最終更新日：2026年7月17日 | バージョン 1.1

要約：実務エンジニアリングにおけるIEC 62548

IEC 62548は、太陽光発電アレイ設計における主要な国際規格です。.

現在の主要な発行版は以下の通りです。 IEC 62548-1:2023, 、および2025年に発行された修正案1です。.

実務エンジニアリングの観点から、IEC 62548は太陽光発電アレイ設計における以下の主要なトピックを扱っています。

• DCアレイ配線
• 最大システム電圧
• 並列ストリング設計
• 過電流保護
• 開閉および絶縁
• 接地規定
• 保護装置の協調

最も重要な原則は単純です：

PVアレイは、通常の動作値だけでなく、想定される最大電気的条件および環境条件を考慮して設計しなければなりません。.

技術者は、寒冷時の開放電圧、並列ストリングからの逆電流、DC開閉能力、ケーブルの状態、および保護協調を考慮する必要があります。.

したがって、IEC 62548は製品チェックリストとしてではなく、PVアレイ設計のフレームワークとして扱うべきである。.

本ガイドでは、この規格を実務的なエンジニアリングの観点から解説する。.

目次

1. IEC 62548とは何か
2. IEC 62548の現行バージョン
3. IEC 62548の適用範囲
4. PVアレイの最大電圧
5. PVストリングおよび並列アレイの設計
6. 過電流保護およびgPVヒューズ
7. PV直流ケーブルの設計
8. 開閉および直流遮断
9. 接地および等電位ボンディング
10. サージ保護およびIEC 61643
11. PV接続箱の設計
12. インバータの協調
13. 検査および文書化
14. IEC 62548における一般的な設計ミス
15. 実践的な設計ワークフロー
16. IEC 62548 エンジニアリングチェックリスト
17. よくある質問
18. 最終的なエンジニアリング推奨事項

1. IEC 62548とは何か？

IEC 62548 は、太陽光発電アレイの電気設計および安全性について議論する際によく用いられます。.

現在の出版物のタイトルは以下の通りです：

IEC 62548-1: 太陽光発電（PV）アレイ－第1部：設計要件

この規格は、PV直流システムの特定の特性によって生じる設計上のリスクに対処するものです。.

太陽光発電アレイは、以下の理由により従来の電気回路とは異なります。

• 十分な日光がある限り常に電圧を発生させる
• 低温時に高い開放電圧を発生させる
• 複数の並列ストリングを含む
• 屋外の長いDCケーブル経路を使用する
• DC 1000Vまたは1500Vで動作する
• AC遮断後も通電状態が維持される

これらの特性は、以下の選定に影響を与えます。

• ケーブル
• gPVヒューズ
• 直流スイッチ
• アイソレーター
• サージ保護装置
• コンバイナーボックス
• インバータ接続

IEC 62548は、これらの課題に対処するためのシステムレベルのフレームワークを提供します。.

その価値は、単に適合製品を特定することにとどまりません。.

この規格は、PVアレイ全体をどのように統合的に設計すべきかをエンジニアが理解する一助となります。 太陽光発電（PV）電気保護システム.

2. IEC 62548の現行バージョン

多くの古い技術記事では、依然として以下が参照されています。 IEC 62548:2016.

For current engineering work, the core publication is:

The current consolidated publication is IEC 62548-1:2023+AMD1:2025.

The general term IEC 62548 remains widely used in industry and online searches.

However, technical documentation should identify the actual edition used for a project.

This is especially important in:

• Tender specifications
• EPC technical documents
• 適合宣言
• 設計報告書
• 検査記録

技術者は、プロジェクトがIEC規格の国内または地域的な採用版を使用しているかどうかも確認する必要がある。.

以下のような一般的な記述は：

IEC 62548に基づき設計

関連する版数や採用規格を特定するよりも精度が低い可能性がある。.

3. IEC 62548の適用範囲は何か？

IEC 62548-1は、主に太陽光発電アレイの設計に焦点を当てています。.

