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Home / Download Center / Electrical Engineering Books and Technical Guides / Power substation guides / IEC 61439 standard for low voltage switchgear and controlgear assemblies

Introduction to IEC 61439

IEC 60439, the standard for low-voltage switchgear and controlgear assemblies, was under restructuring from the last decade. The new series of IEC 61439 standards were published in January 2009. This standard has brought considerable clarity in technical interpretation.

IEC 61439 standard for low voltage switchgear and controlgear assemblies
IEC 61439 standard for low voltage switchgear and controlgear assemblies (on photo: MNS unit substation transformer busbar connections; credit: controlequipment.ie)

The Standard IEC 61439 explicitly outlines the verification types required from both entities engaged in the final conformity of the solution: the Original Manufacturer, who ensures the design of the LV assembly system, and the Assembly Manufacturer, accountable for the switchboard’s final conformity.

IEC 61439 standard follows the philosophy of IEC 60947 series i.e. IEC 61439-1 is ‘General Rules’ standard to be referred to by subsidiary product parts of IEC 61439 series. The IEC 60439 standards were ambiguous about how to assess compliance of partially type tested assemblies.

As a result manufacturers and testing bodies often treated partially type-tested assemblies differently.

One of the main features of IEC 61439-1 is that the discrimination between Type Tested Assemblies (TTA) and Partially Type Tested Assemblies (PTTA) has been eliminated by the verification approach.

The three different but equivalent types of verification methods are introduced and these are:

  1. Verification by Testing
  2. Verification by Calculation/Measurement
  3. Verification by Design rules

The requirements regarding short circuit performance, temperature rise, dielectric properties and rated diversity factor have been covered in more detail.


Salient features of IEC 61439

1. Verification of temperature rise

  • For multiple compartment assembly, verification by calculation can be done up to rated current of 1600 A only.
  • Assemblies, verified by design rule from a similar tested assembly, should comply with the following:
    • Functional units shall belong to the same group as functional unit selected for test.
    • Same type of construction.
    • Same or increased overall dimensions.
    • Same or reduced internal separation.
    • Same or reduced power losses in the same section of assembly.
    • Same or reduced number of outgoing circuit for every section.
  • Rated diversity factor (RDF) is elaborated in more details with incoming and outgoing circuit diagrams.
  • The average ambient temperature for the duration of test shall not exceed 35 °C.

Watch Video – Webinar: IEC Standards 61439 – 2 Edition 3


2. Short circuit withstand test

Verification of assembly by design rules is permitted, if;

  • Following requirements are greater than or equal to reference design
  • Cross-sectional dimensions of the busbars and connections
  • Spacing of the busbars and connections
  • SCPDs are equivalent, i.e. of the same make with the same or better I2t based on the device manufacturer’s data

Following requirements are less than or equal to reference design:

  • Short circuit rating of each circuit
  • Busbar supports spacing
  • Length of unprotected live conductors of each non-protected circuit

Following requirements are same as that of reference design:

If all the above requirements are satisfied, than further verification by calculation or actual testing is not required.


3. Power frequency withstand voltage

The values of dielectric test voltage are reduced corresponding to rated insulation voltage. Refer Table 3,

Table 3
Table 3

4. Impulse voltage withstand test

Verification is mandatory either by test or by design rules. Test is not required when clearances in the assembly are 1.5 times the specified value in Table – 4.

Table 4
Table 4

5. Degree of protection

The IPX1 to IPX6 tests on an assembly are deemed to be failure if water comes into contact with electrical equipment housed within the enclosure. Requirements for ‘empty enclosures for assemblies (IEC 62208)‘ have been incorporated in the standard.


6. Mechanical operation

Rated numbers of operating cycles have been increased from 50 to 200.


7. Protection provided by barriers

The protection provided by horizontal top surfaces of easily accessible barriers is changed from IPXXB (the protection of person against access to hazardous parts with finger) to IPXXD (the protection of person against access to hazardous parts with wire).


8. Cross-section area of neutral

  • 100% for phase cross section of 50% up to 16 mm2
  • 50% for phase cross section area above 16 mm2, with a minimum of 16 mm2
  • For conductor other than copper, the cross section should be greater than equivalent copper conductor

9. Additional Tests in IEC 61439

Resistance to corrosion Test

Purpose: To ensure that deterioration of metallic component caused by corrosion shall not impair the mechanical strength of switchboard.

Procedure: The test is carried out on a typical switchboard enclosure or on a representative sample showing the same constructional details.

  • 6 cycles of 24 hr each to Damp Heat Cycling Test according to IEC 60068-2-30 at (40±3)°C at relative humidity of 95%.
  • 2 cycles of 24 hr each to Salt Mist test according to IEC 60068-2-11 at temperature of (35±2)°C.

