CME Cheat Sheet 2026

The 30 highest-yield CME facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. Which of the following is explicitly prohibited as a grounding electrode per NEC 250.52(B)? → Metal underground gas piping system
2. When grounding an indoor separately derived AC system, such as a dry-type transformer, which of the following must be used as the grounding electrode? → The building or structure grounding electrode system.
3. A motor nameplate shows: 460V, 3Ø, 60Hz, 25HP, 1.15 SF. What is the maximum continuous current the motor can draw without damaging the insulation? → FLA multiplied by the 1.15 service factor
4. What is the primary function of a motor overload relay in a motor branch circuit? → Protect the motor windings from sustained overcurrent due to overloading or locked rotor
5. Which harmonic order is typically the most problematic in three-phase systems powered by six-pulse VFDs? → 5th and 7th
6. What is the primary purpose of electrical codes and standards? → To ensure safety, reliability, and efficiency in electrical installations.
7. What is the role of circuit protection in electrical systems design? → To prevent damage, fire, and ensure safety.
8. Under ASHRAE 90.1, which lighting control strategy is REQUIRED for commercial spaces greater than 5,000 sq ft? → Automatic shutoff controls
9. Per NEC Table 250.66, what is the minimum size copper grounding electrode conductor (GEC) for a service with 3/0 AWG copper service-entrance conductors? → 4 AWG
10. What is the primary function of the equipment grounding conductor (EGC) in a branch circuit? → To provide a low-impedance fault current path that enables overcurrent device operation
11. Per NEC 250.119, equipment grounding conductors must be identified by which of the following? → Green insulation, green with yellow stripes, or bare conductor
12. What is the role of the National Electrical Code (NEC) in electrical installations? → To ensure that electrical systems are installed safely and in compliance with regulations.
13. What is the role of circuit testing during troubleshooting? → To identify faults and ensure safe system functionality.
14. Per NEC 430.102(B), what is required at the location where a motor disconnect is not within sight of the motor controller? → The disconnect must be lockable in the open position
15. How can electrical systems be designed to minimize hazards? → By incorporating grounding, circuit protection, and safety standards.
16. Why is it important to use the proper tools for electrical troubleshooting? → To ensure accurate diagnostics and safety.
17. Which device is most effective for mitigating voltage sags caused by motor starting on a distribution system? → Static VAR compensator (SVC)
18. Per NEC 240.4(D)(3), what is the maximum overcurrent protection permitted for a 10 AWG copper branch-circuit conductor? → 30A
19. What is the role of personal protective equipment (PPE) in electrical work? → To protect workers from electrical hazards and injuries.
20. What is the purpose of grounding in electrical systems? → To ensure safe discharge of faults and prevent electrical shock.
21. Per NEC 501.10(A), what wiring methods are permitted in Class I, Division 1 hazardous locations? → Threaded rigid metal conduit (RMC) or threaded steel intermediate metal conduit (IMC)
22. In a hospital's essential electrical system (EES), which of the following loads is required to be connected to the critical branch? → Task illumination and select receptacles in the intensive care unit (ICU).
23. How does preventive maintenance contribute to electrical system longevity? → It minimizes wear and tear, ensuring safe and reliable performance.
24. When establishing an electrically safe work condition, which of the following steps is performed immediately AFTER locking and tagging the disconnecting means? → Test the circuit with a properly rated voltmeter to verify the absence of voltage.
25. What is the acceptable range of Total Harmonic Distortion (THD) for voltage at a point of common coupling per IEEE 519? → Less than 5%
26. What is the role of documentation in troubleshooting electrical systems? → It provides valuable information for future troubleshooting and system improvements.
27. What is the minimum burial depth for a ground ring below the surface of the earth per NEC 250.52(A)(4)? → 30 inches
28. How do lockout/tagout procedures contribute to electrical safety? → They prevent accidental activation of electrical systems during maintenance.
29. Per NEC Article 250, what is the primary purpose of bonding metal parts in an electrical system? → To establish electrical continuity and conductivity between metal parts
30. Per NEC 210.19(A)(1), branch circuit conductors serving continuous loads must be sized to what percentage of the continuous load current? → 125%