その適用範囲には、以下のような主要な項目が含まれます。

• DCアレイ配線
• 電気的保護装置
• 開閉装置
• 接地規定

実用的なシステムという観点では、本規格は太陽光発電アレイから最終的な電力変換機器（通常はインバータ）に至るまでの経路を対象としています。.

太陽光発電プロジェクトにおけるすべてのサブシステムを網羅していると想定すべきではありません。.

例えば、蓄電池システムには以下のような個別の課題が存在します。

• バッテリー故障電流
• バッテリー管理
• DCバス保護
• 熱伝播

より広範な太陽光発電設備の要件についても調整が必要であり、 IEC 60364-7-712:2025 適用される各国の電気規則に従うこと。.

これは重要なエンジニアリングの原則につながります：

単一のIEC規格が、太陽光発電所全体のあらゆる保護要件を定義できると期待すべきではありません。.

IEC 62548は、主に太陽光発電アレイの設計レイヤーを対象としている。.

その他の規格では、特定の機器や設置機能に関するより詳細な要件が規定されている。.

4. 最大太陽光発電アレイ電圧

最大太陽光発電電圧は、最初に確立すべき設計パラメータの一つである。.

MPPT電圧のみに基づいて設計してはならない

インバータの通常のMPPT動作電圧は、太陽光発電アレイが生成し得る最大電圧とは異なる。.

最大設計電圧は、以下を含む要因に依存する：

• モジュールの開放電圧
• 直列モジュール数
• モジュール温度係数
• Minimum expected temperature

Cold weather is particularly important.

As module temperature decreases, open-circuit voltage generally increases.

A string that appears acceptable under standard test conditions may exceed a device voltage limit under cold operating conditions.

Check the Complete DC Circuit

The maximum voltage assessment affects:

• PVモジュール
• コネクタ
• DC cables
• gPVヒューズ
• ヒューズホルダー
• SPD
• 直流（DC）アイソレーター
• 配線用遮断器（MCB/MCCB）
• コンバイナーボックス
• インバーター入力

A system described as “1500V DC” is not automatically suitable for 1500V operation simply because the inverter or SPD carries a 1500V rating.

Every relevant component in the DC path must be suitable for the calculated conditions.

The complete electrical path must be reviewed, not only the main equipment.

5. PV Strings and Parallel Array Design

Series-connected modules primarily influence voltage.

Parallel-connected strings significantly affect current and fault conditions.

Normal String Current Is Not Enough

The engineer should review module data including:

• Maximum power current
• Short-circuit current
• 最大システム電圧
• Manufacturer protection limitations

However, normal operating current does not fully describe the fault condition.

Reverse Current from Parallel Strings

Consider one PV string operating independently.

Its available current is limited by the electrical characteristics of that string.

Now consider multiple strings connected in parallel.

If one string develops a fault, healthy strings may contribute reverse current toward the damaged circuit.

The designer should assess whether this current could exceed the safe limits of:

• PVモジュール
• ストリングケーブル
• コネクタ
• Other connected components

This analysis directly affects the need for string overcurrent protection.

More parallel strings do not simply mean that a larger fuse should be installed.

The fault architecture must be evaluated.

6. Overcurrent Protection and gPV Fuses

Overcurrent protection is one of the most important areas of PV array design.

What Is a gPV Fuse?

A gPV fuse is designed for photovoltaic DC circuit protection.

PV fuse-links for string and array protection are specifically addressed by IEC 60269-6.

PV circuits can involve:

• High DC voltage
• 連続動作電流
• 並列ストリングからの逆電流
• High enclosure temperatures
• Outdoor thermal cycling

These operating conditions differ from many conventional AC applications.

Understanding the difference between a gPV fuse and a standard fuse is important because ordinary AC fuses should not automatically be used as substitutes in PV DC circuits.

Does Every PV String Need a Fuse?

そうだ。.

The need for string protection depends on factors such as:

• 並列ストリング数
• 潜在的な逆流電流
• Module limitations
• ケーブルの許容電流
• Equipment withstand capability

The correct process is:

Analyze the fault condition first. Select the protective device second.

