PD IEC/TR 61641:2014

What is PD IEC/TR 61641‒ Enclosed low voltage switchgear and control gear assemblies about? 

PD IEC/TR 61641 is an international standard that covers general specifications for low-voltage switchgear and control gear assemblies. 

PD IEC/TR 61641 gives guidance on the methods for testing the assemblies under conditions of arcing in the air due to an internal fault.  

The test procedure given in PD IEC/TR 61641 applies only: 

• To enclosed, floor-standing or wall-mounted low-voltage switchgear and control gear assemblies according to IEC 61439-2 (power switchgear and control gear assemblies – PSC ASSEMBLIES) 
• To situations when doors and covers of the ASSEMBLY are closed and correctly secured 

PD IEC/TR 61641 considers the test procedure for the effects of the internal overpressure acting on covers, doors, etc., and the thermal effects of the arc or its roots on the enclosures and of ejected hot gases and glowing particles. 

Note 1: The test procedure given in PD IEC/TR 61641 does not cover: 

• Other effects which can constitute a risk, such as toxic gases and loud noises 
• Conditions during maintenance work, open doors, or similar 
• Access to the top and bottom of the assembly 

Note 2: PD IEC/TR 61641 can be used as a reference for arc fault tests of other products, but adaptations of the test procedures and acceptance criteria can apply taking into account the specifics of such other assemblies or products. 

Who is PD IEC/TR 61641‒ Enclosed low voltage switchgear and control gear assemblies for? 

PD IEC/TR 61641 on Enclosed low voltage switchgear and control gear assemblies is useful for: 

• Manufacturers and suppliers of low-voltage switchgear and controlgear  
• Dealers and distributors of low-voltage switchgear and controlgear 
• Designers and developers of low-voltage switchgear and controlgear  
• Test/ service providers for low-voltage switchgear and controlgear 

Why should you use PD IEC/TR 61641‒ Enclosed low voltage switchgear and control gear assemblies? 

The IEC 61439 series gives rules and requirements for interface characteristics, service conditions, construction, performance, and verification of low-voltage switchgear and control gear assemblies, which are also called assemblies. 

PD IEC/TR 61641 serves the objective of achieving the safe operation of low-voltage switchgear and control gear assemblies under normal operating conditions as well as under abnormal operating conditions, e.g., the occurrence of overvoltage, overload, or short-circuit currents.  

PD IEC/TR 61641 demonstrates the technical specifications to assess the ability of the assembly in order to help the users to acknowledge and limit the risk of personal injury, damage of assemblies, and its suitability for further service as a result of an internal arcing fault.  

PD IEC/TR 61641 can be used as a guide when tests under different or more severe conditions are agreed upon between the user and the manufacturer. 

What’s changed since the last update? 

PD IEC/TR 61641:2014 supersedes PD IEC/TR 61641:2008, which is withdrawn. The main technical changes compared to the first edition are the following: 

• Arcing classes to define the different forms of protection provided against arcing faults; (i) personnel protection, (ii) damage restricted to part of the ASSEMBLY, and (iii) ASSEMBLY suitable for limited further service 
• Two levels of personnel protection afforded by ASSEMBLIES under arcing fault conditions; (i) for ASSEMBLIES installed in areas where access to the ASSEMBLY is restricted to skilled persons, and (ii) for ASSEMBLIES installed in areas where the area is accessible to ordinary persons 
• Option of individually insulating all live conductors to make the complete ASSEMBLY an arc ignition protected zone (referred to as an ‘arc free zone’ in previous editions of the technical report) 
• Arc fault protection front, back, and sides of an ASSEMBLY as the normal requirement 
• Minimum performance requirements for arc ignition protected zone