IEC TR 63225:2019

Incompatibility of connectors for DC-application in photovoltaic systems

IEC TR 63225:2019 highlights the problem of incompatibility of connectors for DC-application in photovoltaic systems (DC connectors) produced by different manufacturers. It addresses four particular issues in that context:
background information on incompatibility of DC connectors from different manufacturers;
observations and challenges concerning the handling of DC connectors from different manufacturers;
stakeholders concerned by the incompatibility of DC connectors;
recommendations for long-term standardization and interim measures to address incompatibility of DC connectors

General Information

• Status: Published
• Publication Date: 12-Nov-2019
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 27.160 - Solar energy engineering
• Technical Committee: TC 82 - Solar photovoltaic energy systems
• Current Stage: PPUB - Publication issued
• Start Date: 13-Nov-2019
• Completion Date: 14-Nov-2019

Overview

IEC TR 63225:2019 - Incompatibility of Connectors for DC-Application in Photovoltaic Systems is a technical report published by the International Electrotechnical Commission (IEC). This document addresses the significant issue of incompatibility between DC connectors used in photovoltaic (PV) systems when sourced from different manufacturers. It provides background insights into the causes of incompatibility, discusses associated risks and stakeholder concerns, and outlines both immediate and long-term strategies to enhance connector compatibility and overall PV system safety.

Key Topics

• Incompatibility of DC Connectors: The report highlights how DC connectors, despite similar appearances (e.g., commonly used MC4-type connectors), often lack true interoperability when produced by different manufacturers. Variations in materials, mechanical design, and manufacturing tolerances can compromise system safety.
• Safety and Reliability Issues: Mismatched connectors may increase electrical resistance, accelerate degradation, and can be a leading cause of fire hazards in PV installations. This is compounded by claims of “compatibility” by some manufacturers, which may be misleading.
• Stakeholders Affected: Key stakeholders include PV system owners, building residents, module manufacturers, inverter and cable producers, PV installers, and insurance companies. Each group faces unique risks and responsibilities due to the lack of uniform connector standards.
• Recommendations for Standardization: IEC TR 63225:2019 calls for the development of a common interface standard for DC connectors, emphasizing the need for standardization of critical features and quality management systems to ensure long-term compatibility and safety.
• Interim Measures: The document suggests practical steps for manufacturers, installers, and system owners to minimize risks until comprehensive standards are established. These include improved transparency, avoiding claims of “MC4 compatibility,” and facilitating access to compatible connectors.

Applications

The guidance and recommendations in IEC TR 63225:2019 are highly relevant for:

• PV System Design and Installation: Ensuring only fully compatible connectors are used enhances system safety, reliability, and lifespan, and helps prevent fire hazards.
• Procurement and Supply Chain Management: Decision makers should prioritize sourcing PV modules and connectors from trusted suppliers who provide transparent information about connector types and compatibility.
• Product Warranty and Risk Management: Manufacturers and owners should clarify connector warranties and liability to avoid disputes arising from mismatched connectors and system failures.
• Standards Development Participation: Manufacturers, installers, and other stakeholders are encouraged to engage in future PV connector standardization activities to foster a safer and more interoperable market.
• Insurance and Compliance: Insurance providers can use this standard to assess technical risks more effectively and tailor coverage to reward safer, standards-compliant installations.

Related Standards

For comprehensive PV system safety and connector compatibility, the following IEC standards are closely related:

• IEC 62852: Connectors for DC-application in photovoltaic systems - Safety requirements and tests.
• IEC 61730-1: Photovoltaic (PV) module safety qualification - Part 1: Requirements for construction.
• IEC 62548: Photovoltaic (PV) arrays - Design requirements.
• IEC 60364-7-712:2017: Low voltage electrical installations - Requirements for solar PV power supply systems.

IEC TR 63225:2019 serves as an essential reference for addressing the incompatibility of DC connectors in PV systems, promoting safety, reliability, and the long-term success of solar installations worldwide.

Standards Content (Sample)

IEC TR 63225 ®
Edition 1.0 2019-11
TECHNICAL
REPORT
Incompatibility of connectors for DC-application in photovoltaic systems
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IEC TR 63225 ®
Edition 1.0 2019-11
TECHNICAL
REPORT
Incompatibility of connectors for DC-application in photovoltaic systems

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.160 ISBN 978-2-8322-7534-4

– 2 – IEC TR 63225:2019 © IEC 2019
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Background . 5
5 Observations . 7
6 Affected stakeholders . 7
7 Proposed course of action . 8
7.1 General . 8
7.2 Long-term aim . 8
7.3 Interim measures . 8
8 Conclusion . 9
Bibliography . 10

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INCOMPATIBILITY OF CONNECTORS FOR
DC-APPLICATION IN PHOTOVOLTAIC SYSTEMS

FOREWORD
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data of a different kind from that which is normally published as an International Standard, for
example "state of the art".
IEC TR 63225, which is a Technical Report, has been prepared by IEC technical committee 82:
Solar photovoltaic energy systems.
The text of this Technical Report is based on the following documents:
Draft TR Report on voting
82/1499/DTR 82/1552A/RVDTR
Full information on the voting for the approval of this Technical Report can be found in the
report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 4 – IEC TR 63225:2019 © IEC 2019
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the specific document. At this date, the document will be
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A bilingual version of this publication may be issued at a later date.

INCOMPATIBILITY OF CONNECTORS FOR
DC-APPLICATION IN PHOTOVOLTAIC SYSTEMS

1 Scope
This document highlights the problem of incompatibility of connectors for DC-application in
photovoltaic systems (DC connectors) produced by different manufacturers. It addresses four
particular issues in that context:
• background information on incompatibility of DC connectors from different manufacturers;
• observations and challenges concerning the handling of DC connectors from different
manufacturers;
• stakeholders concerned by the incompatibility of DC connectors;
• recommendations for long-term standardization and interim measures to address
incompatibility of DC connectors.
2 Normative references
IEC 62852, Connectors for DC-application in photovoltaic systems – Safety requirements and
tests
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 62852 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
DC connector
connector designed for use in DC circuits of photovoltaic systems, as defined in IEC 62852.
Note 1 to entry: This document generally refers to connectors of type MC4 or similar, and particularly products that
are often referred to as “MC4-compatible”.
3.2
compatible DC connectors
interoperable DC connectors
intermateable DC connectors
components which terminate conductors for the purpose of providing
connection to and disconnection from a suitable mating component under supervision of one
quality management system
4 Background
In the early years of terrestrial photovoltaics, a range of different DC connectors were available
on the market. They were of distinctly different designs and could not be connected between

– 6 – IEC TR 63225:2019 © IEC 2019
each other. In the early 2000s the connector type MC4 became more and more popular.
Manufacturers started to adapt their connectors to the MC4 type. However, no international or
consortia-based interface technical specifications for this connector type are available.
IEC 62852, often referred to in this context, is a product safety standard and is not intended to
test intermateability.
Several countries report that problems with DC connectors are a major cause for failure such
as fire hazards in PV systems. Reports from different testing laboratories have shown that DC
connectors from different manufacturers may not be safe to interconnect. Even if they meet
basic quality requirements in the short term, they may derate when connected to products from
different manufacturers.
Disregarding these circumstances, DC connectors are often declared by manufacturers as
being compatible with each other. This claim of compatibility is potentially misleading as it
suggests a safe interoperability of DC connectors from diff
...