Type 1 vs Type 2 vs Type 3 SPD: The Definitive Whitepaper for Global Surge Protection

Introduzione

In the modern electrical landscape, where infrastructure is increasingly interconnected and sensitive, the Dispositivo di protezione dalle sovratensioni (SPD) has evolved from a luxury to a non-negotiable necessity.

For industrial facilities, commercial complexes, and critical data centers, the choice between DOCUP di tipo 1, tipo 2 e tipo 3 can determine whether a system remains resilient or suffers catastrophic failure.

A single lightning strike or severe grid transient can cause millions in equipment damage and operational downtime.

For professional distributors and procurement managers, understanding SPD types is not only about technical compliance but also about risk management and long-term profitability.

A Elettricità LEEYEE, we have specialized in low-voltage protection devices since 2009. Operating from our 8,000 m² manufacturing facility with 8 production lines, we supply high-performance SPDs to European, American, and Australian markets.

This whitepaper explains the technical principles, waveform physics, and sourcing considerations for professional buyers.

---

Part I: The Technical Foundation – Defining SPD Types

Surge Protective Devices are categorized based on their installation location and the type of surge they are designed to handle.

This classification follows international standards:

• IEC 61643-11

• EN 61643-11

Type 1 SPD: Lightning Arrester (Class I)

Type 1 SPDs are designed to handle direct lightning strike currents.

Posizione

• Installed at the service entrance or main distribution board

Forma d'onda di prova

• 10/350µs impulse current (Iimp)

Funzione

• Diverts massive lightning energy from lightning rods or overhead lines safely to ground.

LEEYEE Advantage

• High-capacity Spark Gap or heavy-duty MOV technology

• Iimp capability up to 25kA or 50kA per pole

---

Type 2 SPD: Main Protection (Class II)

I DOCUP di tipo 2 proteggono da indirect lightning strikes and switching transients.

Posizione

• Installato in main distribution boards or sub-distribution boards

Forma d'onda di prova

• 8/20µs nominal discharge current (In)

Funzione

• Clamps residual voltage from upstream SPDs

• Protects against switching surges from motors, transformers, or grid disturbances

LEEYEE Advantage

• Esempio: LY2-C Series

• Optimized Voltage Protection Level (Up < 1.5kV)

---

Type 3 SPD: Point-of-Use Protection (Class III)

I DOCUP di tipo 3 forniscono fine protection for sensitive electronics.

Posizione

• Installed close to equipment (within 5–10 meters)

Forma d'onda di prova

• Combination Wave

  • 1.2/50µs voltage

  • 8/20µs current

Funzione

• Protects sensitive devices such as:

  • PLC controllers

  • Servers

  • Medical equipment

LEEYEE Advantage

• Compact designs

• Can be integrated into power sockets or small enclosures

---

Part II: The Physics of Waveforms – 10/350µs vs 8/20µs

The key technical difference between DOCUP di tipo 1 e 2 lies in the test waveform.

10/350µs Waveform (Direct Lightning)

This waveform simulates a direct lightning strike.

Characteristics:

• 10µs rise time

• 350µs decay time

Energy Characteristics:

• Contains about 20× more energy than an 8/20µs waveform of the same peak current.

Engineering Challenge:

• Only true Type 1 SPDs can survive this energy without catastrophic failure.

---

8/20µs Waveform (Indirect Surge)

This waveform represents indirect lightning effects or switching surges.

Characteristics:

• 8µs rise time

• 20µs decay time

Energy Characteristics:

• Lower energy than 10/350µs

• Occurs much more frequently

Engineering Challenge:

• SPDs must withstand thousands of repetitive surge events.

---

Part III: Comparison Table

---

Part IV: Coordination & Cascading – The 10 Meter Rule

A common mistake is installing only a Type 1 SPD and assuming the entire building is protected.

Surge protection must be layered.

