and a nonconformity matrix.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Changes in use or installation may require reassessment<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The 2026 edition explicitly applies when lightning protection already exists and changes in use, construction characteristics or electrical installation can affect that protection.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This matters in expansions, retrofits, changes of occupancy, installation of new electronic equipment, switchboard changes, photovoltaic generation, data centers, automation or new external lines.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In these cases, it should not be assumed that the existing system remains adequate merely because an old design exists. Engineering must check the impact of the change on risk analysis, LPZ, equipotential bonding, current paths and SPM.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Electrical design and NBR 5410 remain essential<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">NBR 5419-4 references <strong>ABNT NBR 5410<\/strong>. This reinforces that SPM design does not replace low-voltage installation design.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">NBR 5410 addresses earthing arrangements, shock protection, overcurrent, RCDs, SPD location and connection, conductor cross sections and installation requirements. Part 4 adds the layer of protection against LEMP and lightning.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In a real retrofit, corrections may be required in the switchboard itself: busbars, N\/PE separation, backup protection, short-circuit capability, conductors, RCDs, identification or selectivity. <strong>There is no SPD design independent of the electrical conditions of the switchboard in which it will be installed.<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">When infrastructure needs review, the <a href=\"https:\/\/a3aengenharia.com.br\/servicos\/planejamento\/projeto-eletrico-baixa-tensao\/\">Low-Voltage Electrical Design<\/a> should be coordinated with the SPM design.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">The SPM design should produce verifiable documentation<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">A sound engineering solution needs to be verifiable in the field. Depending on complexity, the design should record:<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>adopted criteria and assumptions;<\/li><li>document review and as-existing survey;<\/li><li>LPZ and their boundaries;<\/li><li>equipotential bonding architecture;<\/li><li>SPD installation points;<\/li><li>classes, Uc, Up, Up\/f, In, Iimp and other applicable parameters;<\/li><li>backup protection and interfaces with RCDs;<\/li><li>conductors and connection details;<\/li><li>protected signal lines;<\/li><li>shielding, routing and isolating interfaces;<\/li><li>relationship with external and internal LPS;<\/li><li>specifications and acceptance criteria;<\/li><li>drawings, diagrams, design reports and bills of materials.<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">The installation should be inspected and commissioned against this documentation. Without this reference, it is difficult to demonstrate whether the system actually corresponds to the designed solution.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Inspection and maintenance are also part of Part 4<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The scope of NBR 5419-4 covers design, installation, inspection and maintenance of SPM. Protection therefore does not end at project handover.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">SPDs have an operating state and may degrade or disconnect. Interconnections may be changed. Switchboards may receive new circuits. Data cables may be rerouted. Electronic systems may be replaced with equipment having different withstand characteristics.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Maintenance needs to preserve design assumptions and update documentation when the installation changes. An SPD replaced by a \u201csimilar\u201d unit may alter Uc, Up, discharge capacity or coordination.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Installing SPDs is not enough: SPM is an engineering design<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The main practical conclusion from NBR 5419-4:2026 is that protection of internal systems must be conceived as a <strong>system<\/strong>. The standard integrates risk, LPZ, grounding, equipotential bonding, power lines, signal lines, shielding, routing, interfaces and coordinated SPDs.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">An installation with several SPDs can therefore remain poorly protected if devices are located incorrectly, referenced to inadequate equipotential bonding, connected by long conductors, incompatible with the TN\/TT\/IT arrangement or disconnected from the LPS architecture.