Iec 61439 Pdf Download
Rell Jette
Much has been made of the new, mandatory AS/NZS 61439 standard across Australia and New Zealand, but what does this really mean for the industry? Is this yet another expensive compliance issue, or will this have real benefit for our industry? And most importantly, does it go far enough?
AS/NZS 61439 is the new series of standards covering low-voltage switchgear and controlgear, and has been mandatory since May 2021. The AS/NZS 61439 is based on the International IEC 61439 standard and has been adopted to suit Australia and New Zealand.
The AS/NZS 61439 standards, replacing the previous standards which have been in place for nearly 20 years, impact manufacturers, assemblers and end users involved in all types of switchboard assemblies and usage, from distribution boards up to 250 amps, right through to main switchboards above 250 amps.
Under the new AS/NZS 61439 standard, the maximum temperature of the copper busbars in a switchboard is 105 degrees Celsius absolute above the ambient temperature in which the gear is operating. This improves the lifespan of the gear, and reduces the chance of overheating. By maintaining this temperature, safety standards are significantly improved and risk is better mitigated.
Arc fault mitigation is vital to protect personnel from injury, and damage to equipment, in the event of a fault. While the previous agreement on standards between manufacturer and customer have been retained, there are new additions. A notable change is that European arc fault containment testing can now be used for enclosed LV switchgear and control gear assemblies, as it is aligned with Australian standards.
In short, the new AS/NZS 61439 standards affect low voltage switchgear and control gear assemblies, and address some of the ongoing safety issues surrounding switchgear while remaining compliant with IEC 61439 standards.
Safety is a critical issue, both in terms of reducing potential injury to personnel, and also to reduce downtime for businesses. For business leaders, going above and beyond the minimum safety standards as specified by AS/NZS 61439 is imperative to ensure longevity in operator, equipment, and customer safety.
The purpose of the standard EN IEC 61439-2 (low-voltage switchgear and controlgear assemblies) is to harmonize as far as practicable all rules and requirements of a general nature applicable to low-voltage switchgear and controlgear assemblies (focus on power center) in order to obtain uniformity of requirements and verification for assemblies and to avoid the need for verification to other standards.
This three-part webinar series will take a deep dive into IEC 61439-1 and 61439-6, which defines the service conditions, construction requirements, technical characteristics and verification requirements for low voltage (LV) busbar trunking systems. It serves as a reference for the construction of electrical LV busway systems. IEC 61439 fully satisfies the requirements of designers and users of the new generation LV busway in the safety of persons and equipment, electrical availability, long-term reliability and conformity.
A higher quality electrical panel design and components also prevents a loss of service and associated downtime costs, saving end users money. For specifiers, this means the product is more reliable and business, therefore, is better.
Here, I will go over another path to improve reliability and functionality: ensuring proper insulation. Having the correct insulation means that even in extreme situations such as abnormal heat and fire, the material acts as a resistor, an important factor to prevent a damaging arc flash.
These tests verify that the material still acts as an acceptable insulator even when stressed by environmental conditions. In turn, that robustness means that the enclosure, panel and entire system will function as designed for years to come.
Regarding resistance to normal heat, IEC 61439 10.2.3.2 states that the original manufacturer will verify that the insulating materials do not change mechanical performance at temperatures of 125o C for current-carrying parts and 70o C for everything else. Following these guidelines guarantees performance during the life of the panel. Because of the temperature requirements, plastic insulation cannot be part of a compliant electrical panel. Normally, plastic insulation may appear less expensive, but it is not once the heat and fire resistance performance are considered.
As for abnormal heat and fire, IEC 61439 10.2.3.3 says the manufacturer will verify insulator properties when subjected to temperatures of 960o C for live, current carrying parts and 650o C for all other parts. (See below for an example illustration of how such a test is done.)
These tests for UV resistance, normal heat and abnormal heat ensure the quality of the insulating material. As a result, they assure panel specifiers that the quality of the final system will not be compromised over time by the weather and environmental conditions. So, the quality of the panel and enclosure stays at a level comparable to that when the system was new.
One potential area of confusion under the previous IEC 60439 standard was a difficulty in understanding who was responsible for specific types of safety and performance verification. The new IEC 61439-1 clearly identifies the various parties involved in specifying and manufacturing equipment and assemblies, along with their responsibilities, as follows:
This part 1 of IEC 61439 lays down the definitions and states the service conditions, construction requirements, technical characteristics and verification requirements for low-voltage switchgear and controlgear assemblies. This standard should be read in combination with one other part of IEC 61439, which consists of the specific requirements for a certain type of low-voltage switchgear and controlgear assembly.
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In this article we aim to look into some of the compliance requirements of BS EN 61439-3 and the responsibilities manufactures have to fulfil before certification is granted. As such, Contactum is proud to be able to share excerpts taken directly from its Defender 2 test reports.
Certification to BS EN 61439-3 requires a variety of tests to be performed, with certification only granted on successful completion of each test. These tests are onerous and designed to prove the unit is able to perform way past its normal expected operational design characteristics.
The test specimen is conditioned for at least 24 hours at a temperature between 15C and 35C and a relative humidity between 45% and 75%. Once removed from the conditioning atmosphere, the test specimen is tested within 30 minutes.
The wrapping tissue and the wooden board to be placed underneath the test specimen are specified in 5.3 of IEC 60695-2-10. They are conditioned for a minimum of 24 hours at a temperature between 15C and 35C and a relative humidity between 45% and 75%.
The protection against access to dangerous areas and access of foreign particles, as well as ingress of water, is verified, and the IP code IP2XC is then assigned. IP4X is also assigned, but only for the top of the unit.
IP4X in the top, according to the first characteristic 4, the access probe of 1mm diameter and 100mm length applied with a force of 1 N 10% shall not give access to dangerous mechanical or live parts.
The temperature of the different parts was measured by thermocouples type K. When this test is performed, a load is connected to the outgoing breakers, as per the table. The temperature is monitored for heat rise.
This test was performed according to BS EN 61439-3, Clause 10.11.5. The test object is placed in a support with cotton of about 34 g/m2 placed in all the openings that might be susceptible of emitting gases.
The correct working of the residual current device is verified by supplying with a voltage that is 0.85 times the nominal voltage. The test is performed to units of maximum and minimum rating for any different outgoing unit tested.
EN61439-2 refers to the 'Internal separation of ASSEMBLIES by barriers, or partitions', Table 104. This clause concerns methods of separating busbars and 'functional units' from one another when installing electrical control systems. This can be done by fitting barriers between the units, or by mounting them in separate compartments.
Note: These forms of separation are not relevant to arc fault containment which is not the subject of this specification, and would be subject to agreement between the manufacturer, and the client.
* This information is correct at the time of this publication. Sandford Electrical Services Ltd cannot be held responsible for any changes that occur. It is the responsibility of the user to check with the relevant standard at the time of use.
Terminals for external conductors located in the same compartment as the associated functional unit. Busbar separation is achieved by insulated coverings, eg. Sleeving, wrapping or coatings. Cables may be glanded elsewhere.
Terminals for external conductors located in the same compartment as the associated functional unit. Busbar separation is achieved by metallic, or non-metallic, rigid barriers, or partitions. Cables may be glanded elsewhere.
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