PC Cheat Sheet 2026

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

1. Per NEC Table 220.54, what is the demand factor for household electric dryers when 5 dryers are supplied from the same feeder? → 80%
2. A squirrel cage induction motor is classified as what type of motor? → AC induction motor
3. What is the purpose of a ground wire in electrical installations? → To provide a safe path for electrical faults to the ground.
4. What is the apparent power (in kVA) of a three-phase motor with a line voltage of 480V, drawing a line current of 60A? → 50.0 kVA
5. Per NEC 230.24(B), what is the minimum clearance required for service drop conductors above public streets subject to truck traffic? → 18 feet
6. What is the minimum ampacity required for branch circuit conductors supplying a single continuous-duty motor? → 125% of motor FLA
7. Which NEC article covers motors, motor circuits, and controllers? → Article 430
8. Which agency oversees and enforces electrical code compliance in the U.S.? → The Occupational Safety and Health Administration (OSHA).
9. What is the minimum horsepower rating required for a motor disconnecting means per NEC 430.110? → Equal to the motor's HP rating
10. Why must electrical codes be followed during installation? → To ensure safety, compliance, and system reliability.
11. What is the primary purpose of taps on a transformer primary winding? → To adjust secondary voltage output when primary voltage varies from nominal
12. What is the significance of grounding in electrical safety? → It prevents electric shocks and fires by directing excess electricity to the earth.
13. Which device provides both overload protection and short-circuit protection for a motor in a single assembly? → Combination motor controller
14. Which NEC article governs air conditioning and refrigeration equipment containing hermetically sealed motor-compressors? → Article 440
15. Per NEC 450.3, when a transformer has primary overcurrent protection set at no more than 125% of rated current, secondary overcurrent protection: → May be omitted if primary protection does not exceed 125% of primary rated current
16. In a typical commercial distribution system, primary distribution feeders in urban areas operate at what voltage range? → 4,160V to 15,000V
17. Why is it important to correctly size electrical wiring? → To prevent overheating and potential hazards.
18. Why is it important to adhere to electrical codes during installation? → To ensure safety, reliability, and regulatory compliance.
19. What is a load calculation in electrical system design? → A process to determine the electrical demand and ensure the system can handle it.
20. Which NEC article covers service conductors and equipment for electrical services? → Article 230
21. A motor has a nameplate FLA of 20A and a service factor of 1.15. What is the maximum overload protection rating per NEC 430.32? → 26A (130%)
22. A delta-wye transformer configuration is commonly used in electrical distribution primarily because it: → Provides voltage transformation and establishes a neutral point on the secondary
23. What is the main purpose of electrical codes in residential areas? → To ensure electrical systems are safe, reliable, and code-compliant.
24. Why is the circuit breaker used in electrical installations? → To disconnect the circuit in case of overload or fault.
25. What is the primary function of a transformer in an electrical circuit? → To change the voltage level of alternating current (AC).
26. Per NEC 430.102, where must the motor disconnecting means be located? → Within sight of the motor and within 50 feet
27. What is the unit of measurement for electrical resistance? → Ohms.
28. Which transformer cooling designation indicates an oil-immersed, forced-oil-cooled, forced-air-cooled unit? → OFAF
29. What is the main difference between Class I, II, and III locations in electrical code? → They classify areas based on the potential for hazardous conditions.
30. For a 200-ampere residential service, what is the minimum copper conductor size per NEC Table 310.12? → 3/0 AWG