Which of the following is not an overcurrent protective device category?

• A. Equipment Overcurrent Protective Devices
• B. Application-Limited OCPDs
• C. Branch-Circuit Overcurrent Protective Devices
• D. Supplementary Overcurrent Protective Devices

Answer: (C)

Understanding how protective devices are categorized helps you see why that option is the one that isn’t a category. In standards, overcurrent protective devices (OCPDs) are grouped into specific categories that describe the purpose and characteristics of the protection: equipment overcurrent protective devices protect equipment, application-limited OCPDs limit protection based on the particular application, and supplementary overcurrent protective devices provide additional protection to improve coordination with the main device. Branch-circuit overcurrent protective devices, by contrast, describes where the protection is applied (the branch circuit) rather than a distinct category defined in the standards. So it isn’t listed as a separate OCPD category, even though a branch circuit will be protected by an OCPD. The other three options refer to actual, named categories of OCPDs, which is why they fit as categories.