IEC 61643 Explained: A Complete Guide to Surge Protective Devices

Last Updated: July 2026

TL;DR: What IEC 61643 Means for SPD Selection

IEC 61643 is one of the most important international standard families for Surge Protective Devices, also known as SPDs.

For engineers, EPC contractors, solar installers, EV charging station manufacturers, telecom cabinet designers, and industrial electrical teams, IEC 61643 helps answer one key question:

How should surge protective devices be tested, selected, installed, and coordinated for low-voltage electrical systems?

In simple terms:

IEC 61643 defines requirements and test methods for SPDs.
SPDs are designed to limit transient overvoltages and divert surge currents.
IEC 61643 applies to different SPD applications, including AC power systems, DC power circuits, photovoltaic systems, and signal or communication lines.
A correct SPD selection should consider voltage, surge current rating, protection level, installation location, earthing system, and coordination with upstream or downstream devices.
IEC 61643 should not be treated as only a certificate name. It should be used as part of real protection design.

For modern electrical infrastructure, IEC 61643 is especially important in:

PV-Solaranlagen
EV-Ladestationen
Batteriespeichersysteme
Datenzentren
Telekommunikationsschränke
Industrielle Schalttafeln
Commercial and low-voltage distribution systems

A properly selected SPD can help reduce lightning surge damage, switching transient damage, control board failure, inverter failure, charger downtime, and communication equipment failure.

Navigation

What Is IEC 61643?
Why Surge Protective Devices Are Needed
How an SPD Works
Main Parts of the IEC 61643 Standard Family
IEC 61643-01: General Requirements for SPDs
IEC 61643-11: SPDs for AC Low-Voltage Power Systems
IEC 61643-31 and IEC 61643-32: SPDs for Photovoltaic Systems
IEC 61643-41: SPDs for DC Power Circuits
IEC 61643-21 and IEC 61643-22: SPDs for Signal and Communication Lines
Key SPD Parameters Engineers Must Understand
Type 1, Type 2, and Type 3 SPDs
How to Select an SPD for Real Projects
Common SPD Selection Mistakes
Application Examples
FAQ

1. What Is IEC 61643?

IEC 61643 is a family of international standards for low-voltage surge protective devices.

A Surge Protective Device, or SPD, is used to protect electrical and electronic equipment against transient overvoltages. These transient overvoltages may come from lightning activity, grid switching, transformer switching, inductive loads, fault events, or other electrical disturbances.

IEC 61643-01 contains common requirements for SPDs and applies to surge protective devices connected to circuits or equipment rated up to 1,000 V AC RMS or 1,500 V DC. It also specifies performance and safety requirements, tests, and ratings for SPDs.

This is why IEC 61643 is highly relevant to modern electrical protection projects. Many electrical systems today include sensitive components such as:

Wechselrichter
Power modules
PLC controllers
Communication boards
Data acquisition devices
Batteriemanagementsysteme
EV charger controllers
Telecom equipment
Industrielle Automatisierungssysteme

These devices are more sensitive to transient voltage than traditional electrical loads. A short surge event may not destroy a cable, but it can damage a control board, communication module, inverter, charger module, sensor, or monitoring device.

IEC 61643 helps engineers and project teams evaluate SPDs in a more standardized way.

It does not mean every project uses the same SPD. Instead, it helps define how SPDs should be classified, tested, and selected according to the system and risk level.

2. Why Surge Protective Devices Are Needed

Electrical systems are exposed to transient overvoltages in many situations.

The most common sources include:

Surge Source	Typische Ursache	Possible Result
Blitzschlag	Direct or nearby lightning strikes	Equipment breakdown, insulation stress, control board failure
Grid switching	Utility switching, capacitor bank switching	Transient overvoltage entering distribution system
Transformer switching	Energization or de-energization	Voltage spikes and electromagnetic disturbance
Motor loads	Large inductive loads switching on or off	Transient voltage in local electrical network
Lange Kabelwege	Outdoor cabling, rooftop PV arrays, remote cabinets	Induced surge voltage
Poor grounding	High impedance grounding path	Increased overvoltage stress
Internal faults	Electrical fault or insulation failure	Secondary transient disturbance

A surge may last only microseconds, but the energy can be high enough to damage electronics.

