Browsing by Author "Bonner, Mark James."

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Safety implications of the introduction of a specially tested assembly into the South African national standard for low-voltage assemblies.
(2004) Bonner, Mark James.; Ijumba, Nelson Mutatina.
Low-voltage switchgear and controlgear assemblies with a rated short-circuit withstand strength above 10 kA, are required, by law, to conform to the South African standard, SANS 1473-1 (Low Voltage Switchgear and Controlgear Assemblies: Part 1: Typetested, partially type-tested and specially tested assemblies with rated short-circuit withstand strength above lOkA). Standard SANS 1473-1 stipulates three categories of assemblies i.e. type-tested, partially type-tested and specially tested assemblies. The specially tested assembly is unique to the South African market, while the other two categories are stipulated in standard SANS IEC 60439-1 (Low Voltage Switchgear and Controlgear Assemblies: Part 1: Type-tested and partially type-tested assemblies), which is internationally accepted in many countries as the applicable low-voltage assembly standard. Standard SANS 1473-1 specifies seven type-tests for certification as a type-tested assembly (TTA), but specifies, at most, three type-tests for certification as a specially tested assembly (STA). The underlying purpose of a technical standard is to provide for the safety of people and property, with the purpose of the research being twofold: 1. To investigate if the testing requirements specified for a specially tested assembly (STA), in accordance with standard SANS 1473-1, are correctly applied, and do not pose any safety risks. 2. To investigate any safety risks that stem from the fact that four type-tests are excluded for verification as a specially tested assembly (STA), as opposed to the seven type tests required for verification as a type-tested assembly (TTA). The document highlights the technical inadequacies of an assembly that is certified as a STA, in accordance with standard SANS 1473-1, and the potential safety risks associated with this type of assembly classification.
Safety of low voltage switchgear assemblies in South Africa – Part 1.
(EE Publishers., 2005) Bonner, Mark James.; Ijumba, Nelson Mutatina.
A technical analysis was undertaken to investigate the safety implications of the introduction of the category Specially Tested Assembly (STA) into the South African standard SANS 1473-1:2003. The testing requirements specified for a Specially Tested Assembly (STA) are compared to the testing requirements specified for a Type-Tested Assembly (TTA), tested in accordance with standard IEC 60439-1:1999. The technical inadequacies and the potential safety risks associated with an assembly that is certified as a STA are exposed, and remedial measures proposed.
Safety of low voltage switchgear STAs in South Africa – Part 2.
(EE Publishers., 2005) Bonner, Mark James.; Ijumba, Nelson Mutatina.
This article is Part 2 of a two part article. Part 1 was published in the October 2005 issue of ENERGIZE. A technical analysis was undertaken to investigate the safety implications of the introduction of the category Specially Tested Assembly (STA) into the South African standard SANS 1473-1:2003.