NCCER Introduction To The National Electrical Code (26105-20) Practice Test

Overcurrent protection is addressed in Article 240 of the NEC. This part sets how to protect conductors and equipment from excessive current that can cause overheating and fires. It covers the selection and installation of overcurrent devices—fuses and circuit breakers—and the rules for sizing those devices to match the conductor ampacity and the equipment rating they protect. It also includes placement requirements for the devices and considerations like interrupting ratings for short-circuit conditions. In practice, you size the overcurrent device so it doesn't exceed what the conductor can safely carry, while still providing protection appropriate for the load. For context, other articles cover different topics: Article 100 provides definitions used across the NEC, Article 210 addresses branch circuits and related requirements, and Article 250 deals with grounding and bonding.