Type-Tested, Factory-Tested, Documented

IEC 61439 is the international standard for low-voltage switchgear and controlgear assemblies. It defines how an assembly’s design must be verified and how each finished unit must be checked before it is put into service. Exa Power engineers every assembly to this standard, treating it as the practical framework for building equipment that is safe, dependable and demonstrably compliant rather than as a label to be applied after the fact. The standard exists because a low-voltage assembly is only as good as the verification behind it, and that verification has to be real.

Compliance is achieved through a combination of design verification, drawn from the type-tested ABB systems we build on, and routine verification carried out on each assembly we produce. This two-part approach is the foundation of a compliant, dependable low-voltage assembly: the design is proven, and the individual build is checked.

The standard covers characteristics such as short-circuit withstand, temperature rise, dielectric properties, protective bonding and clearances. Building within ABB’s verified system means these design characteristics are established, and our job is to build faithfully within that system and verify the finished article.

IEC 61439 is built around two complementary forms of verification, and a compliant assembly needs both. Design verification establishes that the design of the assembly meets the requirements of the standard, covering characteristics such as temperature rise, short-circuit withstand, dielectric properties, clearances and creepage, and the effectiveness of the protective circuit. For an authorized panel builder, this is largely satisfied by building within the manufacturer’s type-tested system, because the system owner has already verified those design characteristics.

Routine verification is the second half, and it is the panel builder’s direct responsibility on every single assembly produced. It confirms that the individual unit has actually been built in accordance with the verified design and is safe to put into service. A system can be perfectly designed and still be wired incorrectly on a given day, which is exactly why routine verification exists. At Exa Power both halves are taken seriously: we build within the verified ABB design, and we verify every finished assembly before it leaves the facility.

Before any assembly leaves our facility it goes through routine verification as set out in IEC 61439. This is the systematic check that confirms the individual unit has been built correctly and is safe to energise. It covers the inspection of the assembly including wiring and, where appropriate, functional operation; the verification of insulation resistance or a dielectric test; and the checking of protective measures and the integrity of the protective circuit.

We also confirm that the assembly matches the approved drawings: that devices are the specified ratings, that labelling is correct and complete, that torques are applied and marked, and that the form of separation built is the form that was specified. These checks are recorded, and the routine-test records form part of the documentation package issued with the assembly, so the evidence of compliance travels with the equipment rather than living only in the factory.

The intent is simple and practical: catch any build error in the factory, where it is cheap and quick to correct, rather than on site, where it is disruptive and expensive.