Key gPV Fuse Selection Parameters

A gPV fuse review should include:

Rated DC Voltage

The fuse and fuse holder must be suitable for the maximum relevant DC voltage.

定格電流

The fuse should carry normal PV operating current without nuisance operation while still protecting the circuit during abnormal overcurrent.

Module Limitations

The module manufacturer’s protection limits should be checked.

破断能力

The device must be capable of interrupting the applicable fault current.

Installation Temperature

Fuse behavior can be influenced by actual enclosure temperature.

A combiner box in direct sunlight may operate at a much higher internal temperature than the outdoor ambient temperature.

プロテクション・コーディネーション

A fuse should not be selected independently from the protected circuit.

The protection relationship can be simplified as:

PV Source → Cable → Equipment Limit → Protective Device

The protective device should operate before an unacceptable current condition causes serious damage to the protected circuit.

This is why fuse selection is an engineering coordination problem rather than a simple current-rating comparison.

For common 1000V PV string applications, engineers can also review KUANGYA’s 10×38 gPV fuse link for solar systems.

7. PV DC Cable Design

PV cable design is directly related to protection.

A fuse or breaker cannot correct fundamentally incorrect conductor selection.

Current-Carrying Capacity

Cable sizing should consider:

• Design current
• 周囲温度
• Cable grouping
• 設置方法
• エンクロージャー温度
• Solar exposure

The design should reflect realistic installation conditions.

定格電圧

Cable insulation must be suitable for the maximum PV circuit voltage.

This becomes increasingly important in 1500V DC systems.

Cable Routing

PV cable routing should consider:

• Mechanical protection
• Sharp edges
• UV exposure
• Water accumulation
• Connector strain
• メンテナンスアクセス

Positive and negative conductors should also be routed in a way that avoids unnecessarily large loop areas.

Cable management is not only an installation-quality issue.

It influences long-term electrical reliability.

Connector Compatibility

PV connectors are a common failure point.

Physically mating connectors should not automatically be assumed to be electrically compatible.

Differences in:

• Contact materials
• Contact geometry
• Mechanical tolerances

may increase contact resistance.

This can lead to:

• Local heating
• Insulation damage
• Arcing
• Long-term failure

Connector selection and installation should therefore form part of the PV electrical design review.

8. Switching and DC Isolation

Safe isolation is a major requirement in PV array design.

Purpose of a DC Isolator

A DC isolator provides a means of separating part of the PV DC circuit.

It may support:

• メンテナンス
• Inspection
• Inverter replacement
• Combiner box servicing
• Emergency procedures

The device must be suitable for the actual PV DC application.

A DC Isolator Is Not Automatically a Circuit Breaker

The two devices perform different functions.

A DC isolator primarily provides an isolation function.

An overcurrent protection device responds to abnormal current conditions.

A circuit breaker may provide switching and protective functions according to its design.

Engineers should select the device according to the required function rather than using the terms interchangeably.

Verify DC Switching Capability

PV DC switching is technically demanding because DC current does not have the natural periodic zero crossing found in AC systems.

The designer should verify:

• DC voltage rating
• 現在のレーティング
• Pole configuration
• Wiring arrangement
• Switching duty
• 環境適合性

Some multi-pole DC devices require a specific connection arrangement to achieve their intended rating.

Requirements for switches, disconnectors and switch-disconnectors are addressed by IEC 60947-3.

Incorrect wiring may reduce interruption capability.

Isolation Must Be Practical

A disconnect shown on a single-line diagram may still be poorly positioned in the actual installation.

Engineers should ask:

• Is the isolator safely accessible?
• Is the isolated circuit clearly identified?
• Can maintenance personnel control reconnection?
• Does the arrangement support real maintenance work?

These factors should be evaluated together during 直流（DC）スイッチ断路器の選定, rather than checking voltage and current labels independently.

Safe isolation is both an electrical and operational design issue.

