Electronic test set embodiments and related methods are provided that can include a variety of safety components and/or processes which permit expandable or scalable automated testing of different types of equipment with or without installed sensitive, dangerous, vulnerable or expendable equipment. Embodiments can programmably or interface share measuring systems using expandable programmable interface systems that can scalably test a large number of components or electrical channels or bus lines. Embodiments can include multiple circuit board slot connectors adapted to receive programmable relay circuit cards that can selectively couple individual pins on ETS interface structures (e.g., cable connectors) to selected test equipment. Programmable relay circuit cards can be added to the ETS based on how many channels or bus connections are needed to interface with a system under test.