Why Coordination Matters

If Type 1 and Type 2 SPDs are installed too close together:

• Type 2 SPD may trigger first

• It will attempt to absorb high-energy lightning current

• This can destroy the device instantly

---

Coordination Distance

Recommended rule:

• Maintain at least 10 meters of cable distance between Type 1 and Type 2 SPD.

Reason:

• Cable inductance creates impedance

• Ensures Type 1 SPD activates first

---

Type 1+2 Combined SPD

In compact installations where 10 meters is not possible:

LEEYEE provides Type 1+2 combined SPDs

Vantaggi:

• Internal coordination

• Compact modular design

• Handles both direct and indirect surges

---

Part V: B2B Sourcing Advantage – The LEEYEE Difference

For professional buyers, supplier reliability is critical.

Risk Mitigation

LEEYEE provides:

Authentic Certification

• TUV

• CB

• CE

• SAA

All certificates are verifiable.

PICC Global Insurance

All products are insured by People’s Insurance Company of China (PICC).

Benefits:

• Financial protection

• Liability coverage for distributors

Supply Chain Transparency

We support:

• Factory audits

• Production inspection reports

• Testing videos

---

Production Capacity

Manufacturing strength:

• 8,000 m² factory

• 8 production lines

• Stable delivery capability

Quality assurance:

• Professional surge testing equipment

• Strict batch inspection procedures

---

Part VI: Procurement Guide – 5 Red Flags When Buying SPDs

Professional buyers should watch for the following risks.

1. Fake Type 1 Claims

If a supplier claims DOCUP di tipo 1 but only provides 8/20µs data, it is not a real Type 1 device.

Always demand 10/350µs (Iimp) test data.

---

2. No Thermal Protection

Low-quality SPDs may lack disconnettori termici.

Risk:

• MOV overheating

• Potential fire hazard

---

3. High Voltage Protection Level

Se Up > 2.5kV for a 230V system, protection may be insufficient.

Recommended:

Up < 1.5kV

---

4. Fake Certificates

Always verify:

• Certificate number

• Certification body database

Avoid suppliers providing only logos without documentation.

---

5. No Product Liability Insurance

Without insurance, distributors bear all risk of product failure.

LEEYEE provides PICC product liability coverage.

---

Domande frequenti (FAQ)

Do I need a Type 1 SPD if I don’t have a lightning rod?

Usually no.

If there is no external lightning protection and no overhead lines, Type 2 SPD at the main board is typically sufficient.

However, for critical infrastructure, Type 1+2 combined SPDs are recommended.

---

What is the difference between Iimp and Imax?

Iimp

• Used for DOCUP di tipo 1

• 10/350µs waveform

• Simulates direct lightning

Imax

• Used for DOCUP di tipo 2

• 8/20µs waveform

• Simulates indirect surges

---

Can I use only a Type 1 SPD?

No.

Type 1 SPDs handle energy, but residual voltage may remain high.

A Type 2 SPD downstream is required to clamp voltage further.

---

Con quale frequenza devono essere sostituiti i DOCUP?

Most SPDs include indicatori di stato.

• Green: normal

• Red: replace

Inspection is recommended:

• Annually

• After major lightning events

LEEYEE SPDs allow modular replacement without rewiring.

---

What is a 3+1 SPD configuration?

In a 4-pole SPD:

• Three MOVs protect L1, L2, L3 to Neutral

• One Tubo di scarico del gas (GDT) protegge Neutral to Earth

This configuration is recommended for TT and TN-S systems.

---

Does LEEYEE support OEM / ODM?

Sì.

Offriamo free customization services, including:

• Logo printing

• Product color

• Packaging design

Helping distributors build their own private brand.

---

Conclusione

Choosing the correct SPD type is a small investment that prevents catastrophic electrical failure.

By partnering with Elettricità LEEYEE, distributors gain access to:

• Advanced surge protection technology

• Authentic international certifications

• Reliable manufacturing capacity

Contact us today to discuss wholesale cooperation and private label opportunities.

---