What is the difference between IEC 60331 and 60332?

Introduction

In the field of fire protection, there are various international standards that ensure the safety and reliability of electrical cables. Two such prominent standards are IEC 60331 and IEC 60332. Although these standards may seem similar at first glance, they serve different purposes and have distinct criteria for evaluating cable performance in the event of a fire. This article aims to shed light on the key differences between IEC 60331 and IEC 60332.

IEC 60331: Fire resistant cables

IEC 60331 specifies the test methods and requirements for electric cables to maintain circuit integrity during exposure to fire. This standard focuses on the ability of cables to transmit electrical signals even in extreme fire conditions, allowing people to safely evacuate buildings and facilitating firefighting operations. Cables that comply with IEC 60331 sustain their functionality for a defined duration specified in the standard, typically 30 minutes or 120 minutes.

IEC 60332: Flame retardant cables

On the other hand, IEC 60332 addresses the flammability properties of cables and their tendency to propagate flames along their length. The objective of this standard is to minimize the risk of fire spreading through cables that are exposed to an open flame. Cables complying with IEC 60332 must suppress the spread of fire, self-extinguish once the source of flame is removed, and limit the production of smoke and toxic gases.

Differences in test conditions

The testing procedures for IEC 60331 and IEC 60332 also differ. To evaluate fire resistance according to IEC 60331, a cable sample is subjected to a direct flame at a specified temperature and duration. The cable's electrical performance is then assessed during and after the fire exposure. In contrast, IEC 60332 evaluates flame spread by exposing horizontal or vertical cable samples to an open flame and measuring factors such as flame propagation distance, burning time, and afterflame time.

Conclusion

In summary, while IEC 60331 focuses on maintaining electrical circuit integrity during a fire, IEC 60332 primarily addresses the flammability characteristics of cables. Understanding the difference between these two standards is crucial for selecting the appropriate cables based on specific safety requirements. By adhering to these global standards, manufacturers can ensure the reliability and safety of electrical cables in various fire scenarios.