ICC F17 Journeyman Electrician Exam (2014 NEC)

Key Concepts

Article 100 definitions (tested directly). - Approved = "acceptable to the authority having jurisdiction." (Article 100) - In Sight From (Within Sight From) = visible and not more than 15 m (50 ft) distant from the other equipment — both conditions must be met. - Continuous Load = a load where the maximum current is expected to continue for 3 hours or more. - Dwelling, Multifamily = a building containing three or more dwelling units (two units = two-family). - Copper-Clad Aluminum Conductors = copper metallurgically bonded to an aluminum core, copper forming a minimum of 10 percent of the cross-sectional area. - Overcurrent Protective Device, Branch-Circuit = interrupting rating not less than 5000 amperes. - Surge-Protective Device: Type 1 = permanently connected, between the service transformer secondary and the line side of the service disconnect overcurrent device; Type 2 = load side; Type 3 = point-of-utilization; Type 4 = component. -…

ICC F17 Journeyman Electrician Exam (2014 NEC)

Key Concepts

Grounding electrodes (250.52(A)) - Concrete-encased electrode: at least 20 ft of 1/2 in. rebar or 4 AWG bare copper; metallic components encased by at least 2 in. of concrete, in the portion of the foundation/footing in direct contact with earth — 250.52(A)(3). - Ground ring: at least 20 ft of bare copper not smaller than 2 AWG — 250.52(A)(4). - Pipe/conduit electrode: not smaller than trade size 3/4 — 250.52(A)(5)(a). Rod-type of stainless steel or copper/zinc-coated steel: at least 5/8 in. diameter, unless listed — 250.52(A)(5)(b).

Electrode installation (250.53) - A single rod, pipe, or plate electrode must be supplemented by an additional electrode; the Exception removes that requirement if the single electrode has a resistance to earth of 25 ohms or less — 250.53(A)(2) Exception. - Plate electrodes: installed not less than 30 in. below the surface of the earth — 250.53(H). Ground ring:…

2014 NEC

Key Concepts

Minimum feeder conductor size (215.2(A)(1)(a)). Where a feeder supplies continuous loads or any combination of continuous and noncontinuous loads, the minimum feeder conductor size shall have an allowable ampacity not less than the noncontinuous load plus 125 percent of the continuous load. Under 215.2(A)(1)(b), conductors must also be not less than the maximum load served after adjustment/correction factors — size to the larger of (a) or (b).

Exception No. 1 to 215.2(A)(1): If the assembly, including the overcurrent devices protecting the feeder(s), is listed for operation at 100 percent of its rating, the allowable ampacity is permitted to be not less than the simple sum of continuous plus noncontinuous load.

Overcurrent protection (215.3). Same rule for the device: rating not less than the noncontinuous load plus 125 percent of the continuous load (Exception No. 1 for 100-percent-rated assemblies).

Key Concepts

Branch-circuit ratings and loads - For other than individual branch circuits, ratings are 15, 20, 30, 40, and 50 amperes (210.3). - Ranges rated 8-3/4 kW or more: minimum branch-circuit rating 40 amperes (210.19(A)(3)). Where the demand is taken from Column C of Table 220.55, the 3-wire neutral may be smaller than the ungrounded conductors but must be not less than 70 percent of the circuit rating and not smaller than 10 AWG (210.19(A)(3), Exception No. 2). - Heavy-duty lampholders (circuits over 20 A): not less than 660 watts if admedium type, not less than 750 watts if any other type (210.21(A)). - On a multiple-outlet circuit also supplying lighting or cord-and-plug equipment not fastened in place, utilization equipment fastened in place (other than luminaires) shall not exceed 50 percent of the circuit rating (210.23(A)(2)). - Show windows: one 125-volt, 15- or 20-ampere receptacle within 450 mm (18 in.) of the top…

