When comparing Type 1 vs Type 2 SPD for solar applications, Type 1, Type 2 and Type 1+2 SPDs should not be treated as three quality levels of the same product.

They are intended for different surge conditions.

In many photovoltaic installations, a Тип 2 DC SPD is used where the main risk comes from induced lightning surges and switching overvoltages.

Где partial lightning current may enter the PV electrical system, however, Type 1 capability should be evaluated. A Type 1+2 SPD can provide both lightning-current and Type 2 surge-protection functions at the same installation point.

For projects in Spain, the decision should therefore be based on:

• External lightning protection
• Possibility of partial lightning current entering DC cables
• Место установки
• PV maximum open-circuit voltage
• Длина кабеля
• Equipment impulse withstand level
• Earthing and equipotential bonding
• Applicable Spanish and IEC requirements

Quick Answer: Type 1 vs Type 2 vs Type 1+2

The important point is:

Do not select an SPD simply because Type 1+2 sounds “better” than Type 2. Select it according to the surge environment at the installation point.

IEC 61643-31 covers SPDs specifically intended for the DC side of photovoltaic installations rated up to 1500 В пост. тока. IEC 61643-32 covers selection, installation and coordination of SPDs in PV systems up to 1500 В пост. тока, and also considers the AC side up to 1,000 V RMS at 50/60 Hz.

If you are still determining the basic voltage, application and protection requirements, first read our guide on how to choose a DC SPD for solar installations in Spain.

What Is the Difference Between Type 1, Type 2 and Type 1+2 DC SPDs?

The most useful way to understand Type 1 vs Type 2 SPD for solar applications is to compare the surge conditions they are designed for and the electrical ratings that need to be checked.

Type 1 is not simply a Type 2 SPD with a larger current rating

One of the most common purchasing mistakes is to compare only the number of kiloamps printed on the front of the device.

Например:

• Type 1 performance is closely associated with Iimp
• Type 2 performance commonly uses In and Imax
• Both still require verification of Up and Ucpv

Поэтому:

40 kA Imax does not automatically mean that a Type 2 SPD can replace a Type 1 SPD.

Iimp and Imax describe different surge-performance characteristics.

When Is a Type 2 DC SPD Normally Used?

A Type 2 DC SPD is commonly evaluated when the expected surge threat is mainly caused by:

• Indirect lightning effects
• Electromagnetic induction
• Nearby lightning
• Switching operations
• Transient overvoltage generated elsewhere in the system

Typical PV applications include:

This is why the correct statement is:

Type 2 is commonly used where the lightning protection design does not require Type 1 lightning-current capability.

It would be technically unsafe to say:

“Every residential rooftop solar system only needs a Type 2 SPD.”

Two rooftop systems can have very different lightning-protection arrangements.

When Should a Type 1 DC SPD Be Evaluated?

Type 1 should be evaluated when there is a realistic possibility that partial lightning current can enter the PV electrical system.

This can occur under several design conditions.

1. External Lightning Protection Is Installed

A building equipped with an external lightning protection system requires the PV array, mounting frame, DC conductors, earthing system and equipotential bonding to be considered as part of the overall lightning-protection design.

However:

External lightning protection does not automatically mean that every PV SPD must be Type 1.

The complete arrangement needs to be examined.

2. Required Separation Cannot Be Maintained

The physical relationship between:

• Lightning conductors
• PV frames
• фотоэлектрические модули
• DC cables
• Metallic structures

can influence whether lightning current is transferred into the PV installation.

This is one reason that the question:

“Does the building have a lightning rod?”

is not sufficient on its own.

A better question is:

“Can the required separation between the external LPS and PV installation be maintained?”

3. Partial Lightning Current May Reach the DC Circuit

This is one of the most important differences between Type 1 and Type 2 selection.

Where a surge-protection design expects partial lightning current at an SPD location, Iimp becomes a critical specification.

Selecting a high-Imax Type 2 device without checking Iimp does not solve that requirement.

4. The Engineering Specification Requires Type 1

Some EPC drawings and tender documents specify Type 1 directly.

In this case, purchasing should verify more than the words “Type 1.”

Check:

When Is a Type 1+2 SPD a Better Choice?

