{"id":2672,"date":"2026-09-20T15:28:32","date_gmt":"2026-09-20T07:28:32","guid":{"rendered":"https:\/\/www.britecelectric.com\/?post_type=blog&p=2672"},"modified":"2026-09-28T17:22:24","modified_gmt":"2026-09-28T09:22:24","slug":"electric-spd-type-1-applications-in-electrical-systems","status":"publish","type":"blog","link":"https:\/\/www.britecelectric.com\/it\/blog\/electric-spd-type-1-applications-in-electrical-systems\/","title":{"rendered":"Electric SPD Type 1 Applications In Electrical Systems"},"content":{"rendered":"

What Is an Electric SPD Type 1?<\/h2>\r\n

UN electric SPD Type 1<\/strong> \u2014 also called a Class I surge protective device<\/strong> \u2014 is installed at the origin of an electrical installation, typically the main incoming supply, to discharge the partial lightning current (Iimp) that can enter a building through power lines when an external lightning protection system (LPS) is present. Rated by their Iimp withstand per pole (commonly 12.5\u202fkA, 25\u202fkA or 50\u202fkA per IEC\u202f61643-11), Type\u202f1 devices are built for the high-energy impulses a direct or nearby lightning strike can inject into the grid.<\/p>\r\n

For B2B buyers, panel builders and electrical engineers, a Type\u202f1 SPD is the first line of defence at the service entrance. It protects the whole installation and the downstream Type\u202f2 and Type\u202f3 devices that handle smaller, induced surges.<\/p>\r\n\r\n

Type 1 vs Type 2 vs Type 3 SPD \u2014 Where Each Belongs<\/h2>\r\n

Surge protective devices are classified by the surge they must withstand. The table below shows how a Type\u202f1 SPD<\/strong> differs from Type\u202f2 and Type\u202f3 in tested impulse and installation point.<\/p>\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n
Tipo<\/th>\r\nTested Impulse<\/th>\r\nTypical Installation Point<\/th>\r\n<\/tr>\r\n
Type 1 (Class I)<\/strong><\/td>\r\nIimp \u2014 direct lightning current (10\/350\u202f\u03bcs)<\/td>\r\nMain incoming supply \/ service entrance<\/td>\r\n<\/tr>\r\n
Type 2 (Class II)<\/strong><\/td>\r\nIn \u2014 induced \/ switched surges (8\/20\u202f\u03bcs)<\/td>\r\nDistribution boards \/ sub-panels<\/td>\r\n<\/tr>\r\n
Type 3 (Class III)<\/strong><\/td>\r\nCombination wave \u2014 fine protection<\/td>\r\nClose to sensitive equipment \/ sockets<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n

Electric SPD Type 1 Applications In Electrical Systems<\/h2>\r\n

Because a Type\u202f1 SPD<\/strong> is designed to take a direct lightning current, it is specified wherever the incoming supply can carry that energy. The most common Type\u202f1 SPD applications in electrical systems<\/strong> include:<\/p>\r\n

\u25cf Main distribution boards and service entrances<\/strong> \u2014 the primary point where the utility supply enters a building.<\/p>\r\n

\u25cf Buildings with an external lightning protection system (LPS)<\/strong> \u2014 where air terminals and down-conductors can inject lightning current into the power lines.<\/p>\r\n

\u25cf Industrial plants and factories<\/strong> \u2014 process lines, motor control centres and large connected loads exposed to switching and lightning overvoltage.<\/p>\r\n

\u25cf Commercial buildings, hospitals and data centres<\/strong> \u2014 sites where a single surge can halt critical operations and damage expensive electronics.<\/p>\r\n

\u25cf PV and renewable-energy inverters<\/strong> \u2014 exposed structures where DC and AC sides both need coordinated protection.<\/p>\r\n

\u25cf Railway, telecom and utility infrastructure<\/strong> \u2014 long exposed conductors that act as lightning collectors.<\/p>\r\n

\u25cf Critical electrical loads<\/strong> \u2014 any installation where downtime from a surge is unacceptable (see SPD protection for critical electrical loads<\/a>).<\/p>\r\n\r\n

Where to Install a Type 1 SPD in the Distribution Chain<\/h2>\r\n

A Type\u202f1 SPD<\/strong> is mounted at the origin of the installation, ahead of the main breaker, so it intercepts the lightning current before it reaches downstream circuits. It is almost always used as the first stage of a coordinated cascade: Type\u202f1 at the entrance, Type\u202f2 at distribution boards, and Type\u202f3 at the equipment. Proper coordination keeps each stage from overloading the next \u2014 Britec covers this in the Type\u202f1 lightning surge protection device category<\/a> and in our cascade guides.<\/p>\r\n

