ICC F16 Master Electrician Exam (2014 NEC)

Key Concepts

Article 100 definitions (Part I applies throughout the Code; Part II applies only to installations over 600 volts, nominal):

• Ampacity — the maximum current, in amperes, a conductor can carry continuously under the conditions of use without exceeding its temperature rating.
• Continuous Load — maximum current expected to continue for 3 hours or more.
• In Sight From — visible and not more than 15 m (50 ft) distant; both conditions must be met.
• Demand Factor — ratio of maximum demand to total connected load.
• Overload — operation in excess of normal full-load rating or of rated ampacity; a fault such as a short circuit or ground fault is not an overload.
• Overcurrent Protective Device, Branch-Circuit — interrupting ratings no less than 5000 amperes.
• Volatile Flammable Liquid — flash point below 38°C (100°F), or above its flash point.
• Copper-Clad Aluminum — copper forms a **minimum…

Key Concepts

Number of services and conductors considered outside (Art. 230) - One service per building unless permitted otherwise; additional services are permitted where capacity requirements are in excess of 2000 amperes at a supply voltage of 1000 volts or less — 230.2(C)(1). - Conductors are considered outside a building where installed in conduit under not less than 450 mm (18 in.) of earth beneath a building; 50 mm (2 in.) of concrete applies to 230.6(1) and (2) — 230.6.

Clearances and installation - Overhead service conductors over residential property and driveways, and commercial areas not subject to truck traffic where the voltage does not exceed 300 volts to ground: minimum 3.7 m (12 ft) from final grade. Where the voltage exceeds 300 volts to ground, 4.5 m (15 ft) — 230.24(B)(2), (B)(3). - Roof overhang reduction to not less than 450 mm (18 in.) where voltage between conductors does not exceed 300, not…

Key Concepts

Feeder conductor sizing (215.2). Feeder conductors must have ampacity not less than the load calculated per Parts III, IV, and V of Article 220, and shall be sized to the larger of: (a) noncontinuous load plus 125 percent of the continuous load, or (b) the maximum load after adjustment/correction factors [215.2(A)(1)]. Exception No. 1: where the assembly, including the overcurrent devices protecting the feeder, is listed for operation at 100 percent of its rating, ampacity may be not less than continuous plus noncontinuous load. Exception No. 2: grounded conductors not connected to an overcurrent device may be sized at 100 percent of continuous plus noncontinuous load. Feeder ampacity shall not be less than that of the service conductors where the feeder carries the total load supplied by service conductors with an ampacity of 55 amperes or less [215.2(A)(3)]. The feeder grounded conductor shall not be smaller than required by 250.122 [215.2(A)(2)].

Key Concepts

Branch-circuit ratings and voltage limits - Ratings for other than individual branch circuits are 15, 20, 30, 40, and 50 amperes (210.3). 25 A is a standard device rating but not a recognized multioutlet branch-circuit rating. - Circuits exceeding 277 V to ground, not exceeding 600 V between conductors, may supply electric-discharge luminaires mounted not less than 6.7 m (22 ft) on poles for outdoor areas such as parking lots (210.6(D)(1)(a)); 5.5 m (18 ft) applies to other structures such as tunnels (210.6(D)(1)(b)). - AFCI combination of a supplemental arc protection breaker plus an outlet branch-circuit AFCI at the first outlet: wiring to the first outlet may not exceed 15.2 m (50 ft) for 14 AWG or 21.3 m (70 ft) for 12 AWG (210.12(A)(3)(b)).