Key Concepts

Rigid PVC Conduit (Article 352) - Securely fasten within 900 mm (3 ft) of each outlet box, junction box, device box, conduit body, or other conduit termination, unless listed for other spacings — 352.30(A). - Expansion fittings required where the length change per Table 352.44 is expected to be 6 mm (1/4 in.) or greater in a straight run between securely mounted items — 352.44. - Not permitted where ambient temperatures exceed 50°C (122°F) unless listed otherwise — 352.12(D). Not permitted in theaters and similar locations except as provided in 518.4 and 520.5 — 352.12(E). Not permitted where subject to physical damage unless identified for such use — 352.12(C); Schedule 80 is identified for areas of physical damage per the Informational Note to 352.10(F). - Field bends made only with identified bending equipment; centerline radius not less than Table 2, Chapter 9 — 352.24. Not more than the equivalent of four quarter…

Key Concepts

Luminaires (Article 410) - A luminaire weighing more than 3 kg (6 lb) or exceeding 400 mm (16 in.) in any dimension shall not be supported by the screw shell of a lampholder — 410.30(A). - No cord-connected luminaire, chain/cord-suspended luminaire, lighting track, pendant, or paddle fan in the zone 900 mm (3 ft) horizontally and 2.5 m (8 ft) vertically from the top of a bathtub rim or shower stall threshold — 410.10(D). - Clothes closets: 300 mm (12 in.) clearance to closet storage space for surface-mounted incandescent or LED luminaires with a completely enclosed light source on the wall above the door or on the ceiling; 150 mm (6 in.) for surface-mounted fluorescent and for recessed types — 410.16(C). - Combustible wall/ceiling finish exposed between the edge of a canopy or pan and an outlet box having a surface area of 1160 mm² (180 in.²) or more shall be covered…

Key Concepts

Controllers — what may serve as one - A general-use switch rated not less than twice the motor full-load current is permitted as the controller for stationary motors rated 2 hp or less and 300 volts or less — 430.83(C). The same thresholds appear in 430.109(C) for the disconnecting means. - An attachment plug and receptacle or cord connector is permitted as the controller for a portable motor rated 1/3 hp or less — 430.81(B). (The 1/8 hp figure in 430.81(A) is for stationary motors normally left running, where the branch-circuit disconnecting means may serve as the controller.) - A general-use or isolating switch plainly marked "Do not operate under load" is permitted as the disconnecting means for stationary motors rated more than 40 hp dc or 100 hp ac — 430.109(E). - Motor-starting rheostats for dc motors on a constant voltage supply must have automatic devices that interrupt the supply **before…

Key Concepts

Which current to use. For general motor applications, use the table values (Table 430.247–430.250) — not the nameplate — to size conductors, switches, and branch-circuit short-circuit and ground-fault (SCGF) protection [430.6(A)(1)]. Separate overload protection is based on the motor nameplate current rating [430.6(A)(2)].

Branch-circuit conductors. Not less than 125% of motor FLC [430.22(A)]. For a part-winding connected motor, conductors between controller and motor: not less than 62.5% of FLC (50% × 1.25) [430.22(D)]; wye-start, delta-run is 72% [430.22(C)].

Feeder conductors. 125% of the FLC of the highest rated motor plus the sum of the FLCs of all other motors in the group (plus non-motor loads at 100/125% as applicable) [430.24].

Branch-circuit SCGF protection. Maximum percentages come from Table 430.52(C)(1) — for single-phase, AC polyphase (other than wound rotor), squirrel cage and synchronous motors: inverse time breaker 250%, nontime-delay fuse 300%, dual-element fuse 175%, instantaneous trip breaker 800% (1100% for Design B energy-efficient).…

Key Concepts

Class III locations (Article 503) - Surface temperature limits: 165°C (329°F) for equipment not subject to overloading and 120°C (248°F) for equipment such as motors or power transformers that may be overloaded — 503.5. Carbonized or excessively dry organic material is highly susceptible to spontaneous ignition. - Zone equipment: Zone 20 equipment (506.9(C)(2)) is permitted in Class III, Division 1; Zone 20, 21, or 22 equipment only in Division 2 — 503.6. - Type MC, MI, TC, or TC-ER in ladder/ventilated trough/ventilated channel tray: single layer, space not less than the larger cable diameter between adjacent cables — 503.10(A)(1)(4) (exception: MC listed for Class II, Div 1). - Division 2 uses the Division 1 methods; open wiring on insulators is allowed only in sections/compartments/areas used solely for storage containing no machinery, per Article 398 with 398.15(C) protection — 503.10(B), Exception. - No uninsulated exposed parts over **30 volts (15 volts in wet…