A dedicated backup protector (surge protective device coordinator, or SCB) is recommended on the upstream side of a Type\u202f1 SPD. It isolates a faulted SPD without tripping the main supply \u2014 Britec offers Class\u202fI dedicated backup protectors such as the BRSCB-I series for this role.<\/p>\r\n\r\n

How to Select a Type 1 SPD for Your Project<\/h2>\r\n

When specifying a Type\u202f1 SPD<\/strong>, match the device to the system and the expected exposure:<\/p>\r\n

\u25cf Iimp rating<\/strong> \u2014 12.5\u202fkA, 25\u202fkA or 50\u202fkA per pole, chosen from the risk assessment of direct-strike exposure.<\/p>\r\n

\u25cf Livello di protezione della tensione (Su)<\/strong> \u2014 keep it at or below the impulse withstand of the protected equipment.<\/p>\r\n

\u25cf System configuration<\/strong> \u2014 TNS, TNC-S or TT, and the required pole count (1P+N, 3P, 4P).<\/p>\r\n

\u25cf Status indication and remote signalling<\/strong> \u2014 for preventive maintenance in unmanned sites.<\/p>\r\n

\u25cf Standards and certification<\/strong> \u2014 compliant with IEC\u202f61643-11 \/ EN\u202f61643-11 and backed by third-party marks.<\/p>\r\n\r\n

Why Specify Britec Electric Type 1 SPDs<\/h2>\r\n

Britec Electric Wenzhou Co., Ltd. has manufactured surge protective devices since 2003 and supplies panel builders, distributors and EPC contractors worldwide. Our Type\u202f1 SPDs<\/strong> are certified by Intertek SEMKO, T\u00dcV and CE, and are engineered for the high Iimp demands of service-entrance protection. Three representative models are shown below.<\/p>\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n
Model<\/th>\r\nIimp per pole<\/th>\r\nConfigurazione<\/th>\r\n<\/tr>\r\n
BR-25M 4P Type 1 25kA Surge Arrester<\/td>\r\n25\u202fkA<\/td>\r\n4P, TNS<\/td>\r\n<\/tr>\r\n
BR-50GR 4P Type 1 50kA Surge Arrester<\/td>\r\n50\u202fkA<\/td>\r\n4P, TNS<\/td>\r\n<\/tr>\r\n
Protettore da sovratensione BR-25VG 4P 25kA T1<\/td>\r\n25\u202fkA<\/td>\r\n4P, TNS<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n

Product photos (white background, each links to its product page):<\/p>\r\n\r\n\r\n\r\n\r\n
\"Britec<\/a><\/td>\r\n\"Britec<\/a><\/td>\r\n\"Britec<\/a><\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n

Need a Type 1 SPD for your project?<\/strong>\r\nSend Britec your system voltage, configuration and Iimp requirement, and our engineers will recommend the right Class\u202fI surge arrester and backup protector for your service entrance.\r\nRequest a Quote<\/a><\/span><\/p>\r\n\r\n

Domande frequenti<\/h2>\r\n
\r\n

Q: Where should a Type 1 SPD be installed in an electrical system?<\/strong><\/p>\r\n

A: At the origin of the installation \u2014 the main incoming supply or service entrance, ahead of the main disconnect \u2014 so it intercepts direct lightning current before downstream circuits.<\/p>\r\n\r\n<\/div>\r\n

\r\n

Q: Can a Type 1 SPD be used without a Type 2 SPD?<\/strong><\/p>\r\n

A: In a coordinated design the Type\u202f1 handles the bulk lightning current and a Type\u202f2 handles induced and switched surges at sub-panels. Using Type\u202f1 alone leaves smaller induced surges less protected, so cascade them for full coverage.<\/p>\r\n\r\n<\/div>\r\n

\r\n

Q: What Iimp rating do I need for a Type 1 SPD?<\/strong><\/p>\r\n

A: It depends on the lightning exposure from your risk assessment: 12.5\u202fkA, 25\u202fkA or 50\u202fkA per pole. Buildings with an LPS and exposed incoming lines typically need 25\u202fkA or 50\u202fkA.<\/p>\r\n\r\n<\/div>\r\n

\r\n

Q: Is a Type 1 SPD required if the building has no lightning rod?<\/strong><\/p>\r\n

A: A direct strike can still inject current via the power lines even without an LPS. Standards such as IEC\u202f62305 and IEC\u202f61643-11 assess the risk, and many service entrances still specify Type\u202f1 or Type\u202f1+2 for robust protection.<\/p>\r\n\r\n<\/div>\r\n

