North Carolina Electrical Contractor - Fire Alarm/Low Voltage (SP-FA/LV)

NEC 2020 — Article 250 (Grounding and Bonding) and Article 200 (Use and Identification of Grounded Conductors)

Key Concepts

The earth is never a fault path. Per NEC 250.4(A)(5), "The earth shall not be considered as an effective ground-fault current path." The effective ground-fault current path must be a low-impedance circuit capable of safely carrying the maximum ground-fault current likely to be imposed on it from any point on the wiring system to the electrical supply source. The parallel statement for ungrounded systems, 250.4(B)(4), says "The earth shall not be considered as an effective fault-current path."

Objectionable current (250.6(B)). If multiple grounding connections result in objectionable current and the requirements of 250.4(A)(5) or (B)(4) are met, permitted alterations are: (1) discontinue one or more but not all of such grounding connections; (2) change the locations of the grounding connections; (3) interrupt the continuity of the conductor or conductive path causing the objectionable current; (4) take other suitable remedial and approved action. Per 250.6(C), temporary currents from abnormal conditions such as ground faults are not classified as objectionable current.

Key Concepts

Cable securing, support and bending - Type AC: bends made so the cable is not damaged; radius of the inner edge not less than five times the diameter of the cable — 320.24. Secure within 300 mm (12 in.) of every outlet box, junction box, cabinet, or fitting and at intervals not exceeding 1.4 m (4½ ft) — 320.30(B). - Type MC with interlocked-type armor or corrugated sheath: bending radius not less than seven times the external diameter of the metallic sheath — 330.24(B); secured at intervals not exceeding 1.8 m (6 ft) — 330.30(B). - Type NM/NMC: bending radius not less than five times the diameter — 334.24; supported and secured at intervals not exceeding 1.4 m (4½ ft) and within 300 mm (12 in.) of every cable entry into enclosures — 334.30. - Type MI: supported/secured at intervals not exceeding 1.8 m (6 ft) — 332.30. Where MI terminates, an end seal fitting shall be installed immediately after stripping to prevent moisture entering the insulation — 332.40(B).

NC Electrical Contractor, Fire Alarm/Low Voltage (SP-FA/LV) — 3 questions (6%) All rules below come from NEC 2020, Article 314.

Key Concepts

General information

• Round boxes shall not be used where conduits or connectors requiring the use of locknuts or bushings are to be connected to the side of the box — 314.2.
• Nonmetallic boxes are permitted only with open wiring on insulators, concealed knob-and-tube wiring, cabled wiring methods with entirely nonmetallic sheaths, flexible cords, and nonmetallic raceways — 314.3. Exception No. 1: where internal bonding means are provided between all entries, nonmetallic boxes are permitted with metal raceways or metal-armored cables. Exception No. 2 covers integral bonding means with a provision for attaching an equipment bonding jumper inside the box between all threaded entries in nonmetallic boxes listed for the purpose.
• Metal boxes shall be grounded and bonded per Parts I, IV, V, VI, VII, and X of Article 250, except as permitted in 250.112(I) — 314.4.
• Damp or wet locations: boxes, conduit bodies, outlet box hoods, and fittings installed in wet locations shall be listed for wet locations. Approved field-installed drainage openings shall be **not smaller than 3 mm (⅛ in.) and not…

Key Concepts

Scope and what Article 725 covers. Article 725 covers remote-control, signaling, and power-limited circuits that are not an integral part of a device or of utilization equipment (725.1). Only those sections of Article 300 referenced in Article 725 apply to Class 1, Class 2, and Class 3 circuits (725.3).

Motor control circuits. Motor control circuits must also comply with Article 430, Part VI, where tapped from the load side of the motor branch-circuit protective device(s) as specified in 430.72(A) (725.3(F)).

Safety-control equipment. Remote-control circuits for safety-control equipment shall be classified as Class 1 if the failure of the equipment to operate introduces a direct fire or life hazard (725.31(A)). Room thermostats, water temperature regulating devices, and similar controls used with electrically controlled household heating and air conditioning shall not be considered safety-control equipment (725.31(A)). Where damage to those remote-control circuits would introduce such a hazard, all conductors shall be installed in rigid metal conduit, intermediate metal conduit, rigid nonmetallic conduit, electrical metallic tubing, Type MI cable, or Type MC cable, or be otherwise suitably protected from physical damage (725.31(B)).

Key Concepts

• Scope. Article 310 covers general requirements for conductors rated up to and including 2000 volts — type designations, insulations, markings, mechanical strengths, ampacity ratings and uses (NEC 2020, 310.1).
• Minimum conductor size. For voltage ratings up to and including 2000 volts, the minimum size is 14 AWG copper or 12 AWG aluminum or copper-clad aluminum, except as permitted elsewhere in the Code (310.3(A)).
• Conductor material. Solid aluminum conductors 8, 10, and 12 AWG shall be made of an AA-8000 series electrical grade aluminum alloy. Stranded aluminum 8 AWG through 1000 kcmil marked RHH, RHW, XHHW, THW, THHW, THWN, THHN, SE Style U and SE Style R shall also be AA-8000 series (310.3(B)).
• Stranding. Where installed in raceways, conductors 8 AWG and larger shall be stranded, unless specifically permitted or required elsewhere in the Code to be solid (310.3(C)).
• Surface markings. The AWG size or circular mil area shall be repeated at intervals not exceeding 610 mm (24 in.); all other markings at intervals not exceeding 1.0 m (40 in.) (310.8(B)(1)).
• Parallel conductors. Aluminum, copper-clad aluminum, or copper conductors for each phase, polarity, neutral, or grounded circuit may be connected in parallel…

Exam: North Carolina Electrical Contractor – Fire Alarm/Low Voltage (SP-FA/LV) · 6 questions (12%)

Key Concepts

Code arrangement and enforceability (Article 90) - Chapters 1, 2, 3, and 4 apply generally; Chapters 5, 6, and 7 apply to special occupancies, special equipment, or other special conditions and may supplement or modify the requirements in Chapters 1 through 7. Chapter 8 covers communications systems and is not subject to the requirements of Chapters 1 through 7 except where the requirements are specifically referenced in Chapter 8. Chapter 9 consists of tables applicable as referenced (NEC 2020, Section 90.3). - Mandatory rules are those that identify actions specifically required or prohibited, characterized by the terms shall or shall not (90.5(A)). Permissive rules use shall be permitted or shall not be required (90.5(B)). - Explanatory material, such as informational notes, is informational only and not enforceable as requirements of the Code (90.5(C)). Informative annexes are likewise not part of the enforceable requirements (90.5(D)). - Not covered by the Code: installations in ships, watercraft other than floating buildings, railway rolling stock, aircraft, or automotive vehicles other than mobile homes and recreational vehicles (90.2(B)(1)). - SI units appear first, with inch-pound units immediately following…

Key Concepts

Board structure and authority - The Board comprises one member from the NC Department of Insurance designated by the Commissioner of Insurance, one representative of the NC Association of Electrical Contractors, and five members appointed by the Governor — G.S. 87-39(a). Members serve staggered seven-year terms and may not serve consecutive complete terms — G.S. 87-39(b), (c). - Applicants for certification as a qualified individual must be at least 18 years of age — G.S. 87-42.

License classifications and project limits - Limited: a single project of a value not in excess of $100,000 and equipment or installation in the contract rated at not more than 1,000 volts — G.S. 87-43.3(a)(1). Intermediate's single-project limit is $200,000 — G.S. 87-43.3(a)(2). - Single-family detached residential dwelling license: single-project value shall not exceed the maximum established for a limited licensee — G.S. 87-43.4.