Assessment Criteria:

  • The mechanical integrity shall not be impaired.
  • Doors, hinges, locks, etc. shall work without abnormal effects.
  • Seals shall not damage.
  • There shall be no iron-oxide, cracking or other deterioration more than that allowed by ISO 4628-3 for degree of rusting Ri1.

Verification of Thermal Stability

Purpose: To check the thermal properties of the enclosure

Procedure: The specimen is kept in a heating chamber at 70°C for 7 days. After that the sample is kept at ambient temperature for 4 days.

Assessment criteria: The sample shall show no cracks nor shall the material become sticky or greasy. Sample is pressed with the forefinger wrapped in a dry cloth with a force of 5 N; no traces of cloth shall remain on the sample.


Verification of resistance of insulating materials to heat

Purpose: To ensure the properties of insulating material to normal heat

Procedure:

  • A ball pressure test apparatus is used to verify the suitability of insulating materials.
  • The test shall be carried out on an insulating material of minimum 2 mm thickness.
  • The test shall be made in a heating cabinet at a temperature as stated below:
    • parts supporting live components − 125°C
    • other parts − 70°C
  • After 1 hr, the sample is removed and cooled within 10 s to approx. room temperature by immersion in cold water.

Assessment criteria: The diameter of the impression caused by the ball shall be measured and shall not exceed 2 mm.


Resistance to abnormal heat & fire (Glow Wire Test)

Purpose: Glow wire test checks the capability of insulation material to handle thermal stresses produced by sources of heat or ignition.

Procedure:

  • Sample: Thinnest wall thickness of the completed application.
  • Pre-treatment: 24 hours at 23°C at 50% RH.
  • Temperatures of glow wire: 550, 650, 750, 850 or 960 degrees C (depending on the relevant specification).
  • Force: 1 N
  • Contact time: 30 s

Assessment criteria:

  • There is no flame and glowing on the sample or flames/ glowing of the sample extinguish within 30 s.
  • The cotton or the paper underlay doesn’t ignite or burn.

Resistance to UV radiation

Purpose: The UV radiation causes deterioration of synthetic material use for enclosures.

Procedure:

  • UV Test according to ISO 4892 — 2 method A; 1000 cycles of 5 min of watering and 25 min. of dry period with xenon lamp providing a total test period of 500 hrs.
  • The value of temperature and humidity for the test are (65±3)°C and (65±5) %.

Assessment criteria:

  • Adherence of synthetic material (according to ISO 2409) shall have minimum 50% retention.
  • Sample shall not show cracks or deterioration visible to normal or corrected vision without any additional magnification.
  • This test is not required if synthetic material supplier demonstrates that materials of same thickness or thinner comply with this requirement.

NOTE: This test is applicable only for enclosures and external parts of ASSEMBLIES intended to be installed outdoors.


Lifting

Purpose: To ensure that there should be no damage to the panel during transportation & installation.

Procedure: The test is carried out on a sample having weight 1.25 times its maximum shipping weight. From a standstill position, the ASSEMBLY shall be raised smoothly without jerking in a vertical plane to a height of (1.0.1) m and lowered in the same manner to a standstill position. This test is repeated a further two times. After this the ASSEMBLY is raised up and suspended for 30 min at a height of (1±0.1) without any movement.

Following this test the ASSEMBLY shall be raised smoothly without jerking from a standstill position to a height of (1±0.1) m and moved (10±0.5) m horizontally, then then lowered to a standstill position.

This sequence shall be carried out three times at uniform speed, each sequence being carried out within 1 min.

Assessment criteria: During the test, with the test weightsin place, the ASSEMBLY shall show no deflections and after the test show no cracks or permanent distortions visible to normal or corrected vision without additional magnification, which could impair any of its characteristics.


Mechanical Impact Test

Purpose: This test measures resistance of an enclosure towards external mechanical impact. The degree of protection provided by an enclosure against impacts is indicated by the letters IK followed by two digits depending on its ability to withstand the impact (as per IEC 62262).

Procedure:

  • Number of impacts on each exposed face shall be five unless otherwise specified in relevant product standard.
  • The impacts shall be evenly distributed on the faces of the enclosure under test.
  • At the surrounding of any point of enclosure, not more than three impacts shall be applied.

Assessment Criteria:

  • Structural integrity shall be maintained.
  • Degree of protection (IP) shall be unaffected.
  • Functionality of electrical products shall not be hampered.

NOTE: Mechanical Impact test is not applicable to low voltage power switchgear and controlgear (PSC) assemblies.