\r\n

Q: What is the difference between a Type 1 and a Type 1+2 SPD?<\/strong><\/p>\r\n

A: A Type\u202f1+2 combines Class\u202fI (Iimp) and Class\u202fII (In) protection in one module, useful where both direct-strike current and induced surges must be handled at the entrance. See the Type\u202f1+2 lightning surge arrester category<\/a> for examples.<\/p>\r\n\r\n<\/div>\r\n

\r\n

Q: How do I coordinate a Type 1 SPD with downstream protection?<\/strong><\/p>\r\n

A: Use energy coordination: Type\u202f1 at the entrance, Type\u202f2 at distribution and Type\u202f3 at equipment, plus a dedicated backup protector (SCB) upstream. This prevents a faulted stage from overloading the next.<\/p>\r\n\r\n<\/div>\r\n

Conclusione<\/h2>\r\n

UN electric SPD Type 1<\/strong> is the foundation of surge protection for any electrical system exposed to direct lightning current. Specified at the service entrance, rated by Iimp, and coordinated with Type\u202f2 and Type\u202f3 stages, it protects buildings, factories, hospitals and critical infrastructure from the most energetic transients. Britec Electric backs every Type\u202f1 SPD with two decades of manufacturing experience and Intertek SEMKO, T\u00dcV and CE certifications.<\/p>\r\n

Talk to a Britec SPD engineer<\/strong>\r\nGet a tailored Type\u202f1 SPD recommendation and a quotation for your panels, distribution boards or turnkey project.\r\nContattaci<\/a><\/span><\/p>\r\n\r\n

Related Resources<\/h2>\r\n

\u25cf Lightning Arrester vs Type 1 Surge Protection Device<\/a><\/p>\r\n

\u25cf Surge Protection Coordination: How To Cascade Type 1, 2, And 3 SPDs<\/a><\/p>\r\n

\u25cf How SPD Surge Protective Devices Are Designed For Modern Electrical Systems<\/a><\/p>","protected":false},"featured_media":2472,"parent":0,"menu_order":11,"template":"","meta":{"_acf_changed":false},"blog_category":[9],"class_list":["post-2672","blog","type-blog","status-publish","has-post-thumbnail","hentry","blog_category-industry-news"],"acf":{"des":"Practical guide to Electric SPD Type 1 (Class I) applications in electrical systems: where to install Type 1 surge arresters, how to choose the Iimp rating, and which Britec models protect service entrances.","txt":"

What Is an Electric SPD Type 1?<\/h2>\r\n

An electric SPD Type 1<\/strong> \u2014 also called a Class I surge protective device<\/strong> \u2014 is installed at the origin of an electrical installation, typically the main incoming supply, to discharge the partial lightning current (Iimp) that can enter a building through power lines when an external lightning protection system (LPS) is present. Rated by their Iimp withstand per pole (commonly 12.5\u202fkA, 25\u202fkA or 50\u202fkA per IEC\u202f61643-11), Type\u202f1 devices are built for the high-energy impulses a direct or nearby lightning strike can inject into the grid.<\/p>\r\n

For B2B buyers, panel builders and electrical engineers, a Type\u202f1 SPD is the first line of defence at the service entrance. It protects the whole installation and the downstream Type\u202f2 and Type\u202f3 devices that handle smaller, induced surges.<\/p>\r\n\r\n

Type 1 vs Type 2 vs Type 3 SPD \u2014 Where Each Belongs<\/h2>\r\n

Surge protective devices are classified by the surge they must withstand. The table below shows how a Type\u202f1 SPD<\/strong> differs from Type\u202f2 and Type\u202f3 in tested impulse and installation point.<\/p>\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n
Type<\/th>\r\nTested Impulse<\/th>\r\nTypical Installation Point<\/th>\r\n<\/tr>\r\n
Type 1 (Class I)<\/strong><\/td>\r\nIimp \u2014 direct lightning current (10\/350\u202f\u03bcs)<\/td>\r\nMain incoming supply \/ service entrance<\/td>\r\n<\/tr>\r\n
Type 2 (Class II)<\/strong><\/td>\r\nIn \u2014 induced \/ switched surges (8\/20\u202f\u03bcs)<\/td>\r\nDistribution boards \/ sub-panels<\/td>\r\n<\/tr>\r\n
Type 3 (Class III)<\/strong><\/td>\r\nCombination wave \u2014 fine protection<\/td>\r\nClose to sensitive equipment \/ sockets<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n

