A cartridge fuse which does not have an IC rating marked on its surface shall be considered as having an IC rating of ______.

The correct answer is based on the standard practices related to fuse ratings in the context of electrical installations. In situations where a cartridge fuse does not have an interrupting capacity (IC) rating marked on its surface, it is assumed to have a default IC rating of 10,000 amps. This assumption is rooted in industry standards that help ensure safety and effectiveness in electrical systems.

The IC rating indicates the fuse's ability to safely interrupt fault currents without causing damage or posing hazards. Therefore, in the absence of a specification, using the 10,000-amp rating provides a reliable guideline for determining the fuse's performance in safeguarding the circuit. This uniformity helps electricians and engineers make informed decisions when selecting appropriate protective devices for their systems, ensuring adequate protection against overcurrent conditions.