Marking

Purpose: To ensure that the markings are legible.

Procedure:

  • Marking made by moulding, pressing, engraving or similar shall not be submitted to the following test.
  • The test is made by rubbing the marking by hand for 15 s with a piece of cloth soaked in water and than for 15 s with a piece of cloth soaked with petroleum spirit.

Assessment criteria: After the test the marking shall be legible to normal or corrected vision without additional magnification.


The objectives of IEC 61439

There are three fundamental objectives that can be accomplished by the implementation of all of the verifications that are suggested by the standard IEC 61439: safety, continuity of service, and conformity with end-user requirements.

Let’ list the main characteristics of each.


1. Safety

1.1 Capability to withstand voltage stress

Requirements and design specifications: Insulation designed to withstand prolonged voltages, transient, and temporary overvoltages ensured through appropriate clearances, creepage distances, and robust insulation.

Verification of design:

  • Clearance and creepage distance measurements
  • Power frequency dielectric test
  • Impulse withstand voltage test, when clearances exceed specified values

Routine verification:

  • Inspection of clearances (in accordance with design specifications and creepage distances)
  • Power frequency dielectric test

1.2 Current-carrying capability

Requirements and design specifications:

  • Prevent burns by controlling extreme heat:
  • When a single circuit is constantly loaded to its rated current, and
  • When a circuit is continuously loaded to its rated current multiplied by its rated diversity factor.

Verification of design:

  • Temperature rise tests
  • Or comparison with a validated reference design, under rigorous circumstances
  • Or, under highly constrained circumstances, calculations with safety margins (including a 20% derating of devices)

Routine verification:

  • Visual inspection
  • Random verification of tightness

1.3 Short-circuit withstand capability

Requirements and design specifications: Withstand short-circuits due to protective devices, coordination measures, and the ability to withstand the strains imposed by short-circuit currents across all conductors.

Verification of design:

  • Short-circuit tests (Icc and Icw) of the main circuit, including the neutral conductor, and of the protection circuit
  • Or comparison with a tested reference design under restrictive conditions

Routine verification: Visual inspection


1.4 Electric shock protection

Requirements and design specifications: Hazardous live components are inaccessible (basic insulation protection), while accessible conductive components pose no risk to life (fault protection and continuity of protective equipotential bonding).

Verification of design:

  • IP XXB test and insulating materials verification
  • Mechanical operation tests
  • Dielectric properties verification
  • Measurement of the resistance between each exposed conductive part and the PE terminal
  • Short-circuit strength of the protection circuit

Routine verification:

  • Visual inspection of basic and fault protection
  • Random verification of tightness of the protective circuit connections

1.5 Protection against fire or explosion hazard

Requirements and design specifications: Protect persons against the fire hazard: resistance to internal glowing faulty elements, through selection of materials and various design provisions.

Verification of design:

  • Glow wire test
  • Special test according to IEC TR 61641, where specified

Routine verification: None


2. Continuity of service

2.1 Maintenance and modification capability

Requirements and design specifications: Ability to maintain supply continuity while ensuring safety during assembly maintenance or modification. Via fundamental and fault protection, along with optional detachable components.

Verification of design:

  • IP tests
  • Mechanical operation tests (especially for removable parts)

Routine verification:

  • Efficiency of mechanical actuation components
  • Verify the protection of individuals from electrical shocks

2.2 Electromagnetic Compatibility (EMC)

Requirements and design specifications: Ensure optimal operation and prevent the development of electromagnetic compatibility (EMC) disturbances by integrating electronic devices that adhere to the applicable EMC standards and by executing their proper installation.

Verification of design:

  • EMC tests according to product standards or generic EMC standards

Routine verification: None


3. Conformity with end-user requirements

3.1 Capability to operate the electrical installation

Requirements and design specifications:

Properly function, according to:

  • The The electrical diagram and the specifications (voltages, protection coordination, etc.) by selecting, installing and wiring the appropriate switching devices.
  • The specified operating facilities (Access to Man-Machine Interfaces, etc.) through accessibility and identification.

Verification of design:

  • By inspection
  • Impulse withstand voltage test of isolating distance for optional withdrawable units

Routine verification:

  • Visual inspection
  • Effectiveness of mechanical actuating elements and function test (where relevant)

3.2 Capability to be installed on site

Requirements and design specifications: Withstand handling, transport, storage and installation constraints, and be capable to be erected and connected through selection or design of the enclosure and the external terminals, and by means of provisions and documentation.

Verification of design:

  • By inspection
  • Lifting test, taken from IEC 62208

Routine verification: Number, type and identification of terminals for external conductors


3.3 Protection of the Assembly against environmental conditions

Requirements and design specifications: Protect the Assembly against mechanical and atmospheric conditions through selection of materials and various design provisions.