Electric SPD Type 1 Applications In Electrical Systems<\/h2>\r\n

Because a Type\u202f1 SPD<\/strong> is designed to take a direct lightning current, it is specified wherever the incoming supply can carry that energy. The most common Type\u202f1 SPD applications in electrical systems<\/strong> include:<\/p>\r\n

\u25cf Main distribution boards and service entrances<\/strong> \u2014 the primary point where the utility supply enters a building.<\/p>\r\n

\u25cf Buildings with an external lightning protection system (LPS)<\/strong> \u2014 where air terminals and down-conductors can inject lightning current into the power lines.<\/p>\r\n

\u25cf Industrial plants and factories<\/strong> \u2014 process lines, motor control centres and large connected loads exposed to switching and lightning overvoltage.<\/p>\r\n

\u25cf Commercial buildings, hospitals and data centres<\/strong> \u2014 sites where a single surge can halt critical operations and damage expensive electronics.<\/p>\r\n

\u25cf PV and renewable-energy inverters<\/strong> \u2014 exposed structures where DC and AC sides both need coordinated protection.<\/p>\r\n

\u25cf Railway, telecom and utility infrastructure<\/strong> \u2014 long exposed conductors that act as lightning collectors.<\/p>\r\n

\u25cf Critical electrical loads<\/strong> \u2014 any installation where downtime from a surge is unacceptable (see SPD protection for critical electrical loads<\/a>).<\/p>\r\n\r\n

Where to Install a Type 1 SPD in the Distribution Chain<\/h2>\r\n

A Type\u202f1 SPD<\/strong> is mounted at the origin of the installation, ahead of the main breaker, so it intercepts the lightning current before it reaches downstream circuits. It is almost always used as the first stage of a coordinated cascade: Type\u202f1 at the entrance, Type\u202f2 at distribution boards, and Type\u202f3 at the equipment. Proper coordination keeps each stage from overloading the next \u2014 Britec covers this in the Type\u202f1 lightning surge protection device category<\/a> and in our cascade guides.<\/p>\r\n

A dedicated backup protector (surge protective device coordinator, or SCB) is recommended on the upstream side of a Type\u202f1 SPD. It isolates a faulted SPD without tripping the main supply \u2014 Britec offers Class\u202fI dedicated backup protectors such as the BRSCB-I series for this role.<\/p>\r\n\r\n

How to Select a Type 1 SPD for Your Project<\/h2>\r\n

When specifying a Type\u202f1 SPD<\/strong>, match the device to the system and the expected exposure:<\/p>\r\n

\u25cf Iimp rating<\/strong> \u2014 12.5\u202fkA, 25\u202fkA or 50\u202fkA per pole, chosen from the risk assessment of direct-strike exposure.<\/p>\r\n

\u25cf Voltage protection level (Up)<\/strong> \u2014 keep it at or below the impulse withstand of the protected equipment.<\/p>\r\n

\u25cf System configuration<\/strong> \u2014 TNS, TNC-S or TT, and the required pole count (1P+N, 3P, 4P).<\/p>\r\n

\u25cf Status indication and remote signalling<\/strong> \u2014 for preventive maintenance in unmanned sites.<\/p>\r\n

\u25cf Standards and certification<\/strong> \u2014 compliant with IEC\u202f61643-11 \/ EN\u202f61643-11 and backed by third-party marks.<\/p>\r\n\r\n

Why Specify Britec Electric Type 1 SPDs<\/h2>\r\n

Britec Electric Wenzhou Co., Ltd. has manufactured surge protective devices since 2003 and supplies panel builders, distributors and EPC contractors worldwide. Our Type\u202f1 SPDs<\/strong> are certified by Intertek SEMKO, T\u00dcV and CE, and are engineered for the high Iimp demands of service-entrance protection. Three representative models are shown below.<\/p>\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n
Model<\/th>\r\nIimp per pole<\/th>\r\nConfiguration<\/th>\r\n<\/tr>\r\n
BR-25M 4P Type 1 25kA Surge Arrester<\/td>\r\n25\u202fkA<\/td>\r\n4P, TNS<\/td>\r\n<\/tr>\r\n
BR-50GR 4P Type 1 50kA Surge Arrester<\/td>\r\n50\u202fkA<\/td>\r\n4P, TNS<\/td>\r\n<\/tr>\r\n
BR-25VG 4P 25kA T1 Surge Protector<\/td>\r\n25\u202fkA<\/td>\r\n4P, TNS<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n

Product photos (white background, each links to its product page):<\/p>\r\n\r\n\r\n\r\n\r\n
\"Britec<\/a><\/td>\r\n\"Britec<\/a><\/td>\r\n\"Britec<\/a><\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n

