What does AS/NZS 61439 really mean?

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.

The reasoning behind this change is to rectify the previous lack of checks in place to ensure switchboards were fit for purpose, which had significant injury repercussions throughout the industry. The new standards set new safety requirements, ensuring portability between Australia and global suppliers and maintaining compliance with IEC 61439 standards.

Let’s take a look at the three key areas of the AS/NZS 61439 standards: temperature rise test, arc faults, and verification, and see what’s changed:

Temperature Rise Test

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

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.

This testing includes:

1. Doors, covers, or other access points do not open
2. Parts do not fly off
3. Arcing does not create holes in the external faces of the enclosure
4. Flammable indicators placed around the perimeter of the tested equipment do not ignite
5. Protective circuits for accessible parts of the enclosure are still effective
6. The arc is confined to a defined area where it ignited, without propagation to other areas within the assembly
7. After clearing the fault, or after isolation or disassembly of the affected functional units in the defined area, emergency operation of the remaining assembly is possible.

Verification

Another key change to the AS/NZS 61439 standards is the introduction of ‘alternative and equivalent’ methods of design verification, which has replaced the categories of “type-tested assemblies (TTA)” or “partially type-tested assemblies (PTTA)”.

There are now three ‘alternative and equivalent’ design verification options which can be used:

1. Verification by testing performed on a sample of an assembly or on parts of assemblies to check that the design satisfies the requirements of the applicable assembly standard.
2. Verification by comparison involves structured comparison with a design that has been tested.
3. Verification by assessment, where calculations are applied to a sample of an assembly to demonstrate the design satisfies the requirements.

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.

Find out more about Eaton’s xEnergy Main low-voltage switchboard system here.