Verification of design:

  • IP test
  • IK test
  • Corrosion test
  • UV test (outdoor only)

Routine verification: None

Title:Introduction to IEC 61439 – A new standard on Switchgear and Controlgear Assemblies
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Introduction to IEC 61439 - A new standard on Switchgear and Controlgear Assemblies
Introduction to IEC 61439 – A new standard on Switchgear and Controlgear Assemblies

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29 Comments


  1. SPARSH AGRAWAL
    Nov 26, 2023

    Membership Procedure and charges, please.


  2. ASHU
    Dec 02, 2022

    Hi Sir

    I am looking for IS/IEC 61439 Part 1 & 2 rule for LT panel ,Please provide Design verification process As per IEC 61439 -1&2 for LT Panel and authorized agency who carried out the design verification processor for LT Panel Board outdoor/indoor type,who has given IEC 61439 cetificate .


  3. Jason kan
    Aug 29, 2022

    Can anybody advise for this request by our customer.
    He wanted a distribution board 300A 50KA 1sec type test board.
    I don’t know about type board requirements.

    Thank You


    • SURAJ YADAV
      Mar 28, 2025

      You can go with siemens SIEPAN panel. Could u provide more information for the unpstream on my email? I will do the calculations accordingly and get back to you with efficient, flexible, reliable and sustainable design


  4. Nutan Changale
    Jul 25, 2022

    Hi sir,

    I am looking for IEC 61439-2:2020 rules details for control panel.


  5. Sachin Singh
    Feb 08, 2022

    Hi

    I am looking for I.E.C 61439-1 General rules to see if my automation panel complies

    Thank you


  6. YOGESH GOWDA
    Feb 01, 2022

    HI, we are panel manufacturer, and regular doing Panel Works, Automation etc, for our company we required IEC61439 CERTIFICATE, HOW TO GO AHEAD WITH THIS
    REQUEST YOU TO KNOW IS THE PROCEDURE


    • Gautam Shukla
      Feb 19, 2022

      We are providing technical consultancy for design and engineering of panel to be tested in laboratory as per IEC 61439. Do contact on given email ID.


      • Rudranarayan Satapathy
        May 05, 2022

        Please share your e mail id & contact details for further discussion.


    • Tula Srinivas
      Jul 07, 2022

      Its a type tested assemblies.
      You have prototype test certificates only once.
      You have to submit the same certificates to any of your customer.
      Every time you will not get the certificates from CPRI.


  7. G.BHAKTHA VALSALAM
    Dec 03, 2021

    kindly send detail technical of ICE 61439


  8. Gabriel
    Apr 27, 2021

    Dear instructor, can you send me please the standards IEC 61439 from 1 to 7, I’ll appreciate it.


  9. Myint Maung
    Nov 16, 2020

    Thanks for information


  10. Sameera
    Oct 13, 2020

    Can any one share the IEC 61439 including all parts?


    • Av selvan
      Apr 27, 2021

      can any one send me test procedure or iec 61439


      • Tula Srinivas
        Jul 07, 2022

        Dear its a type testing assembly at CPRI, banglore.
        To update you its very simple, you can download IEC from online, otherwise its SOP at CPRI banglore.


  11. vinod thangappa
    Aug 05, 2020

    Hi to all,

    I need to know about which standard to be followed for Power/control panel wiring refer to IEC derivatives.


    • Tula Srinivas
      Jul 07, 2022

      Referring to the IEC60947 control panel manufacturing standards, you should follow the wiring practices.
      Aside, wiring standards for internal control panel to be followed as IS standards too.


  12. Sameera
    Jun 03, 2020

    Hi Edward,

    I am an electrical consultant in Sri Lanka. Can you please send me IEC 61439 standard all parts including busbar trunking.

    Thank you,
    Sameera


  13. Mangesh Dhepe
    May 12, 2020

    Hi,
    I want Electrical Panel Checklist Sample… Anyone Can Help Me ??


  14. Rajeev Pandey
    Apr 27, 2020

    यह हमारे Technical Improvement के लिए अच्छा Portal है.। मैं इस Electrical Engineering Portal को.10 में से 10 नंबर दे रहा हूँ।
    राजीव पांडेय
    Electrical Engineer (Maintenance)


  15. ศิริพร พิทักษ์กุล
    Jun 10, 2019

    Thank you very much.


  16. mohamed
    Dec 14, 2017

    thank you


  17. wc_foronda
    Oct 17, 2013

    problem with file format, can’t open file after download..

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