Benefits of Using IEC 61439 Standard in Electrical Busbar Systems
                     IEC 61439 Standard in
Electrical Busbar systems
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Preface
In the Electrical manufacturing industry ‘Standards’ which define clear rules are extremely necessary for safety, proper 
functioning & to ensure quality at all levels. All the rules and recommendation under standards have been derived through 
extensive real world testing which assures correct or proper functioning of an electrical installation.z
Not adhering to standards can result into grave electrical hazard affecting the end user.  Following standards ensures safe 
operation of the electrical installation for many years.
Introduction
The IEC/EN 61439 is the result of the work of technical committees and subcommittees composed of representatives of the full 
member national electrotechnical committees in Europe, each dealing with a particular subject in the entire range of Electrical 
products and assemblies. 
IEC standard 61439 covers low voltage switchgear and control gear assemblies. It is a replacement for the earlier 
IEC standard 60439 and is now the industry standard requirement for all low voltage switchgear and control gear panel 
assemblies. The new standard gives details on the requirements of products through testing and other verification methods 
especially at pre design stage.
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Why was the new standard created?
In the earlier IEC standard 60439, ‘Design verification’ was excluded, and therefore the respective roles of equipment 
manufacturers and panel builders were not clearly defined, so responsibility for ensuring compliance was equally difficult to 
pinpoint. .
How does this new standard add value to the OEM, Consultant, 
Designer and Panel Builder?
The designer, be it from the consultant, OEM or the Panel builder identifies the needs and constraints for design, installation, 
operation and up-gradation of the complete system right at the design stage.
He chooses the correct switch gear, cables, connectors, busbar products and other components as per the specifications that he 
intends to use in his final assembly. Before he takes it up for manufacturing, at the design stage itself he needs to be sure that his 
choice of components are proper and that when the components are fitted in the control panel or Distribution panel that they 
follow the IEC 61439 standard.
To ensure this the designer carries out the design verification by various software tools provided by manufacturer which allows the 
electrical designer to be sure of his installation at an early stage.
1) The verification of the design by actual testing himself or by third party labs & by the calculation via prescribed tools supplied 
by the product manufacturer.
2) Proper documentation of this design verification (e.g. test documentation, calculations) is then made by the prescribed tools 
provided by the manufacturer.
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The panel builder thus is not only responsible for the completed assembly but also responsible for:
•      The rating of the switchgear assembly according to the customer requirements.
•      The compliance with the design verification of the original manufacturer.
•      The declaration of conformity to the customer (Declaration of Conformity)
•      The marking and documentation of the assembly
•      The performance of the design verification and documentation
General information about IEC - 61439
 In IEC 61439 three verification methods are recommended
• First by test
• Second by comparisons
• Third with reference to design & by assessment.
This covers Assemblies integrated for Generation, Transmission & Distribution of Electrical Energy and assemblies designed for 
Electrical equipment all in the voltage range not exceeding 1000V AC or 1500V DC.
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Wöhner Busbar System and IEC 61439 standards
Wöhner has been synonymous with top performance and innovation in 
technology for over 88 years. With over 100 registered patents, the Wöhner 
group is well established worldwide as a competent and reliable partner for 
energy distribution, control technology and renewable energies.
Wöhner has made it easier for electrical designers to adopt the new standard 
through verification methods by specially designed software tools on their  
website, which can be used for saving costs & need for additional testing.
• Short circuit strength: Pre calculated & tested by third party (avoids 
own testing requirements)*
• Temperature rise test: Pre calculated & tested by third party (avoids 
own testing requirements) Cross Board Classic
• Current insulation: Creep-age distance and isolation voltage pre-tested 
according to standards
• Dielectric strength: By specification in product data sheet ( Flexible 
Busbar )
*If short circuit values are not taken in to consideration, during 
electrical fault there would be a serious fire hazard, harmful to 
everyone.
60 Classic
Wöhner provides the current carrying capacity of the busbar and short circuit 
withstand capability of the system by calculation method with special tools on 
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1. Tools for achieving IEC 61439
Wöhner provides following free online tools which can be used by designer/planners verify their own design and confer to all the standards 
under IEC 61439
1)   Software for own design verification making the installation IEC complaint
2)   Configurator tool to design and achieve the required Short circuit withstanding capability
3)   Current carrying capacity of a Busbar & busbar holder with respect to temperature of busbar & enclosure
4)   Di-electric strength of the assembly of Busbar in the electrical enclosure
Software for own design 
verification making the 
installation IEC complaint:
Wöhner provides special software 
which can be accessed under their 
website menu “Tools”  where 
designer can fill up the Verification by 
comparison with a reference 
construction using the checklist under 
this tool. And documentation can be 
made for final submission to end user 
conferring to IEC requirements. 
