Journeyman/Master Electrician License Exam Low-Voltage, Communications, and Code Application Syllabus

Low-Voltage, Communications, and Code Application syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for Low-Voltage, Communications, and Code Application in Journeyman/Master Electrician License Exam, not a summary of it.

1. 1

   Class 1, 2, and 3 and Limited-Energy Circuits

   3 topics

   • Power-Limited Circuits (Article 725)
     • Class 2 and Class 3 power source limits
     • Separation from power conductors
   • Fire Alarm Systems (Article 760)
     • Power-limited vs. non-power-limited circuits
     • Survivability and cable types
   • Communications and Coaxial Systems (Articles 800, 805, 820)
     • Primary protector and grounding/bonding
     • Cable listing markings (CMP, CMR, CM)
2. 2

   Exam Calculation Strategy

   3 topics

   • Time Management for Open-Book Exams
     • Tabbing and highlighting the code book
     • Locating tables and articles quickly
   • Common Calculation Question Types
     • Multi-step service load problems
     • Conduit fill and box fill combination problems
   • Unit Conversions and Formula Recall
     • Horsepower, kVA, and VA conversions
     • Memorized constants (1.732, 1000, K values)
3. 3

   Trade Practices, Safety, and Licensing Law

   3 topics

   • OSHA and NFPA 70E Safety
     • Lockout/tagout and approach boundaries
     • Personal protective equipment and arc-flash categories
   • Permits, Inspections, and the AHJ
     • Role of the Authority Having Jurisdiction
     • Plan review and rough-in vs. final inspection
   • State and Local Licensing Rules
     • Journeyman vs. master scope of work and supervision
     • Continuing education and license renewal

Low-Voltage, Communications, and Code Application flashcards for Journeyman/Master Electrician License Exam

25 of 49 cards from the Low-Voltage, Communications, and Code Application deck — real questions with worked answers.

1. Under NEC Article 725, what is the difference between a Class 1, Class 2, and Class 3 circuit?

   Class 1 circuits are power-limited to 30 V and 1000 VA or remote-control/signaling up to 600 V (not power-limited as to current). Class 2 and Class 3 are power-limited circuits whose power source is limited by listed equipment; Class 2 limits both voltage and power for shock/fire safety, while Class 3 allows higher voltage (up to 150 V) with added protection against shock because more energy is permitted.

2. What NEC article covers power-limited and Class 1, Class 2, and Class 3 remote-control, signaling, and power-limited circuits?

   Article 725.

3. For a Class 2 circuit power source, what are the typical maximum voltage and power limits (dry location, continuous AC source)?

   A Class 2 source is generally limited to a maximum of 30 V and the power is limited so that the source cannot exceed roughly 100 VA (for a 30 V source, current limit around 5 A after considering overcurrent protection); these limits make Class 2 inherently safe from a fire and shock standpoint.

4. In Article 725, why can Class 2 and Class 3 conductors generally NOT be placed in the same cable or raceway as Class 1 or power/light circuits?

   Because Class 2 and Class 3 circuits are power-limited and must be kept separated from non-power-limited (Class 1, electric light, power) conductors to prevent a higher-energy circuit from imposing dangerous voltage/energy onto the power-limited wiring. Separation (typically a barrier or a minimum spacing) is required unless specific exceptions are met.

5. What do the cable type abbreviations CL2, CL3, CL2P, CL2R, and CL2X designate in Article 725?

   CL2/CL3 are Class 2/Class 3 cables. The suffixes indicate use rating: 'P' = plenum (highest fire rating), 'R' = riser (vertical runs between floors), 'X' = limited use (dwellings/raceways), and no suffix = general-purpose. Higher-rated cables may substitute for lower-rated ones (P > R > general > X).

6. What NEC article governs the installation of fire alarm systems?

   Article 760.

7. In Article 760, what is the difference between a power-limited (PLFA) and non-power-limited (NPLFA) fire alarm circuit?

   NPLFA circuits are not power-limited and follow Class 1 wiring rules (e.g., max 600 V), requiring more robust wiring methods. PLFA circuits are supplied by a listed power-limited source and follow Class 2/Class 3-style rules with smaller conductors and the FPL cable family.

8. What cable type designations are used for power-limited fire alarm circuits in Article 760?

   The FPL family: FPL (general purpose), FPLR (riser), and FPLP (plenum). As with other cables, plenum-rated may substitute for riser, and riser for general purpose.