A Type 1+2 SPD should be considered when the same protection point requires both lightning-current capability and Type 2 surge protection.

Possible situations include:

• Entry point exposed to partial lightning current
• Inverter entrance requiring combined protection
• Project documents specifying Type 1+2
• Space-constrained distribution equipment
• A coordinated protection concept using a combined SPD

But Type 1+2 should not be treated as an automatic upgrade.

A Type 1+2 product still has to be evaluated according to:

Iimp + In + Imax + Up + Ucpv + Iscpv

For example, manufacturers offer Type 1+2 products with very different lightning-current capacities. Phoenix Contact’s current Type 1+2 portfolio includes devices with different discharge capabilities rather than treating every Type 1+2 product as electrically identical.

The label alone therefore does not provide enough information.

Does Every Solar Installation in Spain Need a Type 1 SPD?

Нет.

This is one of the most important points in this article.

There is no technically sound rule that says:

“Every photovoltaic installation in Spain requires a Type 1 SPD.”

Spain’s Reglamento Electrotécnico para Baja Tensión (REBT) includes ITC-BT-23 concerning protection against transient overvoltages in low-voltage installations. However, ITC-BT-23 should not be interpreted as a simple rule directly assigning Type 1 to every PV DC circuit.

PV DC surge protection must instead be evaluated together with:

• PV-specific SPD requirements
• Lightning protection design
• Installation topology
• External LPS
• Earthing
• Защита оборудования
• Project documentation

Standards and References Relevant to the Decision

IEC 61643-31 explicitly applies to SPDs connected to the DC side of PV generators and inverter DC inputs up to 1,500 V DC.

IEC 61643-32 specifically addresses PV systems located both on buildings and in ground-mounted/free-field installations, which is important because the lightning and earthing environment can differ significantly between these applications.

Why the Project Location in Spain Still Matters

Another mistake is to treat “Spain” as one identical lightning environment.

AEMET maintains national lightning-detection and lightning-climatology information covering Spain and publishes spatial maps, tables and statistical analysis of lightning activity.

Its climatology shows why lightning exposure should be treated geographically rather than assuming the same conditions everywhere in Spain.

AEMET’s operational lightning network also detects lightning across mainland Spain, the Balearic Islands and the Canary Islands.

This means project information such as:

• Madrid
• Barcelona
• Valencia
• Zaragoza
• Málaga
• Mallorca
• Canary Islands

should not be replaced by the simple statement:

“The project is in Spain.”

Project location is one input to the risk assessment, not a direct rule that independently determines the SPD type.

How External Lightning Protection Changes SPD Selection

An external lightning protection system and an SPD perform different jobs.

An external LPS is intended to manage lightning effects on the structure.

An SPD is used within the electrical protection concept to:

• Divert surge current
• Limit transient voltage
• Protect connected electrical equipment

An SPD does не replace:

• Air terminals
• Down conductors
• Earthing
• Equipotential bonding
• Correct cable routing

Likewise, an external lightning system does not eliminate the need to evaluate surge protection for electrical circuits.

The two systems need to be coordinated.

Where Should Type 1, Type 2 and Type 1+2 SPDs Be Installed?

The following table is intentionally labelled “to evaluate.”

It should not be treated as a mandatory configuration for every PV project.

A photovoltaic combiner box is often an important protection point

Outdoor DC conductors may converge at the photovoltaic combiner box, making it a logical location to evaluate surge protection.

But the SPD type depends on the design.

Do not automatically specify Type 2 simply because the SPD is installed in a combiner box.

Long DC Cables: Why One SPD May Not Be Enough

The SPD closest to the PV array and the SPD closest to the inverter do not necessarily protect exactly the same point.

A long conductor can be exposed to additional induced voltage.

IEC 61643-32 specifically covers the selection, location and coordination of SPDs throughout a PV installation rather than treating an entire PV plant as one protection point.

For projects with long DC runs, evaluate:

Do not use an arbitrary cable-length number without checking the applicable engineering standard and project configuration.

The Most Important DC SPD Ratings to Compare

The SPD type alone cannot determine whether a product is suitable.