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In existing installations, the technically consistent path is <strong>survey \u2192 diagnose \u2192 analyze \u2192 design \u2192 retrofit \u2192 commission \u2192 document<\/strong>. Installing SPDs is only one stage in this process.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The <a href=\"https:\/\/a3aengenharia.com.br\/servicos\/planejamento\/projeto-medidas-protecao-contra-surtos-mps\/\">Surge Protection Measures \u2014 SPM Design<\/a> organizes these decisions into a documented solution coordinated with electrical design, grounding, equipotential bonding and LPS.<\/p>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary>Technical references<\/summary>\n<p class=\"wp-block-paragraph\">[1] ABNT. <a href=\"https:\/\/www.abntcatalogo.com.br\/\">ABNT NBR 5419-4:2026 \u2014 Protection against lightning \u2014 Part 4: Electrical and electronic systems within structures<\/a>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">[2] ABNT. <a href=\"https:\/\/www.abntcatalogo.com.br\/\">ABNT NBR 5410:2004 \u2014 Low-voltage electrical installations<\/a>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">[3] IEC. <a href=\"https:\/\/webstore.iec.ch\/\">IEC 61643 series \u2014 Low-voltage surge protective devices<\/a>.<\/p>\n<\/details>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary>Frequently asked questions<\/summary>\n<div class=\"schema-faq wp-block-yoast-faq-block\"><div class=\"schema-faq-section\" id=\"faq-question-o-que-a-nbr-5419-4-2026-trata-3eea8f54\"><strong class=\"schema-faq-question\">What does NBR 5419-4:2026 cover?<\/strong> <p class=\"schema-faq-answer\">Part 4 establishes requirements for protecting electrical power and signal installations and equipment against surges associated with lightning, using SPM and LPZ concepts.<\/p><\/div><div class=\"schema-faq-section\" id=\"faq-question-a-nbr-5419-4-exige-apenas-instalar-dps-a5f4d983\"><strong class=\"schema-faq-question\">Does NBR 5419-4 only require installing SPDs?<\/strong> <p class=\"schema-faq-answer\">No. SPDs are one of the measures. The design may involve equipotential bonding, grounding, shielding, routing, isolating interfaces, LPZ and a coordinated SPD system.<\/p><\/div><div class=\"schema-faq-section\" id=\"faq-question-spda-externo-substitui-as-mps-98fd0a06\"><strong class=\"schema-faq-question\">Does an external LPS replace SPM?<\/strong> <p class=\"schema-faq-answer\">No. The external LPS reduces physical damage associated with direct lightning; SPM protect internal systems against LEMP and surges. Both are part of the complete lightning-protection architecture.<\/p><\/div><div class=\"schema-faq-section\" id=\"faq-question-uma-instala-o-existente-precisa-ser-levantada-an-9890fb87\"><strong class=\"schema-faq-question\">Does an existing installation need to be surveyed before SPM design?<\/strong> <p class=\"schema-faq-answer\">Yes, when conditions are not sufficiently documented. Annex B of NBR 5419-4:2026 provides for surveying the structure, power and signal systems, grounding, equipment, routing, shielding and interconnections as a design basis.<\/p><\/div><div class=\"schema-faq-section\" id=\"faq-question-aterramento-e-equipotencializa-o-interferem-na-p-bc3d165a\"><strong class=\"schema-faq-question\">Do grounding and equipotential bonding affect SPD protection?<\/strong> <p class=\"schema-faq-answer\">Yes. They define transient-current references and paths. An SPD installed without a coherent grounding and equipotential-bonding architecture may fail to provide the expected protection level.<\/p><\/div><div class=\"schema-faq-section\" id=\"faq-question-altera-es-na-instala-o-el-trica-podem-exigir-rev-d6ce0d94\"><strong class=\"schema-faq-question\">Can changes to the electrical installation require a review of lightning protection?<\/strong> <p class=\"schema-faq-answer\">Yes. The 2026 edition explicitly applies when changes in use, construction characteristics or electrical installation affect existing protection.<\/p><\/div><\/div>\n<\/details>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary>Complementary technical materials<\/summary>\n\n<h3 class=\"wp-block-heading\">Related solutions<\/h3>\n\n\n<ul class=\"wp-block-list\"><li><a href=\"https:\/\/a3aengenharia.com.br\/solucoes\/engenharia-eletrica\/medidas-de-protecao-contra-surtos\/\">Surge Protection Measures (SPM)<\/a><\/li><li><a href=\"https:\/\/a3aengenharia.com.br\/solucoes\/engenharia-eletrica\/dispositivos-de-protecao-contra-surtos\/\">Surge Protective Devices (SPDs)<\/a><\/li><li><a href=\"https:\/\/a3aengenharia.com.br\/solucoes\/engenharia-eletrica\/aterramento-eletrico\/\">Grounding and Equipotential Bonding<\/a><\/li><li><a