In solar PV systems, surges can enter through PV strings, inverter AC terminals, communication lines, or grounding paths.

In EV charging stations, surges can enter through utility input, charger cabinets, long cable routes, communication networks, or outdoor installations.

In telecom cabinets, surges can enter through power lines, antenna systems, signal cables, or grounding systems.

In data centers, even a short transient can affect UPS systems, distribution panels, monitoring systems, and network equipment.

That is why IEC 61643 is not only a standard for component manufacturers. It is also a practical reference for system designers.

3. How an SPD Works

An SPD is designed to limit transient overvoltage and divert surge current away from protected equipment.

In normal operation, the SPD remains in a high-impedance state. It does not carry significant current.

When a transient overvoltage occurs, the SPD changes state and provides a lower-impedance path. This allows surge current to be diverted toward the grounding system or protective path, reducing the voltage stress on downstream equipment.

After the surge event, a properly functioning SPD returns to its normal state.

IEC descriptions of several SPD standards emphasize that SPDs contain at least one nonlinear component and are intended to limit surge voltages and divert surge currents. For example, IEC 61643-31 applies this principle to SPDs for photovoltaic installations, while IEC 61643-41 applies it to SPDs for DC power circuits.

Common SPD technologies include:

Metal Oxide Varistor, or MOV
Gas Discharge Tube, or GDT
Spark gap technology
Hybrid protection circuits

Each technology has different characteristics. In real applications, SPD design may combine different components to balance response time, discharge capacity, leakage current, and protection level.

An SPD should not be treated like a normal switch or circuit breaker. It does not interrupt load current in the same way as a breaker. It does not replace fuse protection. It does not solve overload problems.

Its job is specific:

Limit transient voltage and divert surge current.

For a deeper technical explanation, this Funktionsprinzip von DC-Überspannungsschutzgeräten (SPD) guide explains how a DC surge protective device detects a voltage surge and diverts excess energy away from sensitive equipment.

For complete electrical protection, SPD should work together with:

Fuse protection
Stromkreisunterbrecher
Proper grounding
Equipotential bonding
Verlegung der Kabel
Insulation coordination
Thermal management
Maintenance inspection

How a surge protective device diverts transient overvoltage to ground — An SPD limits transient overvoltage by diverting surge current away from protected electrical equipment.

4. Main Parts of the IEC 61643 Standard Family

IEC 61643 is not only one document. It is a standard family covering different SPD applications.

Important parts include:

IEC Standard	Hauptanwendung	Warum es wichtig ist
IEC 61643-01	General SPD requirements	Common requirements for SPDs
IEC 61643-11	AC low-voltage power system SPDs	Commonly used for AC power distribution
IEC 61643-12	Selection and application principles for AC SPDs	Helps with SPD location and coordination
IEC 61643-21	Telecom and signalling network SPDs	Important for signal and communication lines
IEC 61643-22	Selection and application of telecom and signalling SPDs	Helps protect communication systems
IEC 61643-31	SPDs for photovoltaic installations	Important for PV DC-side surge protection
IEC 61643-32	Selection and coordination of PV SPDs	Important for PV system design
IEC 61643-41	SPDs for DC power circuits	Important for DC electrical systems up to 1,500 V DC

IEC 61643 standard family for AC DC PV and signal line surge protective devices — The IEC 61643 standard family covers surge protective devices for AC systems, DC circuits, PV installations, and communication lines.

Not every project needs every part of IEC 61643.

Zum Beispiel:

A commercial AC distribution panel mainly needs AC SPD requirements.
A solar PV system needs PV DC-side SPD requirements.
A telecom cabinet may need both power SPD and signal line SPD.
A data center may need AC power SPD and communication line SPD.
An EV charging station may need AC SPD, DC SPD, and signal line protection depending on the design.

The key is to match the correct IEC 61643 part to the real electrical system.

5. IEC 61643-01: General Requirements for SPDs

IEC 61643-01:2024 is important because it provides common requirements for SPDs.

According to the IEC official description, IEC 61643-01:2024 applies to devices for surge protection against indirect and direct effects of lightning or other transient overvoltages. It applies to SPDs intended to be connected to circuits or equipment rated up to 1,000 V AC RMS or 1,500 V DC, and it specifies performance and safety requirements, tests, and ratings.