2014 NEC

Key Concepts

Rigid PVC Conduit (Article 352) - PVC is permitted exposed; PVC used exposed in areas of physical damage must be identified for the use. The Informational Note states Schedule 80 is identified for areas of physical damage — 352.10(F). - Prohibited where subject to ambient temperatures in excess of 50°C (122°F) unless listed otherwise — 352.12(D). - Size: not smaller than trade size 1/2, not larger than trade size 6 — 352.20(A) and (B). - Conductors or cables rated higher than the conduit's listed temperature rating may be installed, provided they are not operated above the conduit's listed rating — 352.10(I). - PVC may support nonmetallic conduit bodies not larger than the largest trade size of an entering raceway; those bodies shall not support luminaires or other equipment and shall contain no devices other than splicing devices per 110.14(B) and 314.16(C)(2) — 352.10(H). - Secure within 900 mm (3 ft)…

Key Concepts

Article 410 — Luminaires, Lampholders, and Lamps - Bathtub/shower zone (410.10(D)): No parts of cord-connected luminaires, chain-, cable-, or cord-suspended luminaires, lighting track, pendants, or ceiling-suspended (paddle) fans within a zone 900 mm (3 ft) horizontally and 2.5 m (8 ft) vertically from the top of the bathtub rim or shower stall threshold. The zone is all encompassing. - Roof decking (410.10(F)): Not less than 38 mm (1-1/2 in.) from the lowest surface of metal-corrugated sheet roof decking to the top of the luminaire. - Over combustible material (410.12): Lampholders shall be unswitched type; unless an individual switch is provided for each luminaire, located at least 2.5 m (8 ft) above the floor or located/guarded so lamps cannot be readily removed or damaged. - Clothes closets (410.16(C)): 300 mm (12 in.) for surface-mounted incandescent or LED with completely enclosed light source on wall above door or ceiling; 150 mm (6 in.) for…

Key Concepts

Snap switches and controllers. An ac-only general-use snap switch may serve as the controller for a stationary motor rated 2 hp or less and 300 volts or less, provided the motor full-load current is not more than 80 percent of the switch rating (430.83(C)(2)). A general-use switch under 430.83(C)(1) must instead be rated at twice the motor FLC. Article 404 parallels this: an ac general-use snap switch controls motor loads not exceeding 80 percent of its ampere rating at rated voltage (404.14(A)(3)); an ac/dc general-use snap switch controls inductive loads not exceeding 50 percent of its ampere rating, and switches rated in horsepower are suitable for motor loads within their rating (404.14(B)). Snap switches rated 347 volts ac must be listed, and the ampere rating shall not be less than 15 amperes at 347 volts ac (404.14(D)). General-use dimmer switches may be used only to control permanently installed incandescent luminaires unless listed…

Key Concepts

Use table values, not nameplate. For general motor applications, current ratings for conductors, switches, and branch-circuit short-circuit/ground-fault (SCGF) protection come from Table 430.247–430.250, not the nameplate [430.6(A)(1)]. Separate overload protection is based on the motor nameplate current rating [430.6(A)(2)].

Single motor conductors. Conductors supplying a single continuous-duty motor shall have an ampacity of not less than 125 percent of the motor full-load current [430.22]. Special cases: wye-start/delta-run — not less than 72 percent between controller and motor [430.22(C)]; part-winding — not less than 62.5 percent between controller and motor [430.22(D)]; dc motor from a single-phase rectifier — not less than 150 percent (full-wave) or 190 percent (half-wave) between the rectifier field wiring output terminals and the motor [430.22(A)].

Feeder conductors. 125 percent of the highest rated motor's full-load current plus the sum of the full-load currents of all other motors [430.24].

Key Concepts

Class III Locations (Article 503) - Maximum surface temperatures: 165°C (329°F) for equipment not subject to overloading; 120°C (248°F) for equipment (such as motors or power transformers) that may be overloaded — 503.5. - Zone equipment: equipment listed/marked per 506.9(C)(2) for Zone 20 is permitted in Class III, Division 1; Zone 20, 21, or 22 marked equipment is permitted in Class III, Division 2 — 503.6. - Division 1 tray wiring: Types MC, MI, TC, or TC-ER in ladder, ventilated trough, or ventilated channel trays must be a single layer with spacing not less than the larger cable diameter. Exception: Type MC cable listed for Class II, Division 1 may be installed without that spacing — 503.10(A)(1)(4) Exception. - Division 2 follows Division 1 methods; open wiring on insulators is permitted only in sections, compartments, or areas used solely for storage and containing no machinery, per Article 398 with 398.15(C) protection —…