Texas Journeyman Lineman Electrician

Key Concepts

Purpose and scope (90.1, 90.2(A), 90.2(B)) - Article 90 covers use and application, arrangement, and enforcement of the Code; the expression of mandatory, permissive, and nonmandatory text; guidance on examination of equipment and wiring planning; and the use and expression of measurements (90.1). - The purpose of the Code is "the practical safeguarding of persons and property from hazards arising from the use of electricity." It is not intended as a design specification or an instruction manual for untrained persons (90.2(A)). - Compliance plus proper maintenance yields an installation "essentially free from hazard but not necessarily efficient, convenient, or adequate for good service or future expansion" (90.2(B)).

Installations covered / not covered (90.2(C), 90.2(D)) - Covered: public and private premises including buildings, structures, mobile homes, recreational vehicles, and floating buildings; yards, lots, parking lots, carnivals, industrial substations; shore power to ships and watercraft in marinas and boatyards; installations exporting power from vehicles to premises wiring (90.2(C)). - Not covered: installations in ships, watercraft other than floating buildings, railway rolling stock, aircraft, or…

Key Concepts

Scope and number of services - Article 230 covers service conductors and equipment for services not over 1000 volts ac or 1500 volts dc, nominal (230.1). - A building or structure shall be supplied by only one service unless permitted by 230.2(A) through (D): special conditions (fire pumps, emergency systems, legally required standby, optional standby, interconnected electric power production sources, multiple sources for enhanced reliability); special occupancies by special permission; capacity requirements in excess of 2000 amperes at a supply voltage of 1000 volts or less; or different voltages, frequencies, phases, or uses (230.2). - Where a building is supplied by more than one service, a permanent plaque or directory shall be installed at each service disconnect location (230.2(E)). - Service conductors supplying a building shall not pass through the interior of another building (230.3).

Key Concepts

• Minimum feeder ampacity. Feeder conductors shall have an ampacity not less than the larger of 215.2(A)(1) or (A)(2) and comply with 110.14(C). For continuous loads or any combination of continuous and noncontinuous loads, the minimum size shall have an ampacity not less than the noncontinuous load plus 125 percent of the continuous load [NEC 215.2(A)(1)]. Exception No. 1: if the assembly, including the overcurrent devices, is listed for operation at 100 percent of its rating, the ampacity may be the sum of continuous plus noncontinuous load. Exception No. 3: grounded conductors not connected to an overcurrent device may be sized at 100 percent of the load.
• Feeder overcurrent protection. The rating of the OCPD shall not be less than the noncontinuous load plus 125 percent of the continuous load, with the same 100 percent–rated assembly exception [NEC 215.3].
• Ampacity relative to service conductors. Feeder ampacity shall not be less than that of the service conductors where the feeder carries the total load supplied by service conductors of **55 amperes…

Key Concepts

Branch-circuit ratings (210.18). Branch circuits are rated by the maximum permitted ampere rating or setting of the overcurrent device. "The rating for other than individual branch circuits shall be 10, 15, 20, 30, 40, and 50 amperes." Where higher-ampacity conductors are used, the OCPD rating determines the circuit rating. Exception No. 1: multioutlet branch circuits greater than 50 amperes are permitted for nonlighting outlet loads where conditions of maintenance and supervision ensure only qualified persons service the equipment. Exception No. 2: 10-ampere branch circuits shall not supply receptacle outlets.

Minimum ampacity (210.19(A)). Conductors must have an ampacity not less than the larger of (1) noncontinuous load plus 125 percent of the continuous load in accordance with 310.14, and (2) the maximum load to be served after applying adjustment or correction factors per 310.15, and must comply with 110.14(C) for terminations. Exception to (1): if the assembly, including the OCPDs, is listed for operation at 100 percent of its rating, the conductors may be sized at continuous plus noncontinuous load per 110.14(C).

Key Concepts

Protection through and along framing members - Bored holes in joists, rafters, or wood members: the edge of the hole must be not less than 32 mm (1-1/4 in.) from the edges of the wood member. Where that distance can't be maintained, protect the cable/raceway with a steel plate(s) or bushing(s) at least 1.6 mm (1/16 in.) thick — NEC 300.4(A)(1) (renumbered 300.6(A)(1) in the 2026 text). - Exception No. 1: steel plates are not required to protect RMC, IMC, rigid PVC conduit, RTRC, or EMT — 300.4(A)(1). - Notches in wood: cable/raceway must be protected by a steel plate at least 1.6 mm (1/16 in.) thick, installed before the building finish is applied — 300.4(A)(2). - NM cable through punched/cut/drilled holes in metal members: protect with listed bushings or grommets securely fastened in the opening prior to installing the cable — 300.4(B)(1). - Cable or raceway run parallel to joists, rafters, studs, or furring strips: nearest outside surface must be not less than 32 mm (1-1/4 in.) from the nearest edge,…

Key Concepts

Scope (408.1). Article 408 covers switchboards, switchgear, and panelboards. It does not apply to equipment operating at over 1000 volts except where specifically referenced elsewhere in the Code.

Bus arrangement (408.3(E)(1)). AC phase arrangement on 3-phase buses shall be A, B, C from front to back, top to bottom, or left to right, as viewed from the front of the switchboard, switchgear, or panelboard. The B phase shall be the phase having the higher voltage to ground on 3-phase, 4-wire, delta-connected systems. Other busbar arrangements are permitted for additions to existing installations and shall be marked; an exception also permits equipment within the same switchboard, switchgear, or panelboard as the meter on 3-phase, 4-wire, delta-connected systems to have the same phase configuration as the metering equipment. DC ungrounded buses may be in any order but must be field marked as to polarity, grounding system, and nominal voltage (408.3(E)(2)).

Key Concepts

Motor circuit conductors (Article 430, Part II) - Branch-circuit conductors for a single motor must have an ampacity of at least 125 percent of the motor full-load current — NEC 430.22(A). - Feeder conductors supplying several motors: 125 percent of the largest motor's FLC plus the sum of the full-load currents of the other motors — NEC 430.24. - Conductor size is selected from the ampacity tables in 310.15 or calculated per 310.14(B); where flexible cord is used, size is selected per 400.5 — NEC 430.6. - For general motor applications, the table values (Table 430.247 through Table 430.250) are used instead of the nameplate current to determine conductor ampacity, switch ratings, and branch-circuit short-circuit and ground-fault protection — 430.6(A)(1). Nameplate current is used for separate motor overload protection — 430.6(A)(2).

Overload protection (Part III) - Motor overload protection is set at 115 percent of FLC for standard motors, and up to 125 percent for motors with a service factor ≥ 1.15 or temperature rise ≤ 40°C — NEC 430.32(A)(1).

Texas Journeyman Lineman Electrician · 6 questions (15%)

Key Concepts

Service disconnecting means — number and arrangement - Each service shall have only one service disconnect unless the requirements of 230.71(B) are met (230.71). - Two to six service disconnects are permitted, but they must be in separate enclosures with a single service disconnect in each enclosure, separate switchboard vertical sections (with barriers), separate switchgear or transfer switch compartments, or separate metering center compartments (230.71(B)). - Disconnects installed as part of listed equipment used solely for power monitoring, SPD disconnection, ground-fault protection control circuits, or control circuits for power-operable service disconnects are not counted among the permitted service disconnects (230.71(A)). - The two to six disconnects shall be grouped and each marked to indicate the load served (230.72(A)).