For engineers and procurement teams, this means IEC 61643-01 should be understood as a base document.

It helps create a common framework for SPD evaluation, including:

Product performance
Safety requirements
Ratings
Test methods
Application voltage range
Common SPD terminology

This is important because different industries use different SPD applications.

A PV DC SPD, an AC distribution SPD, a data line SPD, and a DC power circuit SPD may not be the same product, but they all belong to the broader surge protection logic.

When a supplier says an SPD complies with IEC 61643, engineers should ask:

Which part of IEC 61643?
Is it for AC power, DC power, PV, or signal line protection?
What is the rated voltage?
What is the discharge current?
What is the voltage protection level?
What test report or certificate supports the claim?
Does the SPD match the actual system voltage and earthing arrangement?

A professional SPD selection process should not stop at the words “IEC 61643 compliant.”

It should verify the correct part, rating, and application.

6. IEC 61643-11: SPDs for AC Low-Voltage Power Systems

IEC 61643-11 is one of the most commonly referenced standards for AC surge protective devices used in low-voltage AC power systems.

The IEC official page states that IEC 61643-11:2025 applies to devices for surge protection against indirect and direct effects of lightning or other transient overvoltages.

The earlier IEC 61643-11:2011 version applied to SPDs packaged to be connected to 50/60 Hz AC power circuits and equipment rated up to 1,000 V RMS. It also stated that such devices contain at least one nonlinear component and are intended to limit surge voltages and divert surge currents.

For practical engineering, IEC 61643-11 is relevant to:

Low-voltage AC distribution panels
Kommerzielle Gebäude
Industrielle Steuerschränke
Data center power systems
Telecom AC input cabinets
EV charger AC input circuits
Solar inverter AC output panels
UPS distribution systems

AC SPDs are often installed at:

Hauptverteilerschränke
Unterverteilerschränke
Equipment input cabinets
Outdoor electrical cabinets
Bedienfelder
Power supply panels

AC SPD Selection Factors

When selecting an AC SPD, engineers should check:

Parameter	Warum es wichtig ist
Nominal voltage	Must match system voltage
Maximale Dauerspannung	Must tolerate normal voltage conditions
SPD type	Type 1, Type 2, or Type 3 according to installation and risk
Nennableitstoßstrom	Shows repeated surge handling ability
Maximaler Ableitstoßstrom	Shows high surge capacity
Voltage protection level	Lower value means better downstream protection, if properly selected
Erdungssystem	TN, TT, IT systems require different protection design
Short-circuit current rating	Must match installation conditions
Backup protection	Fuse or breaker coordination may be required
Fernmeldekontakt	Useful for monitoring in critical systems
Visual indicator	Helps maintenance teams identify end-of-life status

AC surge protective device installed in low voltage electrical cabinet under IEC 61643-11 — AC surge protective devices are commonly used in low-voltage distribution panels, industrial cabinets, EV chargers, and data center power systems.

For commercial distribution panels, industrial facilities, EV charger input cabinets, and data center power systems, an AC surge protective device is commonly used to reduce grid-side overvoltage and switching surge damage.

AC SPDs are especially important in outdoor cabinets, EV charging stations, industrial equipment, and energy infrastructure because these systems often face grid disturbance and environmental exposure.

7. IEC 61643-31 and IEC 61643-32: SPDs for Photovoltaic Systems

Solar PV systems require special attention because PV arrays are usually installed outdoors and connected through long DC cable runs.

IEC 61643-31 applies to surge protective devices connected to the DC side of photovoltaic installations rated up to 1,500 V DC. These devices are designed for connection to the DC side of photovoltaic installations rated up to 1,500 V DC.

IEC 61643-32:2017 describes principles for selection, installation, and coordination of SPDs used in PV systems up to 1,500 V DC and for the AC side of PV systems rated up to 1,000 V RMS.

This is very important for solar PV protection.

A PV system may experience surges from:

Nearby lightning
Long PV string cables
Metal mounting structures
Exposition auf dem Dach
Ground potential rise
Inverter connection points
AC distribution side
Communication monitoring lines

PV surge protection should usually consider both DC and AC sides:

PV System Area	Protection Consideration
PV string side	DC SPD near combiner box or inverter input
Mähdrescherkasten	DC SPD, fuse, isolation
Wechselrichter DC-Eingang	DC SPD coordination
Wechselrichter AC-Ausgang	AC SPD
Monitoring system	Signal line surge protection where needed
Grounding system	Proper bonding and low impedance path

In many PV projects, a PV-Kombinationskasten integrates DC SPD, gPV fuse protection, grounding, and DC isolation before the inverter.