9. Earthing and Bonding

PV arrays may include extensive conductive structures such as:

• Module frames
• Mounting rails
• Electrical enclosures
• Cable management systems

The earthing and bonding strategy should be coordinated with:

• Electrical installation design
• Inverter requirements
• Lightning protection
• Applicable local regulations

Where protective bonding is required, the continuity of the bonding path should be maintained throughout the life of the installation.

Potential long-term problems include:

• 接続の緩み
• 腐食
• Dissimilar metals
• Mechanical damage

Earthing Does Not Replace Surge Protection

A good earthing arrangement does not eliminate the need for correctly selected SPDs.

Similarly, an SPD does not correct a poor bonding system.

These functions interact but are not interchangeable.

10. Surge Protection and IEC 61643

PV arrays often include long outdoor conductors.

These conductors can be exposed to transient overvoltages caused by:

• Nearby lightning
• Direct lightning effects
• Electromagnetic coupling
• Switching events

IEC 62548 should be used together with more specific SPD standards where detailed surge protection design is required.

The IEC 61643 series includes:

• IEC 61643-31 for SPDs used on the DC side of PV installations
• IEC 61643-32 for PV SPD selection, installation and coordination

For a wider explanation of the standard family, SPD classifications and selection parameters, read our complete IEC 61643 surge protective device guide.

Key PV SPD Parameters

Important selection parameters may include:

• 最大連続使用電圧
• 電圧保護レベル
• 公称放電電流
• Maximum discharge capability
• SPD type
• PV system topology

Selecting a product simply because it is described as a “solar SPD” is not sufficient.

Installation Location Matters

SPD performance depends partly on installation.

Long connection conductors can add additional voltage during a fast transient event.

Connection paths should therefore be kept appropriately short and direct.

Long cable distances between the PV array, combiner equipment and inverter may also require protection at more than one location.

Surge protection should be evaluated across the complete electrical path.

For 600V to 1500V photovoltaic applications, KUANGYA provides a Type 2 PV surge protective device for combiner boxes, inverter DC inputs and PV distribution cabinets.

11. PV Combiner Box Design

について PVコンバイナーボックス is a major coordination point in multi-string systems.

It may include:

• gPVヒューズ
• ヒューズホルダー
• DC SPD
• DC switching devices
• バスバー
• ターミナル
• 監視装置

The combiner box should reflect the overall PV array protection strategy.

String Input Design

レビュー

• Number of incoming strings
• ストリング電流
• Reverse-current conditions
• Fuse requirements
• Cable entry
• Polarity identification

Output Circuit

The combined output may carry significantly more current than one individual string.

The designer should verify:

• Busbar rating
• Output cable rating
• Terminal rating
• Switching-device rating

Internal Temperature

Heat can be produced by:

• ヒューズ
• ヒューズホルダー
• ターミナル
• バスバー
• Switching devices

Solar radiation can further increase enclosure temperature.

Component ratings and derating should reflect the actual internal operating environment.

IP Rating Is Not Enough

A high ingress-protection rating is important, but it does not prove that a combiner box has been correctly designed.

Electrical safety also depends on:

• Internal spacing
• 熱管理
• Component coordination
• ケーブル配線
• Connection quality

The complete assembly should be evaluated.

12. Inverter Coordination

有効 太陽光発電用インバータの保護 requires the PV array voltage, current and external protection architecture to coordinate with the inverter or other power conversion equipment.

Important inverter parameters may include:

• Maximum DC input voltage
• MPPT voltage range
• Maximum input current
• Maximum short-circuit current
• Number of MPPT channels
• Number of inputs
• Internal DC protection

Do Not Confuse MPPT Voltage with Maximum Input Voltage

The MPPT range describes the inverter’s normal operating range.

It is not the same as the maximum permissible DC input voltage.

Cold-weather open-circuit voltage must be checked separately.

Check Current Limits

Modern PV modules may have relatively high operating and short-circuit currents.

A string arrangement can be acceptable from a voltage perspective while exceeding the inverter’s current limitations.

Both voltage and current must be reviewed.