9. In a fire alarm circuit, what color is conventionally required (and often mandated by listing) for the cable jacket to identify it?

   Power-limited fire alarm cable is conventionally identified with a red jacket, though the NEC itself focuses on marking/listing; red is the industry-standard color for fire alarm wiring.

10. What NEC article covers communications circuits (telephone and similar), including station wiring?

    Article 800 (with Article 805 historically covering communications circuits; in modern NEC, Article 800 is the general communications wiring article).

11. What NEC article specifically covers coaxial cable distribution (community antenna television and radio, CATV)?

    Article 820.

12. What do the communications cable types CM, CMR, CMP, CMX, and CMG indicate?

    CM = communications general purpose, CMR = riser, CMP = plenum (highest fire rating), CMX = limited use (dwelling/raceway), CMG = general purpose (group rating). Substitution allows higher-rated cables in place of lower-rated ones: CMP > CMR > CMG/CM > CMX.

13. What are the coaxial cable type designations under Article 820 and their meanings?

    CATV = general purpose, CATVR = riser, CATVP = plenum, and CATVX = limited use. The plenum type has the highest flame/smoke rating and can substitute downward.

14. Under Article 820, why and how must a coaxial cable shield be grounded (bonded)?

    The outer conductive shield of coax must be bonded/grounded at the building entrance (primary protector or grounding block) to the building grounding electrode system, using a bonding conductor no smaller than 14 AWG, to safely conduct fault and lightning energy and equalize potential.

15. What is the general grounding-conductor maximum length goal for communications/coax bonding at the building entrance?

    The primary protector/grounding conductor should be as short as practicable; the NEC commonly requires the grounding conductor run to be limited to about 20 ft for one- and two-family dwellings to minimize impedance during a surge.

16. What is a 'primary protector' in communications (Article 800) wiring and when is it required?

    A primary protector is a listed surge/overvoltage protective device installed where communications conductors enter a building; it is required when the cable could be exposed to lightning, accidental contact with power conductors over 300 V, or power induction. It limits voltage to ground and protects equipment and people.

17. For an open-book trades exam, what is the recommended first time-management step before answering questions?

    Budget your time by dividing total exam minutes by the number of questions to get an average pace (e.g., 4 hours / 80 questions = 3 minutes each), then answer easy questions first and flag/skip hard look-up questions to return to later.

18. On an open-book NEC exam, what tabbing/indexing strategy saves the most time?

    Pre-tab your code book by article and major table, and rely heavily on the NEC Index and Table of Contents; practice finding articles by keyword so you can locate references in seconds rather than reading sequentially.

19. If a single open-book exam question is taking too long to look up, what is the best time-management decision?

    Mark/flag it, make your best educated guess so no answer is blank (if there is no penalty for guessing), and move on; return to flagged questions only after completing all the ones you can answer quickly.

20. What is the formula for electrical power in a DC or resistive circuit, and what are common exam variants?

    $P = V \times I$. Common variants from Ohm's law substitution are $P = I^{2}R$ and $P = \frac{V^{2}}{R}$.

21. State Ohm's Law and its two algebraic rearrangements.

    $V = I \times R$, rearranged as $I = \frac{V}{R}$ and $R = \frac{V}{I}$, where $V$ is volts, $I$ is amperes, and $R$ is ohms.

22. What is the formula for single-phase power including power factor, as used on the license exam?

    $P = V \times I \times PF$, where $PF$ is the power factor (between 0 and 1). For apparent power, $S = V \times I$ in volt-amperes.

23. What is the three-phase power formula tested on the journeyman/master exam?

    $P = \sqrt{3} \times V_{L} \times I_{L} \times PF$, where $V_{L}$ and $I_{L}$ are line voltage and line current, and $\sqrt{3} \approx 1.732$.

24. How do you calculate the full-load current of a single-phase motor or load given kVA?

    $I = \frac{VA}{V} = \frac{kVA \times 1000}{V}$. For example, a 10 kVA single-phase load at 240 V draws $\frac{10000}{240} \approx 41.7$ A.

25. How do you calculate line current for a three-phase load given kVA and line voltage?

    $I_{L} = \frac{kVA \times 1000}{\sqrt{3} \times V_{L}}$. For example, 30 kVA at 480 V: $\frac{30000}{1.732 \times 480} \approx 36.1$ A.

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