Need a Type 1 SPD for your project?<\/strong>\r\nSend Britec your system voltage, configuration and Iimp requirement, and our engineers will recommend the right Class\u202fI surge arrester and backup protector for your service entrance.\r\nRequest a Quote<\/a><\/span><\/p>\r\n\r\n

Frequently Asked Questions<\/h2>\r\n
\r\n

Q: Where should a Type 1 SPD be installed in an electrical system?<\/strong><\/p>\r\n

A: At the origin of the installation \u2014 the main incoming supply or service entrance, ahead of the main disconnect \u2014 so it intercepts direct lightning current before downstream circuits.<\/p>\r\n\r\n<\/div>\r\n

\r\n

Q: Can a Type 1 SPD be used without a Type 2 SPD?<\/strong><\/p>\r\n

A: In a coordinated design the Type\u202f1 handles the bulk lightning current and a Type\u202f2 handles induced and switched surges at sub-panels. Using Type\u202f1 alone leaves smaller induced surges less protected, so cascade them for full coverage.<\/p>\r\n\r\n<\/div>\r\n

\r\n

Q: What Iimp rating do I need for a Type 1 SPD?<\/strong><\/p>\r\n

A: It depends on the lightning exposure from your risk assessment: 12.5\u202fkA, 25\u202fkA or 50\u202fkA per pole. Buildings with an LPS and exposed incoming lines typically need 25\u202fkA or 50\u202fkA.<\/p>\r\n\r\n<\/div>\r\n

\r\n

Q: Is a Type 1 SPD required if the building has no lightning rod?<\/strong><\/p>\r\n

A: A direct strike can still inject current via the power lines even without an LPS. Standards such as IEC\u202f62305 and IEC\u202f61643-11 assess the risk, and many service entrances still specify Type\u202f1 or Type\u202f1+2 for robust protection.<\/p>\r\n\r\n<\/div>\r\n

\r\n

Q: What is the difference between a Type 1 and a Type 1+2 SPD?<\/strong><\/p>\r\n

A: A Type\u202f1+2 combines Class\u202fI (Iimp) and Class\u202fII (In) protection in one module, useful where both direct-strike current and induced surges must be handled at the entrance. See the Type\u202f1+2 lightning surge arrester category<\/a> for examples.<\/p>\r\n\r\n<\/div>\r\n

\r\n

Q: How do I coordinate a Type 1 SPD with downstream protection?<\/strong><\/p>\r\n

A: Use energy coordination: Type\u202f1 at the entrance, Type\u202f2 at distribution and Type\u202f3 at equipment, plus a dedicated backup protector (SCB) upstream. This prevents a faulted stage from overloading the next.<\/p>\r\n\r\n<\/div>\r\n

Conclusion<\/h2>\r\n

An electric SPD Type 1<\/strong> is the foundation of surge protection for any electrical system exposed to direct lightning current. Specified at the service entrance, rated by Iimp, and coordinated with Type\u202f2 and Type\u202f3 stages, it protects buildings, factories, hospitals and critical infrastructure from the most energetic transients. Britec Electric backs every Type\u202f1 SPD with two decades of manufacturing experience and Intertek SEMKO, T\u00dcV and CE certifications.<\/p>\r\n

Talk to a Britec SPD engineer<\/strong>\r\nGet a tailored Type\u202f1 SPD recommendation and a quotation for your panels, distribution boards or turnkey project.\r\nContact Us<\/a><\/span><\/p>\r\n\r\n

Related Resources<\/h2>\r\n

\u25cf Lightning Arrester vs Type 1 Surge Protection Device<\/a><\/p>\r\n

\u25cf Surge Protection Coordination: How To Cascade Type 1, 2, And 3 SPDs<\/a><\/p>\r\n

\u25cf How SPD Surge Protective Devices Are Designed For Modern Electrical Systems<\/a><\/p>"},"_links":{"self":[{"href":"https:\/\/www.britecelectric.com\/it\/wp-json\/wp\/v2\/blog\/2672","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.britecelectric.com\/it\/wp-json\/wp\/v2\/blog"}],"about":[{"href":"https:\/\/www.britecelectric.com\/it\/wp-json\/wp\/v2\/types\/blog"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.britecelectric.com\/it\/wp-json\/wp\/v2\/media\/2472"}],"wp:attachment":[{"href":"https:\/\/www.britecelectric.com\/it\/wp-json\/wp\/v2\/media?parent=2672"}],"wp:term":[{"taxonomy":"blog_category","embeddable":true,"href":"https:\/\/www.britecelectric.com\/it\/wp-json\/wp\/v2\/blog_category?post=2672"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}