Why PV DC SPD Is Different

PV DC surge protective device inside solar combiner box for IEC 61643-31 protection — PV DC SPDs protect photovoltaic strings, combiner boxes, and inverter inputs from lightning-induced transient overvoltage.

A DC SPD for PV systems is not the same as a general AC SPD.

For PV arrays, combiner boxes, and energy storage DC circuits, a properly selected DC surge protective device helps reduce lightning-induced transient overvoltage risk.

PV systems may operate at high DC voltages such as 1,000 V DC or 1,500 V DC. DC circuits also have different arc behavior compared with AC circuits.

Because of this, engineers should use SPDs designed and tested for PV DC applications, not simply use an AC SPD in a DC PV circuit.

For KUANGYA’s target customers, this topic is especially important because solar PV systems, inverters, combiner boxes, BESS, and EV charging infrastructure often share similar protection logic.

A strong PV SPD article can support many internal links across the website.

8. IEC 61643-41: SPDs for DC Power Circuits

DC power circuit surge protective device for EV charging BESS and solar PV systems — IEC 61643-41 is important for DC power circuits used in EV charging, BESS, PV systems, and industrial DC cabinets.

As DC systems become more common, DC surge protection is becoming more important.

IEC 61643-41 applies to surge protective devices connected to DC power circuits and equipment rated up to 1,500 V DC. These devices are intended to be connected to DC power circuits and equipment rated up to 1,500 V DC. The standard specifies performance and safety requirements, tests, and ratings.

This is highly relevant to modern applications such as:

DC fast charging equipment
Batteriespeichersysteme
DC-Verteilerschränke
PV-related DC systems
Industrial DC power supply systems
Telecom DC power systems
Power conversion equipment

DC power systems are becoming more common because many modern energy systems are based on DC conversion and storage.

Zum Beispiel:

Solar PV arrays generate DC power.
Batteries store DC power.
EV fast chargers use DC output.
Telecom systems often use DC power architecture.
Industrial control systems may include DC auxiliary circuits.

For these systems, surge protection design must consider:

Systemspannung
Maximale Dauerspannung
DC fault behavior
Grounding arrangement
Leitungslänge
Installation environment
Coordination with upstream and downstream protection devices
Suitable DC SPD standards and test requirements

DC SPD selection is especially important because using the wrong SPD can create safety and reliability problems.

A DC circuit should be protected with products designed for DC applications.

9. IEC 61643-21 and IEC 61643-22: SPDs for Signal and Communication Lines

Modern electrical systems are not only power circuits.

They also include:

Ethernet communication
RS485 communication
Sensor lines
Fire alarm signals
Monitoring cables
Data acquisition systems
Remote control lines
Telecom networks
Building management systems
OCPP communication for EV chargers

IEC 61643-21 applies to surge protective devices connected to telecommunications and signalling networks, including networks that may also provide power on the same line such as PoE. The IEC description states that these devices are intended to be connected to telecommunications and signalling networks and equipment rated up to 1,000 V RMS and 1,500 V DC. It also notes that these networks can provide power on the same line, such as Power over Ethernet.

IEC 61643-22:2015 describes principles for selection, operation, location, and coordination of SPDs connected to telecommunication and signalling networks with nominal system voltages up to 1,000 V RMS AC and 1,500 V DC. It also covers multiservice SPDs that include protection for signalling lines and power lines in the same enclosure.

This matters because a surge can damage a system through the communication side even when the power side is protected.

Zum Beispiel:

A telecom cabinet may have AC or DC power protection, but an unprotected signal cable can still introduce surge energy.
A data center may protect the UPS input, but network equipment can still be exposed through communication lines.
An EV charger may have power SPD, but network or payment modules may fail after a surge event.
A PV inverter may have DC and AC SPD, but monitoring communication may still be vulnerable.

Therefore, complete surge protection should review both power lines and signal lines.

