Texas Maintenance Electrician

Key Concepts

NEC arrangement and language (Article 90) - The Code is divided into the introduction and nine chapters; Chapters 1, 2, 3, and 4 apply generally, Chapters 5, 6, and 7 apply to special occupancies, special equipment, or other special conditions [90.3]. - Chapter 8 (communications systems) is not subject to Chapters 1 through 7 except where specifically referenced in Chapter 8; Chapter 9 consists of tables applicable as referenced [90.3]. - Mandatory rules use "shall" or "shall not" [90.5(A)]; permissive rules use "shall be permitted" or "shall not be required" [90.5(B)]. - The Code does not cover installations in ships, watercraft other than floating buildings, railway rolling stock, aircraft, or automotive vehicles other than mobile homes and recreational vehicles [90.2(D)]. - Metric (SI) units are the system of preference and SI shall appear first, with inch-pound units immediately following in parentheses [90.9(A), 90.9(B)].

Key Concepts

Service conductor sizing and ampacity - Overhead service conductors shall have an ampacity not less than the calculated load, and shall not be smaller than 8 AWG copper or 6 AWG aluminum or copper-clad aluminum (230.23(A), (B)). Exception: conductors supplying only a single branch circuit may be 12 AWG hard-drawn copper or equivalent. - Underground service conductors carry the same minimums — not smaller than 8 AWG copper or 6 AWG aluminum/copper-clad aluminum (230.31). - Service-entrance conductors supplying continuous and noncontinuous loads shall have an ampacity not less than the noncontinuous load plus 125 percent of the continuous load (230.42(A)(1)). Where the assembly is listed for operation at 100 percent of its rating, sizing at 100 percent of the sum of continuous plus noncontinuous load is permitted (230.42(A)(1), Exception No. 2). - Grounded service conductors shall not be less than the minimum size required by 250.24(D) (230.23(C), 230.31(C)).

Texas Maintenance Electrician · 3 questions (5% of exam)

Key Concepts

• Scope. Article 215 covers installation, overcurrent protection, minimum size, and ampacity of conductors for feeders not over 1000 volts ac or 1500 volts dc, nominal (215.1). Feeders above those values fall under Article 266 (215.1 Informational Note).
• Minimum rating and size. Feeder conductors shall have an ampacity not less than the larger of 215.4(A)(1) or 215.4(A)(2) and shall comply with 110.14(C).
• 215.4(A)(1): where a feeder supplies continuous loads or any combination of continuous and noncontinuous loads, ampacity shall be not less than the noncontinuous load plus 125 percent of the continuous load. Exception No. 1: if the assembly, including the feeder OCPDs, is listed for operation at 100 percent of its rating, ampacity may be the sum of continuous plus noncontinuous load. Exception No. 3: grounded conductors not connected to an OCPD may be sized at 100 percent of the…

Key Concepts

• Branch-circuit ratings. For other than individual branch circuits, the rating shall be 10, 15, 20, 30, 40, and 50 amperes (210.18). Where higher-ampacity conductors are used, the ampere rating or setting of the OCPD determines the circuit rating. Exception No. 2: branch circuits rated 10 amperes shall not supply receptacle outlets (also Table 210.24(1), footnote 2). Multioutlet circuits greater than 50 A are permitted only for nonlighting outlet loads where only qualified persons service the equipment (210.18, Exception No. 1).
• Minimum conductor ampacity. Branch-circuit conductors shall have an ampacity not less than the larger of: (1) noncontinuous load plus 125 percent of the continuous load per 310.14, and (2) the maximum load to be served after applying adjustment or correction factors per 310.15 (210.19(A)(1) and (A)(2)). Exception to (1): if the assembly including the OCPDs is listed for operation at 100 percent of its rating, continuous plus noncontinuous load is…

Key Concepts

Conductors of the same circuit. All conductors of the same circuit and, where used, the grounded conductor and all equipment grounding and bonding conductors shall be contained within the same raceway, conduit body, auxiliary gutter, cable tray, cablebus assembly, trench, cable, or cord unless otherwise permitted — 300.3(B) in the 2023 text; the verified questions note that "former Section 300.3(B) was renumbered to 300.5(B)." The permitted exception tested is paralleled installations — conductors may run in parallel per 310.10(G), with the same-raceway rule applying separately to each portion of the paralleled set (300.3(B)(1) / 300.5(B)(1)).

