ان electric SPD Type 1 — also called a Class I surge protective device — 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 kA, 25 kA or 50 kA per IEC 61643-11), Type 1 devices are built for the high-energy impulses a direct or nearby lightning strike can inject into the grid.
For B2B buyers, panel builders and electrical engineers, a Type 1 SPD is the first line of defence at the service entrance. It protects the whole installation and the downstream Type 2 and Type 3 devices that handle smaller, induced surges.
Surge protective devices are classified by the surge they must withstand. The table below shows how a Type 1 SPD differs from Type 2 and Type 3 in tested impulse and installation point.
| يكتب | Tested Impulse | Typical Installation Point |
|---|---|---|
| Type 1 (Class I) | Iimp — direct lightning current (10/350 μs) | Main incoming supply / service entrance |
| Type 2 (Class II) | In — induced / switched surges (8/20 μs) | Distribution boards / sub-panels |
| Type 3 (Class III) | Combination wave — fine protection | Close to sensitive equipment / sockets |
Because a Type 1 SPD is designed to take a direct lightning current, it is specified wherever the incoming supply can carry that energy. The most common Type 1 SPD applications in electrical systems include:
● Main distribution boards and service entrances — the primary point where the utility supply enters a building.
● Buildings with an external lightning protection system (LPS) — where air terminals and down-conductors can inject lightning current into the power lines.
● Industrial plants and factories — process lines, motor control centres and large connected loads exposed to switching and lightning overvoltage.
● Commercial buildings, hospitals and data centres — sites where a single surge can halt critical operations and damage expensive electronics.
● PV and renewable-energy inverters — exposed structures where DC and AC sides both need coordinated protection.
● Railway, telecom and utility infrastructure — long exposed conductors that act as lightning collectors.
● Critical electrical loads — any installation where downtime from a surge is unacceptable (see SPD protection for critical electrical loads).
A Type 1 SPD 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 1 at the entrance, Type 2 at distribution boards, and Type 3 at the equipment. Proper coordination keeps each stage from overloading the next — Britec covers this in the Type 1 lightning surge protection device category and in our cascade guides.
A dedicated backup protector (surge protective device coordinator, or SCB) is recommended on the upstream side of a Type 1 SPD. It isolates a faulted SPD without tripping the main supply — Britec offers Class I dedicated backup protectors such as the BRSCB-I series for this role.
When specifying a Type 1 SPD, match the device to the system and the expected exposure:
● Iimp rating — 12.5 kA, 25 kA or 50 kA per pole, chosen from the risk assessment of direct-strike exposure.
● مستوى حماية الجهد (أعلى) — keep it at or below the impulse withstand of the protected equipment.
● System configuration — TNS, TNC-S or TT, and the required pole count (1P+N, 3P, 4P).
● Status indication and remote signalling — for preventive maintenance in unmanned sites.
● Standards and certification — compliant with IEC 61643-11 / EN 61643-11 and backed by third-party marks.
Britec Electric Wenzhou Co., Ltd. has manufactured surge protective devices since 2003 and supplies panel builders, distributors and EPC contractors worldwide. Our Type 1 SPDs are certified by Intertek SEMKO, TÜV and CE, and are engineered for the high Iimp demands of service-entrance protection. Three representative models are shown below.
| Model | Iimp per pole | إعدادات |
|---|---|---|
| BR-25M 4P Type 1 25kA Surge Arrester | 25 kA | 4P, TNS |
| BR-50GR 4P Type 1 50kA Surge Arrester | 50 kA | 4P, TNS |
| BR-25VG 4P 25kA T1 واقي التيار | 25 kA | 4P, TNS |
Product photos (white background, each links to its product page):
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Q: Where should a Type 1 SPD be installed in an electrical system?
A: At the origin of the installation — the main incoming supply or service entrance, ahead of the main disconnect — so it intercepts direct lightning current before downstream circuits.
Q: Can a Type 1 SPD be used without a Type 2 SPD?
A: In a coordinated design the Type 1 handles the bulk lightning current and a Type 2 handles induced and switched surges at sub-panels. Using Type 1 alone leaves smaller induced surges less protected, so cascade them for full coverage.
Q: What Iimp rating do I need for a Type 1 SPD?
A: It depends on the lightning exposure from your risk assessment: 12.5 kA, 25 kA or 50 kA per pole. Buildings with an LPS and exposed incoming lines typically need 25 kA or 50 kA.
Q: Is a Type 1 SPD required if the building has no lightning rod?
A: A direct strike can still inject current via the power lines even without an LPS. Standards such as IEC 62305 and IEC 61643-11 assess the risk, and many service entrances still specify Type 1 or Type 1+2 for robust protection.
Q: What is the difference between a Type 1 and a Type 1+2 SPD?
A: A Type 1+2 combines Class I (Iimp) and Class II (In) protection in one module, useful where both direct-strike current and induced surges must be handled at the entrance. See the Type 1+2 lightning surge arrester category for examples.
Q: How do I coordinate a Type 1 SPD with downstream protection?
A: Use energy coordination: Type 1 at the entrance, Type 2 at distribution and Type 3 at equipment, plus a dedicated backup protector (SCB) upstream. This prevents a faulted stage from overloading the next.
ان electric SPD Type 1 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 2 and Type 3 stages, it protects buildings, factories, hospitals and critical infrastructure from the most energetic transients. Britec Electric backs every Type 1 SPD with two decades of manufacturing experience and Intertek SEMKO, TÜV and CE certifications.
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اتصل بنا
● Lightning Arrester vs Type 1 Surge Protection Device
● Surge Protection Coordination: How To Cascade Type 1, 2, And 3 SPDs
● How SPD Surge Protective Devices Are Designed For Modern Electrical Systems
