Manufacturer ACTOM MV Switchgear has completed the final phase in the design and development of its AMV product range, which was successfully type-tested in 2022 to a rating of 17.5 kV, in under a year – from April 2024 to March 2025.

The first order for AMV24 was received from a leading mining company in April 2025. These developments follow the success of the with­drawable pattern air-insulated AMV12 product, launched over ten years ago.

“AMV is now available with rated voltages of 12 kV, 17.5 kV and 24 kV – as well as in single and double busbar format,” says MV Switchgear design and development manager Rhett Kelly.

“As with AMV12/17, the AMV24 1 250 A and 2 500 A panels were de­signed having panel widths of 800 mm and 1 000 mm, respectively, and a short-circuit rating of 31.5 kA. The AMV24 range has the same look and feel as the AMV12/17 range and is offered with an embedded pole vacuum interrupter circuit-breaker de­sign. It has been designed in full com­pliance with not only SANS 1885 but also SANS(IEC) 62271-200, the South African and international standards for medium-voltage metal-enclosed switchgear, respectively. Notably, the creepage distance offered is 20 mm/kV in accordance with SANS 1885. The ACTOM Current Electric DIN block-type 24 kV CT shell designs were specifically modified to incorporate ad­ditional creepage sheds and integrated flash-barriers.

Further, the cable termination compartment design fully complies with the requirements outlined in SANS 876, the standard that covers insulation requirements for cable ter­minations and conductors in air-filled enclosures. This standard requires that the switchgear cable compart­ments have sufficient height for the termination of three-core power cables, as is the common practice in South Africa. This aspect, together with the 20 mm/kV specific creepage, makes the AMV24 unique in the market when compared with other imported products, as these design requirements are not specified in the IEC switchgear standards, explains MV Switchgear technology development specialist Johan Jordaan.

“The AMV24 high-voltage compart­ment architecture and design classifica­tion is LSC2B-PM in accordance with SANS (IEC) 62271-200, offering the highest level of service continuity with full earthed metal partitioning between compartments. This means that an accessible high-voltage (HV) compartment, after being isolated, can be accessed with the adjacent panels, busbar and incoming cable compartment (where relevant) alive and with no electric field presence or influence from adja­cent HV compartments. This enables maintenance to be performed safely and with minimal interruption to the power supply of other custom­ers or parts of the network. Access to HV compartments during normal use is mechanically interlock-controlled – ensuring that it is only possible to open the compartment once the HV parts contained in the compartment being made acces­sible are isolated and earthed or are in the disconnected position with cor­responding shutters closed,” adds Kelly.

The internal arc classification (IAC) is AFLR 31.5kA for one second, offering the maximum tested level of safety to personnel on all sides of the switchgear (in other words, the front, lateral and rear). The inter­locks, operating interfaces and tools are the same throughout the AMV range, ensuring a consistent operating methodology with minimal additional training required for users.

Type testing of the 1 250 A and 2 500 A assemblies occurred between October 2024 and March 2025, result­ing in a certificate of conformity from TUV Rheinland, a well-established and respected international certification body.

“Notably, the 1 250 A short-circuit circuit performance and electric endurance testing was successfully completed on the same circuit-breaker, without any intermediate maintenance or exchange of the circuit-breaker, achiev­ing a circuit-breaker classification of E2 (with auto-reclose), S2 and C2. This marked the first time ACTOM MV Switchgear has tested a circuit-breaker to class S2 and E2 at 24 kV, making it suitable not only for direct overhead line connection but also for rapid auto-reclose applications.

“This circuit-breaker can, therefore, also be used in ACTOM HV Equipment’s outdoor “dog­box” solution in future, having full type-tested compliance to not only State-owned power utility Eskom’s indoor but also outdoor circuit-breaker specifications. Type testing to Class S2 not only requires the complete set of terminal fault test duties, but also a short-line fault test duty. In addition, the circuit-breaker was not only type tested for a first pole-to-clear factor of 1.5, but also of 1.3, enabling the switch­gear to be used in non-effectively and effectively earthed networks,” Kelly explains.