Limitations. Chapter 3 wiring methods are used for 1000 volts ac, 1500 volts dc, nominal, or less; they are permitted over those values only where specifically permitted elsewhere in the Code (300.2(A) / 300.4(A)). Single conductors in Table 310.4(1) are permitted only as part of a recognized Chapter 3 wiring method, except as separate overhead conductors per…

Key Concepts

Switches (Article 404) - The center of the grip of the operating handle of a switch or circuit breaker used as a switch, when in its highest position, shall be not more than 2.0 m (6 ft 7 in.) above the floor or working platform — 404.8(A).

Receptacles (Article 406) - Reconditioned receptacles, attachment plugs, cord connectors, and flanged surface devices shall not be permitted — 406.2. No exception exists for retesting. - Where no equipment grounding conductor exists in the receptacle enclosure, a non-grounding-type receptacle may be replaced with a GFCI-type receptacle marked "No Equipment Ground," and an EGC shall not be connected from that GFCI receptacle to any outlet supplied from it — 406.4(D)(2)(b). - Dwelling units: GFCI protection is required for receptacles installed within 1.8 m (6 ft) from the top inside edge of the bowl of a sink — 210.8(A)(8). - Other than dwelling units (e.g., commercial kitchens):…

Key Concepts

• Use table FLC, not nameplate, for most sizing. Per 430.6(A)(1), the values in Table 430.247, Table 430.248, Table 430.249, and Table 430.250 shall be used instead of the nameplate current to determine ampacity of conductors, current ratings of switches, and current ratings of branch-circuit short-circuit and ground-fault protection. Nameplate current is used for separate motor overload protection, and for motors built for low speeds (less than 1200 RPM), high torques, canned pumps, or multispeed motors (430.6(A)(2)).
• Single motor conductors: 430.22 — not less than 125 percent of the motor full-load current rating as determined by 430.6(A)(1). Special multipliers: wye-start, delta-run conductors between controller and motor 72 percent (430.22(C)); part-winding 62.5 percent (430.22(D)).
• Feeder conductors: 430.24 — not less than 125 percent of the full-load current of the highest rated motor plus the sum of the full-load currents of all other motors in the group. Per 430.17, the highest or…

Key Concepts

Damp/wet location enclosures. Panelboards in damp or wet locations shall be installed to comply with 312.2 (NEC 2023, 408.37). The same reference applies to enclosures for overcurrent devices (240.32) and to switchboards and switchgear (408.16). Surface-mounted switches or circuit breakers in wet locations must be in weatherproof enclosures complying with 312.2 (404.4(A), NEC 2023). Edition note: the NEC 2026 text in the SOURCE renumbers this reference — 408.37, 408.16 and 404.6(A) point to 312.4, and flush-mounted switches or circuit breakers require weatherproof covers (404.6(B)). Switches are not permitted within tub or shower spaces unless part of a listed tub or shower assembly (404.6(C)).

Key Concepts

Documentation. Areas designated as hazardous (classified) or determined to be unclassified shall be documented on an area classification drawing and other associated documentation, available to the AHJ and to those authorized to design, install, inspect, maintain, or operate the equipment — 500.4.

Class and Division definitions. - Class I = flammable gases, flammable liquid–produced vapors, or combustible liquid–produced vapors in air in quantities sufficient to produce explosive or ignitible mixtures — 500.5(B). Division 1 = ignitible concentrations can exist under normal operating conditions; or might exist frequently because of repair or maintenance operations or because of leakage; or breakdown/faulty operation might release ignitible concentrations and simultaneously fail electrical equipment — 500.5(B)(1). Division 2 = material normally confined in closed containers/systems, escaping only on accidental rupture or breakdown, or abnormal equipment operation; or ignitible concentrations normally prevented by positive mechanical ventilation; or adjacent to a Division 1 location — 500.5(B)(2). - Class II…