10. Key SPD Parameters Engineers Must Understand

SPD selection requires more than choosing a voltage and price.

Engineers should understand the following parameters.

Maximale kontinuierliche Betriebsspannung

Maximum continuous operating voltage is the voltage the SPD can continuously withstand without operating incorrectly.

If the value is too low, the SPD may age quickly or fail under normal operating conditions.

If the value is too high, the voltage protection level may not be suitable for sensitive equipment.

Spannung Schutzniveau

Voltage protection level indicates the residual voltage that remains during surge discharge under test conditions.

A lower protection level can help protect downstream equipment, but it must be selected together with the system voltage, SPD type, and installation conditions.

Long cable length and poor installation may increase the actual voltage seen by protected equipment.

Nenn-Entladestrom

Nominal discharge current represents the surge current level the SPD can handle under specified test conditions.

It is important for repeated surge exposure.

Maximaler Entladestrom

Maximum discharge current indicates a higher surge current capability.

This parameter is often highlighted in product marketing, but engineers should not select an SPD only by the biggest number. The correct value depends on site risk, installation level, and coordination.

Impulse Current

Impulse current is especially relevant for Type 1 SPDs, which are used where lightning current may be expected.

This is important in installations with external lightning protection systems or high lightning exposure.

SPD-Typ

SPD type indicates where and how the SPD is usually applied.

Common classifications include:

Typ 1 SPD
Typ 2 SPD
Typ 3 SPD

Each type has different test conditions and application purposes.

Short-Circuit Current Rating

The SPD must be suitable for the available short-circuit current at the installation point.

If the short-circuit capability is not suitable, failure conditions may become unsafe.

Backup-Schutz

Some SPD installations require upstream fuse or circuit breaker protection.

The backup protection must be coordinated with the SPD according to manufacturer requirements.

Visual Indicator

A visual indicator helps maintenance teams identify whether an SPD module is still functional or has reached end of life.

Remote Signal Contact

A remote signal contact is useful in critical systems such as:

Datenzentren
Telecom sites
EV charging networks
PV power plants
BESS cabinets
Industrielle Automatisierungssysteme

It allows the SPD status to be monitored remotely.

Type 1 Type 2 and Type 3 SPD coordination in electrical distribution system — Coordinated SPD protection reduces surge energy from the main entrance to equipment-level protection.

11. Type 1, Type 2, and Type 3 SPDs

SPD type is one of the most important concepts in IEC 61643-related discussions.

Typ 1 SPD

Type 1 SPDs are designed to handle high-energy lightning current components.

They are usually installed near the service entrance or main distribution board where lightning current may enter the electrical system.

Typical use cases:

Buildings with external lightning protection systems
Hauptverteilerschränke
High lightning exposure sites
Industrial facilities
Large energy infrastructure projects

Type 1 SPD is not automatically required for every installation. It depends on lightning risk, building design, local electrical rules, and project requirements.

Typ 2 SPD

Type 2 SPDs are widely used in low-voltage distribution systems to protect against switching surges and induced lightning surges.

They are often installed in:

Verteilertafeln
Solar inverter cabinets
Kombinierkästen
EV charger cabinets
Industrielle Steuerschränke
Telecom power cabinets
Commercial electrical systems

For many solar PV and industrial applications, Type 2 SPD is the most commonly used protection level.

Typ 3 SPD

Type 3 SPDs are usually installed close to sensitive equipment.

They provide local protection, often after upstream Type 1 or Type 2 protection.

Typical use cases:

Empfindliche Elektronik
Control equipment
Communication equipment
Office equipment
Local equipment-level protection

Type 3 SPDs should not be used as the only protection layer in high-risk installations.

SPD Coordination

Type 1, Type 2, and Type 3 SPDs may be used together in a coordinated protection system.

The goal is to reduce surge energy step by step:

Main entrance protection → Distribution protection → Equipment-level protection

This layered design is important in large facilities such as data centers, factories, telecom sites, and EV charging stations.

12. How to Select an SPD for Real Projects

A practical SPD selection process should follow a structured method.

Step 1: Identify the System Type

First, confirm the system type:

AC low-voltage distribution
DC power circuit
Solar PV DC circuit
EV charging station
Telecom signal network
Data center power system
Industrial control cabinet
BESS DC cabinet

Different systems may need different IEC 61643 references.