Verify Internal Protection

Some inverters include:

• DC SPD
• 直流スイッチ
• Fuse functions
• Insulation monitoring

These functions should be checked against actual manufacturer documentation.

Do not assume every inverter provides the same internal protection architecture.

13. Inspection and Documentation

Documentation, commissioning tests and inspection for grid-connected PV systems are addressed more specifically by IEC 62446-1.

Correct design does not eliminate installation errors.

Documentation, commissioning and inspection are therefore essential.

Important system documentation may include:

• Single-line diagrams
• String configuration
• Module data
• Inverter data
• Protection-device ratings
• Cable information
• Isolation points
• Earthing arrangements

Documentation should match the installed system.

Commissioning Inspection

Inspection should look for:

• 極性が正しくない
• 接続の緩み
• 損傷したケーブル
• Incorrect protection ratings
• Incorrect switch wiring
• Poor cable support
• Water-entry risks

The objective is to verify both electrical design and installation quality.

Developing Failures

Many PV electrical failures develop gradually.

例を挙げよう：

• Increasing connection resistance
• Terminal heating
• Connector deterioration
• SPD end-of-life
• 水の浸入
• 腐食

Preventive, corrective and performance-related maintenance practices are addressed by IEC 62446-2.

Periodic inspection can help identify problems before they become major failures.

14. Common IEC 62548 Design Mistakes

Mistake 1: Referring to IEC 62548 Without Checking the Edition

The project should identify the applicable publication and edition.

Mistake 2: Calculating Voltage Only from Normal Operating Conditions

Cold-weather open-circuit voltage must be evaluated.

Mistake 3: Assuming Every String Needs the Same Fuse Arrangement

String protection should reflect the actual fault architecture.

Mistake 4: Selecting a Fuse Only by Current Rating

Voltage, module limitations and installation conditions also matter.

Mistake 5: Using an AC Switch in a PV DC Circuit

The device must be suitable for the actual DC switching duty.

Mistake 6: Selecting Every Component Only by the Label “1500V”

Voltage rating alone does not define complete suitability.

Mistake 7: Ignoring Long Cable Routes

Cable length affects voltage drop, surge exposure and mechanical design.

Mistake 8: Assuming the Inverter Provides All Protection

Internal protection must be reviewed against the external array design.

Mistake 9: Choosing a Combiner Box Only by String Count

Current rating, thermal design and protection coordination also matter.

Mistake 10: Treating Compliance as a Product Certificate Exercise

Individually compliant components do not automatically create a correctly coordinated PV array.

15. Practical IEC 62548 Design Workflow

A practical PV array design workflow can be organized into eight steps.

Step 1: Collect Module Data

Record:

• ヴォック
• Isc
• Vmp
• Imp
• Temperature coefficients
• 最大システム電圧
• Relevant fuse limitations

Step 2: Define the Array Architecture

Determine:

• Modules per string
• 並列ストリング数
• MPPT allocation

Step 3: Calculate Maximum Voltage

Consider project temperature conditions and module characteristics.

Check all relevant DC equipment.

Step 4: Evaluate Current and Fault Conditions

レビュー

• ストリング電流
• Short-circuit current
• Parallel current contribution
• Inverter current limits

Step 5: Define Overcurrent Protection

Assess whether string protection is required.

Select appropriately rated gPV fuses or other protective devices.

Step 6: Design Cabling and Isolation

レビュー

• Cable rating
• Current capacity
• Routing
• 電圧降下
• DC isolation points

Step 7: Assess Surge and Combiner Protection

Coordinate:

• PV SPDs
• コンバイナー・ボックスの設計
• ヒューズ保護
• Switching devices

正しい DC fuse and DC SPD coordination is essential because overcurrent protection and transient overvoltage protection address different fault conditions.

Step 8: Verify the Complete DC Path

レビュー

PV Module → String → Cable → Protection → Combiner → Isolation → Inverter

No component should be evaluated independently from the surrounding circuit.

