Final answer:
The question is about certain types of fuseholders that are now considered obsolete and unsafe in electrical systems, likely due to inadequate safety features according to current standards.
Step-by-step explanation:
The subject of the question refers to types of fuseholders that are no longer considered safe for use in electrical systems. While the question does not specify which particular type, it implies that certain older fuseholder designs are now obsolete due to safety concerns. These concerns may arise from issues such as the lack of proper insulation, the potential for overloading, or the use of materials that do not meet current safety standards. In modern electrical practices, it is crucial to adhere to updated safety guidelines that include the use of fuseholders designed to prevent electrical fires and other hazards.