Step 2: Confirm System Voltage

Check:

Nominal voltage
Maximum operating voltage
AC or DC system
System grounding
Spannungsschwankungen
PV open-circuit voltage where applicable

Incorrect voltage selection is one of the most common SPD mistakes.

Step 3: Check Installation Location

SPD location affects its type and rating.

Typical locations include:

Main distribution board
Unterverteilerschrank
Equipment input cabinet
PV-Kombinationskasten
Wechselrichter DC-Eingang
Wechselrichter AC-Ausgang
EV charger cabinet
Telecom power cabinet
Signal line entrance

Step 4: Evaluate Lightning and Surge Risk

Bedenken Sie:

Local lightning density
Outdoor installation
Leitungslänge
Building height
Rooftop PV installation
Nearby metal structures
Existing lightning protection system
Grid quality
Criticality of the equipment

High-risk sites may need stronger SPD coordination.

Step 5: Confirm SPD Type

Choose Type 1, Type 2, or Type 3 according to installation point and risk level.

Zum Beispiel:

Main entrance with lightning risk: Type 1 or Type 1+2 may be considered.
Distribution cabinet: Type 2 is commonly used.
Sensitive equipment side: Type 3 may be used as supplementary protection.

Step 6: Check Discharge Current Rating

Select the discharge current rating according to risk level and application.

Do not choose only based on the largest advertised current.

A balanced design should consider:

Project risk
Standard requirement
Equipment sensitivity
Installation level
Wartungskosten
Produktzuverlässigkeit

Step 7: Check Voltage Protection Level

The voltage protection level should be suitable for downstream equipment.

Sensitive electronics may require lower residual voltage, but installation cable length and coordination must also be considered.

Step 8: Confirm Backup Protection

Check whether the SPD requires backup fuse or breaker protection.

The backup protection must follow product datasheet requirements.

Step 9: Plan Maintenance

SPD is not a “set and forget” device.

Maintenance teams should check:

Visual indicator
Remote alarm
Module replacement condition
Tightness of terminals
Grounding condition
Signs of overheating
Surge event history where monitoring is available

For critical systems, remote signal contacts are recommended.

13. Common SPD Selection Mistakes

Mistake 1: Using AC SPD in DC Applications

This is a serious mistake.

AC SPDs and DC SPDs are not always interchangeable. DC circuits have different characteristics, and DC-rated SPDs should be used for DC systems.

For PV systems, use SPDs intended for photovoltaic DC applications.

For DC power circuits, use SPDs designed for DC power applications.

Mistake 2: Selecting Only by Maximum Discharge Current

A large maximum discharge current number does not automatically mean better protection.

Engineers should also check:

Voltage protection level
Nennableitstoßstrom
Systemspannung
SPD type
Short-circuit rating
Backup protection
Zertifizierung
Installation position

Mistake 3: Ignoring Grounding

SPD performance depends heavily on grounding and bonding.

Poor grounding can reduce protection effectiveness.

A good SPD needs a suitable discharge path.

Mistake 4: Long Connection Cables

Long SPD connection leads can increase residual voltage at the protected equipment.

Short, straight, and properly routed connections are important for surge protection performance.

Mistake 5: No Coordination Between SPDs

If multiple SPDs are used, they should be coordinated.

Poor coordination may cause the wrong device to operate, reduce protection effectiveness, or increase maintenance problems.

Mistake 6: No Maintenance Plan

SPD modules may age after repeated surge events.

A visual indicator or remote signal contact helps maintenance teams identify failed modules.

Without inspection, a failed SPD may remain unnoticed until the next surge damages equipment.

Mistake 7: Treating SPD as a Fuse or Breaker

An SPD is not a fuse.

An SPD is not a circuit breaker.

Engineers comparing protection functions can read this DC Fuse vs DC SPD guide to understand why fuses protect against overcurrent while SPDs protect against transient overvoltage.

An SPD limits transient overvoltage and diverts surge current. It does not replace overcurrent protection.

Complete electrical protection should include SPD, fuse, circuit breaker, grounding, cable protection, and thermal safety where needed.

14. Application Examples

14.1 Solar Inverter Protection

Solar inverters are exposed to both DC-side and AC-side surges.

