Iec 61439-6 Pdf [updated] Page

The standard eliminates the old distinction between "type-tested" (TTA) and "partially type-tested" (PTTA) assemblies, replacing them with three equivalent verification methods: Verification by Testing : Physical tests conducted on representative samples. Verification by Calculation/Measurement

IEC 61439-6 specifically covers the definitions, service conditions, construction requirements, and verification needs for low-voltage busbar trunking systems iec 61439-6 pdf

Form of separation (Form 1 to Form 4) applies to switchboards (IEC 61439-2), not busbar trunking. Busway uses IP rating and partial barriers for protection. iec 61439-6 pdf