16. IEC 62548 Engineering Checklist

PV Modules and Strings

• Module electrical data reviewed
• Modules per string confirmed
• Parallel string quantity confirmed
• Temperature coefficients checked
• Module protection limitations reviewed

Voltage Design

• Maximum open-circuit voltage calculated
• Minimum temperature considered
• Inverter maximum DC voltage verified
• All DC equipment voltage ratings checked

Current and Overcurrent Protection

• String current reviewed
• Short-circuit current reviewed
• Reverse current evaluated
• String fuse requirement assessed
• gPV fuse coordinated with the protected circuit

DC Cabling

• Cable voltage rating suitable
• Current capacity checked
• Installation temperature considered
• Cable routing reviewed
• Mechanical support reviewed

Switching and Isolation

• Isolation points identified
• DC voltage rating confirmed
• Current rating confirmed
• Pole configuration verified
• Device location supports maintenance

サージ保護

• Surge risk assessed
• PV SPD type reviewed
• SPD voltage characteristics coordinated
• Installation location checked
• Connection path reviewed

コンバイナーボックス

• String input quantity correct
• Fuse ratings coordinated
• SPD suitable for the system
• Output current verified
• Thermal design considered
• Environmental protection suitable

インバータの協調

• Maximum DC voltage checked
• MPPT range checked
• Input current checked
• Short-circuit input limits checked
• Internal protection functions verified

17. Frequently Asked Questions

What is IEC 62548?

IEC 62548 is commonly used to refer to the international design requirements for photovoltaic arrays.

The current core publication is IEC 62548-1.

What is the current version of IEC 62548?

The current core edition is IEC 62548-1:2023, with Amendment 1 published in 2025.

The applicable edition and national adoption should be verified for each project.

Does IEC 62548 cover battery energy storage?

The main scope focuses on PV array design.

Battery energy storage requires additional standards and system-specific protection assessment.

Does every PV string need a fuse?

そうだ。.

The need for string overcurrent protection depends on parallel-string configuration, reverse current and the electrical limits of the circuit.

What is the difference between IEC 62548 and IEC 60364-7-712?

IEC 62548-1 focuses on PV array design.

IEC 60364-7-712 addresses electrical installation requirements associated with PV power supply installations.

They are related but not interchangeable.

Does IEC 62548 cover surge protection?

It addresses PV electrical protection at the array design level.

Detailed PV SPD requirements and selection principles are addressed more specifically by IEC 61643-31 and IEC 61643-32.

Can an AC isolator be used in a PV DC circuit?

Only if the device is specifically suitable and rated for the actual DC voltage, current and switching duty.

An AC rating alone does not demonstrate suitability for PV DC use.

Is IEC 62548 only for 1500V systems?

そうだ。.

Its design principles apply to PV array design more broadly.

However, 1500V systems require particularly careful review of voltage ratings, insulation and DC switching.

Is a compliant fuse enough to make a combiner box compliant?

そうだ。.

The complete assembly must be reviewed for:

• Component ratings
• Thermal conditions
• 内部配線
• Environmental protection
• プロテクション・コーディネーション

18. Final Engineering Recommendations

IEC 62548 should not be treated as a list of protection devices that must be installed in every photovoltaic system.

Its real engineering value is in system-level design.

Start with the PV module.

Define the string configuration.

Calculate the maximum voltage.

Evaluate current and reverse-current conditions.

Then coordinate:

• DC cables
• gPVヒューズ
• サージ保護装置
• 直流（DC）アイソレーター
• コンバイナーボックス
• インバーター入力

Every protection device should address a specific electrical risk.

A gPV fuse should be selected because an overcurrent condition has been identified.

An SPD should be selected because surge risk has been evaluated.

A DC isolator should provide a clearly defined isolation function.

A combiner box should integrate multiple circuits without creating thermal or coordination problems.

The central engineering lesson is:

PV array safety depends on coordinated electrical design, not on selecting protective devices independently.

For modern photovoltaic systems, the complete DC path should always be reviewed:

PV Module → PV String → DC Cable → Overcurrent Protection → Combiner Box → Surge Protection → Isolation → Inverter

That is the practical purpose of IEC 62548.