For a complete application example, read this Schutz von Solarwechselrichtern guide covering DC SPD, AC SPD, PV fuse coordination, arc faults, and cabinet safety.

A typical protection strategy may include:

DC SPD at PV string or combiner box side
DC SPD near inverter input
AC SPD at inverter output
Proper grounding and bonding
Fuse protection for PV strings
Monitoring for critical systems

For EV infrastructure projects, this EV charging station electrical protection guide explains how SPD, fuse protection, grounding, cabinet fire safety, and maintenance work together.

Eine vollständige DC photovoltaic protection design should coordinate DC SPD, gPV fuse protection, DC circuit breakers, disconnectors, and grounding inside PV combiner boxes or inverter input circuits.

PV systems should refer to IEC 61643-31 for PV SPD requirements and IEC 61643-32 for selection, installation, and coordination principles.

14.2 EV Charging Station Protection

EV charging stations include AC input, power modules, DC output circuits, communication systems, and outdoor cabinets.

A typical protection strategy may include:

AC SPD at charger input
DC SPD where required by design
Signal line SPD for communication systems where needed
Fuse protection for DC circuits
Proper grounding
Cabinet fire safety
Maintenance inspection

IEC 61643 helps engineers evaluate SPD selection for both AC and DC parts of the charging system.

14.3 BESS Protection

Battery Energy Storage Systems contain high-value DC equipment, power conversion systems, control boards, battery management systems, and communication modules.

A typical protection strategy may include:

DC SPD for battery-side or DC distribution circuits
AC SPD for PCS output or grid connection
Signal line SPD for monitoring systems
Fuse protection for DC fault isolation
Cabinet fire suppression
Thermische Überwachung

For BESS projects, SPD selection should be part of a broader electrical and fire safety strategy.

Battery storage projects should also review battery energy storage fire protection because surge events, overcurrent faults, thermal conditions, and cabinet safety must be evaluated together.

14.4 Telecom Cabinet Protection

Telecom cabinets may include AC input, DC power supply, batteries, communication equipment, signal lines, and outdoor enclosures.

A typical protection strategy may include:

AC or DC SPD for power input
Signal line SPD
Proper grounding and bonding
Cabinet fire safety
Temperature and humidity control
Remote SPD status monitoring

IEC 61643-21 and IEC 61643-22 are especially relevant when protecting telecommunication and signalling networks.

14.5 Data Center Protection

Data centers require high availability.

Surge events can affect:

USV-Anlagen
Switchgear
Power distribution units
Überwachungssysteme
Kommunikationsnetze
Server support equipment

A data center surge protection strategy may include:

Type 1 or Type 2 SPD at main distribution level
Type 2 SPD at downstream panels
Type 3 SPD near sensitive equipment where needed
Signal line protection
Fernüberwachung
Maintenance inspection

For lightning electromagnetic impulse protection inside structures, IEC 62305-4:2024 provides requirements for surge protection measures for electrical and electronic systems to reduce the risk of permanent failures due to lightning electromagnetic impulse.

15. IEC 61643 and IEC 62305: What Is the Difference?

IEC 61643 and IEC 62305 are related, but they are not the same.

IEC 61643 focuses on surge protective devices.

IEC 62305 focuses on lightning protection of structures and the related risk management and protection measures.

IEC 62305-1:2024 provides general principles for protection of structures against lightning, including their installations, contents, and persons.

IEC 62305-4 provides requirements for surge protection measures for electrical and electronic systems inside structures, helping reduce the risk of permanent failures caused by lightning electromagnetic impulse.

In practical projects:

IEC 62305 helps evaluate lightning protection and structure-level risk.
IEC 61643 helps evaluate SPD product requirements, selection, and application.

For large projects, both may be considered.

Zum Beispiel:

A building with external lightning protection may need Type 1 SPD at the main entrance.
A solar PV system on a rooftop may need PV DC SPD and AC SPD.
A data center may need coordinated SPD protection across different distribution levels.
An EV charging site may need site-level and cabinet-level SPD protection depending on exposure.

16. Recommended KUANGYA SPD Selection Logic

For customers selecting KUANGYA surge protective devices, the first step should be application matching.

For Solar PV Systems

For PV projects, this Solar PV protection strategy explains how SPD systems, DC fuse coordination, and fire suppression work as a layered protection chain.