Continuation of the NCCER Level 3 electrical curriculum. This course explains how to size and select circuit breakers and fuses for various applications. Covers short circuit calculations and troubleshooting, discusses switchboards and switchgear, including installation, grounding, and maintenance requirements, covers ground fault relay testing. Describes the construction, operation, and applications of various transformers, covers transformer connections and grounding requirements. Covers the components, installation considerations, and NEC® requirements for commercial services.