E2 Study Guide 2026
Everything you need to pass the E2 exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📋 E2 Exam Format at a Glance
📚 E2 Topics to Study (88)
✍️ Sample E2 Questions & Answers
1. A transformer nameplate lists an impedance of 5.75%. This value is primarily used to calculate:
Transformer impedance (%Z) is the key parameter for calculating available short-circuit current on the secondary side.
2. Per NEC 312.11, when shall a wiring enclosure (cabinet or cutout box) be secured to the wall or other supporting surface?
NEC 312.11 requires that all cabinets, cutout boxes, and meter socket enclosures be securely fastened in place.
3. A run of rigid PVC conduit passes through a building expansion joint. The inspector should verify the presence of:
NEC 352.44 requires an expansion fitting listed for PVC where the conduit crosses a structural expansion joint.
4. When installing an isolated power system, the maximum total length of the branch circuit conductors on the secondary side of the isolation transformer is:
NEC 517.160(A)(3) limits the length of secondary conductors of an isolated power system to 50 feet to minimize distributed capacitance that degrades isolation.
5. When sizing conductors for a feeder supplying several motors, NEC 430.24 requires the feeder ampacity to equal the largest motor FLC multiplied by 125% plus:
NEC 430.24 adds 125% of the largest motor FLC to the sum of all other motor full-load currents at 100%.
6. In a Class I, Zone 0 location per NEC Article 505, flammable concentrations of gases are present:
Zone 0 is the most hazardous classification under the Zone system, where flammable concentrations are present continuously or for long periods.