Technical Parameter Comparison

Ucpv: Do Not Select an SPD from “1000V System” Alone

This is one of the most commercially important checks.

IEC 61643-31 applies to PV DC SPDs up to 1500 В пост. тока, but that does not mean any 1,500 V-labelled SPD is suitable for every system.

The designer should determine the maximum PV array open-circuit voltage under the project’s lowest expected temperature.

PV module Voc generally rises as cell temperature falls.

Therefore the correct workflow is:

Module Voc → number of modules in series → temperature correction → maximum array Voc → select suitable Ucpv

Not:

“Inverter says 1000V → buy any 1000V SPD.”

This subject deserves a separate article, which is why the next guide in this series will cover:

1000V vs 1500V DC SPD for Solar PV Systems.

Iimp vs In vs Imax: Why the Numbers Cannot Be Compared Directly

One of the most important points in a Type 1 vs Type 2 SPD for solar comparison is understanding the difference between Iimp, In and Imax.

A product advertising:

Imax = 40 kA

does not automatically satisfy a project specification requiring:

Type 1 + defined Iimp

because they represent different test and protection concepts.

Manufacturer technical data provides a useful real-world demonstration of this distinction: current lightning/surge products specify separate 10/350 μs and 8/20 μs discharge capabilities rather than presenting them as one interchangeable current rating.

Up: The Rating That Is Often Ignored

Large current figures are easy to market.

However, the purpose of the SPD is ultimately to prevent damaging voltage from reaching protected equipment.

That makes Up — voltage protection level — a critical selection parameter.

The engineer should compare:

SPD Up

with:

the impulse withstand capability of the protected inverter or other equipment.

A device with an impressive current rating but an unsuitable Up may not provide the desired equipment protection.

Iscpv and Backup Protection

Photovoltaic DC circuits have different fault behaviour from conventional AC systems.

The SPD and its disconnection arrangement must therefore be suitable for the available PV short-circuit current.

Check:

• SPD Iscpv
• Manufacturer’s recommended backup protection
• Ток фотоэлектрического стринга
• Parallel strings
• gPV fuse arrangement
• Connection topology

The SPD should be coordinated with the system’s Защита предохранителями gPV, rather than selecting the fuse and SPD as unrelated components.

Type 1 vs Type 2 vs Type 1+2: Practical Project Scenarios

The following are engineering scenarios, not claimed customer case studies.

They are included to show the decision process without inventing project results.

Это различие важно.

We are не saying:

“Ground-mounted PV always requires Type 1.”

We are saying:

Its exposure, earthing and lightning-protection arrangement make a more detailed engineering assessment necessary.

Several mistakes repeatedly appear when engineers and buyers compare Type 1 vs Type 2 SPD for solar projects, especially when selection is based only on SPD type or discharge-current ratings.

Common Type 1 vs Type 2 SPD Selection Mistakes

Can an AC Type 2 SPD Be Used on the PV DC Side?

Normally, a conventional AC SPD should not be substituted for a PV-specific DC SPD simply because the voltage printed on the device appears similar.

IEC 61643-31 specifically covers SPDs designed for the DC side of PV generators and inverter DC inputs up to 1500 В пост. тока.

The buyer should therefore check:

• PV DC application
• Ucpv
• Iscpv
• PV connection diagram
• Applicable PV SPD standard

rather than only checking the voltage value.

Practical SPD Selection Checklist for a Spanish Solar Project

Before requesting a quotation or approving an SPD, collect the following information.

A technically useful RFQ is therefore:

“1500V DC PV project, inverter input protection, external LPS installed, Type 1+2 required, please confirm Ucpv, Iimp, In, Imax, Up, Iscpv, connection configuration and IEC 61643-31 test documentation.”

This gives a manufacturer far more useful information than:

“Please quote 1500V SPD.”

Final Decision Table

If you only remember one table from this article, use this one.

Заключение

The difference between Type 1 vs Type 2 SPD for solar cannot be reduced to one product being stronger or better than another.

For most projects, the correct logic is:

Тип 2
→ commonly evaluated for induced lightning and switching overvoltages.

Тип 1
→ evaluated when partial lightning current may enter the PV electrical installation.

Тип 1+2
→ evaluated where both functions are required at the same installation point.