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2. Configurator tool to design and achieve the 
required Short circuit withstanding capability
A snap shot of configurator tool 
to achieve desired level of short 
circuit rating;
Wöhner configurator tool can be 
used to construct the power 
distribution and to achieve and 
maintain the desired short circuit 
withstanding capability of the 
system 
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3. To measure the Short circuit carrying capacity of a Bus bar 
system 
We can check short circuit strength of a Busbar 
system by the design tools provided by Wöhner  by 
the following simple steps:
The short circuit strength mainly depends on few 
parameters like size of the busbar, number of 
supports and distance between the busbar supports.
Example:
Using the  “design” tools by Wöhner we select the 
busbar support in the 60Classic 3P range (01500 
Wöhner part number) busbar size of 20mmx10mm, 
Decide that we will be using two numbers of busbar 
supports and that the distance between number of 
supports will be 300 mm by giving these inputs in 
the “design” tools we receive the short circuit 
strength of 53 KA. (refer screen shot 1)
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If we now change the 
distance between busbar 
support from 300 mm to 450 
mm by maintaining all other 
parameters same we receive 
short circuit strength as 43 
KA. 
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4. Current carrying capacity of Busbar systems by “design” 
tools
We can check the “Current carrying For example
capacity” of the Busbar systems by if we select busbar to be of the size 20mm x10mm, with a length of 2.4m – (Wöhner item 
the “design” tools provided by code -01624), and if we select air temperature of 35°C and busbar temperature of 85°C, we 
Wöhner by the following simple will  get the current carrying capacity 652A. (refer screen shot 3)
steps.
The current carrying capacity of 
Busbar depends upon the Air 
temperature allowable inside the 
electrical cabinet and Busbar 
temperature that the end User has 
prescribed as Safe to use.
On the Wöhner website, we need to 
select the size of the busbar, 
temperature of air permissible in 
the electrical panel based upon the 
user specifications and allowable 
temperature of busbar as desired 
by the designer and allowed by the 
end user. By giving these inputs we 
can get the current carrying 
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Now if we keep the size of the busbar and busbar An actual application photo of the 
temperature as constant and change the allowable air control panels using Wöhner products.
temperature from 35°C to 55°C. We will then receive the 
calculation of the current carrying capacity of the Busbar 
to be 508 A. 
With Wöhner products, Usage verification can be done right 
at the stage of design, Thus by using the IEC 61439 standard 
and with the examples mentioned above the Designer and 
the OEM manufacturer and the Electrical panel builder can 
design very good quality products. The End User is then 
provided a system which he can trust and be ensured about 
the Safety and reliability,
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Other features of Wöhner’s unique Busbar solutions:
•  Innovative design by Wöhner allows mounting of electrical switch 
gear directly on busbars saving expensive real estate in the electrical 
panel. Wöhner products guaranty safety & ease of assembly to our 
customers making the Assembly time reduce to 1/3rd  of the 
conventional assembly time. 
•  Copper Busbars are connected to cables & LV switchgear (100A-
1000A) without drilling the Busbars. Well-designed mounting adapters 
& cable clamps provide a systematic & compact power distribution 
panel along with all features like safety, ease of assembly, ease of 
maintenance, etc.
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Conclusions
“Electrical wiring & design are the most critical part of any electrical 
installation. Wöhner Busbar system solution are uniquely designed as 
per IEC 61439 standard, and provides for free risk free compliance to 
standard with best safety, quality & cost saving.”
Farook Merchant - MD Messung Group (Mega Distributor for Wöhner Products in India.)
“Working with world class standards brings International Quality to 
control panels manufactured by our customers. We are able to specify, 
test & guarantee to our customer; Critical specifications like Short 
circuit currents, temperature rise & di-electric strength as per IEC 61439 
standard. This new standard gives details on the requirements of 
Wöhner products through testing and other verification methods. It is 
intended to make up for some of IEC 60439’s shortcomings.”
Shrikanth Venkateshappa - International Key Account Manager, Wöhner.
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THANK YOU
Contact us
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