href=\"https:\/\/a3aengenharia.com.br\/solucoes\/engenharia-eletrica\/infraestrutura-eletrica-de-baixa-tensao\/\">Low-Voltage Electrical Infrastructure<\/a><\/li><\/ul>\n\n\n<h3 class=\"wp-block-heading\">Related engineering services<\/h3>\n\n\n<ul class=\"wp-block-list\"><li><a href=\"https:\/\/a3aengenharia.com.br\/servicos\/planejamento\/projeto-medidas-protecao-contra-surtos-mps\/\">Surge Protection Measures (SPM) Design<\/a><\/li><li><a href=\"https:\/\/a3aengenharia.com.br\/servicos\/levantamento-e-diagnostico\/inspecao-diagnostico-adequacao-dps-mps\/\">Inspection, Diagnosis and Retrofit of SPDs and SPM<\/a><\/li><li><a href=\"https:\/\/a3aengenharia.com.br\/servicos\/planejamento\/projeto-de-aterramento\/\">Grounding Design<\/a><\/li><li><a href=\"https:\/\/a3aengenharia.com.br\/servicos\/planejamento\/projeto-de-sistema-de-protecao-contra-descargas-atmosfericas\/\">LPS Design<\/a><\/li><li><a href=\"https:\/\/a3aengenharia.com.br\/servicos\/planejamento\/projeto-eletrico-baixa-tensao\/\">Low-Voltage Electrical Design<\/a><\/li><\/ul>\n\n\n<h3 class=\"wp-block-heading\">Related technical content<\/h3>\n\n\n<ul class=\"wp-block-list\"><li><a href=\"https:\/\/a3aengenharia.com.br\/conteudo\/artigos-tecnicos\/coordenacao-selecao-dps-instalacoes-eletricas-2\/\">SPD Coordination: Cascading, Energy, Up\/f and Equipment Protection<\/a><\/li><li><a href=\"https:\/\/a3aengenharia.com.br\/conteudo\/artigos-tecnicos\/dps-linhas-dados-cftv-automacao-telecom\/\">SPDs for Data Lines, CCTV, Automation and Telecommunications<\/a><\/li><li><a href=\"https:\/\/a3aengenharia.com.br\/conteudo\/artigos-tecnicos\/equipotencializacao-eletrica-nbr-5410\/\">Equipotential Bonding<\/a><\/li><li><a href=\"https:\/\/a3aengenharia.com.br\/conteudo\/artigos-tecnicos\/aterramento-eletrico-fundamentos-tipos-e-importancia-para-a-protecao-dos-sistemas-eletricos\/\">Electrical Grounding: Function, Types, NBR 5410, SPDs and LPS<\/a><\/li><li><a href=\"https:\/\/a3aengenharia.com.br\/conteudo\/artigos-tecnicos\/nbr-5419\/\">NBR 5419: LPS, Risk Analysis, Grounding and SPDs<\/a><\/li><\/ul>\n\n\n<h3 class=\"wp-block-heading\">Guides and references<\/h3>\n\n\n<ul class=\"wp-block-list\"><li><a href=\"https:\/\/a3aengenharia.com.br\/conteudo\/guias-tecnicos\/guia-completo-sobre-spda-e-mps\/\">Complete Guide to Lightning Protection (LPS + SPM)<\/a><\/li><li><a href=\"https:\/\/a3aengenharia.com.br\/conteudo\/guias-tecnicos\/guia-completo-sobre-instalacoes-eletricas-de-baixa-tensao\/\">Complete Guide to Low-Voltage Electrical Installations<\/a><\/li><li><a href=\"https:\/\/a3aengenharia.com.br\/conteudo\/whitepapers\/whitepaper-metodo-projeto-dimensionamento-instalacoes-eletricas-baixa-tensao\/\">Low-Voltage Electrical Installation Design and Sizing Method<\/a><\/li><li><a href=\"https:\/\/a3aengenharia.com.br\/conteudo\/ebooks\/aterramento-eletrico\/\">Electrical Grounding: Fundamentals, Design and Standards<\/a><\/li><\/ul>\n\n<\/details>\n","protected":false},"excerpt":{"rendered":"<p>Technical guide to NBR 5419-4:2026 applied to SPM, LPZ, coordinated SPDs, grounding, equipotential bonding, power and signal lines, retrofit, inspection and design.<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"template":"","meta":{"_a3a_global_related_solutions":[],"_a3a_global_related_services":[],"_a3a_global_related_materials":[],"_a3a_post_lang":"en-us","_a3a_translation_group_id":"e764e635-65b8-497e-811e-2e740375aa34","_a3a_i18n_canonical_slug":"nbr-5419-4-2026-spm-lpz-spd-electrical-electronic-systems"},"categories":[],"segments":[],"mercados":[],"etapas":[],"class_list":["post-72419","articles","type-articles","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/a3aengenharia.com\/en-us\/wp-json\/wp\/v2\/articles\/72419","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/a3aengenharia.com\/en-us\/wp-json\/wp\/v2\/articles"}],"about":[{"href":"https:\/\/a3aengenharia.com\/en-us\/wp-json\/wp\/v2\/types\/articles"}],"author":[{"embeddable":true,"href":"https:\/\/a3aengenharia.com\/en-us\/wp-json\/wp\/v2\/users\/1"}],"version-history":[{"count":1,"href":"https:\/\/a3aengenharia.com\/en-us\/wp-json\/wp\/v2\/articles\/72419\/revisions"}],"predecessor-version":[{"id":72429,"href":"https:\/\/a3aengenharia.com\/en-us\/wp-json\/wp\/v2\/articles\/72419\/revisions\/72429"}],"wp:attachment":[{"href":"https:\/\/a3aengenharia.com\/en-us\/wp-json\/wp\/v2\/media?parent=72419"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/a3aengenharia.com\/en-us\/wp-json\/wp\/v2\/categories?post=72419"},{"taxonomy":"segments","embeddable":true,"href":"https:\/\/a3aengenharia.com\/en-us\/wp-json\/wp\/v2\/segments?post=72419"},{"taxonomy":"mercados","embeddable":true,"href":"https:\/\/a3aengenharia.com\/en-us\/wp-json\/wp\/v2\/mercados?post=72419"},{"taxonomy":"etapas","embeddable":true,"href":"https:\/\/a3aengenharia.com\/en-us\/wp-json\/wp\/v2\/etapas?post=72419"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}