For a solar PV project in Spain, the final decision should consider:

• Lightning protection concept
• External LPS
• Separation conditions
• Project location
• Maximum corrected PV Voc
• Ucpv
• Iimp
• На сайте
• Imax
• Вверх
• Iscpv
• Длина кабеля
• SPD coordination
• Applicable Spanish and IEC requirements

Most importantly:

Do not specify Type 1+2 simply because it appears to offer the highest level of protection. Specify the SPD that matches the actual lightning and surge conditions of the project.

IEC 61643-31 provides the PV-specific product framework for DC-side SPDs up to 1,500 V DC, while IEC 61643-32 addresses their selection, location and coordination within PV systems.

For product selection, you can view KUANGYA Type 2 and Type 1+2 DC SPDs, or send us:

• Напряжения системы
• Maximum PV Voc
• Installation drawing
• Lightning protection information
• SPD installation location
• Required ratings
• Количество

for product-selection support.

Часто задаваемые вопросы

1. Is a Type 2 SPD enough for a residential solar installation?

Type 2 is commonly evaluated for residential PV installations where the protection requirement is primarily against induced lightning and switching surges.

However, the external lightning protection system, cable arrangement, separation conditions and project requirements must also be checked.

Therefore, Type 2 should not automatically be assumed suitable for every residential installation.

2. Does a building with a lightning rod always require a Type 1 DC SPD?

Нет.

The presence of an external lightning protection system is an important design factor, but it does not by itself prove that every DC SPD must be Type 1.

The engineer should also evaluate separation, bonding, cable routing and whether partial lightning current can enter the PV circuit.

3. Is Type 1+2 better than Type 2?

Not automatically.

Type 1+2 provides combined lightning-current and surge-protection functions.

If the project only requires Type 2 performance at a particular installation point, selecting Type 1+2 solely because it appears “stronger” does not necessarily improve the overall protection design.

4. Can a Type 1+2 SPD replace separate Type 1 and Type 2 SPDs?

At some installation points, a properly selected Type 1+2 device can provide both functions.

However, this does not mean one Type 1+2 SPD can automatically replace all coordinated SPDs throughout a PV system.

Long cable routes and multiple protection zones may still require additional devices.

5. What is the difference between Iimp and Imax?

Iimp is associated with lightning impulse-current capability and is particularly important when evaluating Type 1 protection.

Imax is associated with the maximum discharge-current capability used for Type 2 performance.

The two values should not be treated as interchangeable.

A high Imax does not automatically provide the Iimp performance required for Type 1 applications.

6. Can an AC Type 2 SPD be used on the DC side of a solar installation?

A conventional AC SPD should not be selected for PV DC use simply because its voltage rating appears suitable.

PV DC SPDs should be designed and tested for the electrical characteristics of photovoltaic DC circuits.

IEC 61643-31 specifically covers SPDs for the DC side of PV systems up to 1,500 V DC.

7. Where should the SPD be installed if the DC cable is long?

Long cable routes may require coordinated SPDs at more than one location, such as near the array or combiner box and near the inverter.

The actual arrangement depends on cable length, installation layout, external lightning protection and equipment requirements.

IEC 61643-32 specifically addresses SPD location and coordination in photovoltaic installations.

8. Which standard applies to PV DC SPDs in Spain?

UNE-EN 61643-31 / IEC 61643-31 is an important product reference for PV DC surge protective devices.

IEC 61643-32 provides principles for selection, installation and coordination.

Spanish electrical regulations, lightning-protection requirements and individual project specifications must also be considered before final selection.

9. Does every solar installation in Spain require Type 1 SPD?

Нет.

SPD type should be determined from the lightning protection concept, installation arrangement and applicable project requirements.

“Spain = Type 1” is not a technically correct selection rule.

10. What information should I send a supplier before requesting a DC SPD quotation?

At minimum, provide:

• Project location
• Maximum PV voltage
• Maximum array Voc
• Installation position
• External lightning protection information
• Required SPD type
• Iimp / In / Imax if specified
• Required Up
• Количество столбов
• Количество
• Required certificates and test documents

This allows the supplier to check the actual technical requirement rather than quoting only according to voltage.