Exam Cheat Sheet · Quick Reference
ICC F18 Residential Electrician Exam (2014 NEC)
National · Pearson Vue
National State Portion 60 questions
Key Distinctions
A service drop is the overhead conductors between the utility electric supply system and the service point, overhead service conductors run between the service point and the first point of connection to the service-entrance conductors, and a service lateral is the underground equivalent of a service drop.
NEC 2014 Article 100 (Definition: Service Drop)Exposed means on or attached to the surface or behind panels designed to allow access, while concealed means rendered inaccessible by the structure or finish of the building.
NEC 2014 Article 100 (Definition: Exposed — as applied to wiring methods)Wet locations include installations underground, in concrete slabs or masonry in direct contact with the earth, locations subject to saturation and unprotected locations exposed to weather; roofed open porches and basements with moderate moisture are damp, and a building under construction is a dry location temporarily subject to dampness.
NEC 2014 Article 100 (Definitions: Location, Wet; Location, Damp; Location, Dry)A single receptacle is a single contact device with no other contact device on the same yoke; a multiple receptacle has two or more contact devices on the same yoke (box count, ampere rating and supply circuit are irrelevant to the definition).
NEC 2014 Article 100 (Definition: Receptacle)A multifamily dwelling is a building containing three or more dwelling units; a building with exactly two units is a two-family dwelling.
NEC 2014 Article 100 (Definition: Dwelling, Multifamily)Ampacity is the maximum current a conductor can carry continuously without exceeding its temperature rating, interrupting rating is the highest current at rated voltage a device is identified to interrupt, short-circuit current rating is the prospective symmetrical fault current an apparatus can be connected to without damage, and demand factor is the ratio of maximum demand to total connected load.
NEC 2014 Article 100 (Definition: Ampacity)Type 2 SPDs are permanently connected on the load side of the service disconnect overcurrent device (including at a branch panel), Type 1 is on the line side of the service disconnect, Type 3 is at the point of utilization, and Type 4 are component SPDs.
NEC 2014 Article 100 (Definition: Surge-Protective Device)A multiwire branch circuit has two or more ungrounded conductors with voltage between them plus a grounded conductor with equal voltage to each and connected to the system neutral, while an individual branch circuit supplies only one utilization equipment, a general-purpose branch circuit supplies two or more receptacles or outlets for lighting and appliances, and an appliance branch circuit supplies appliance outlets with no permanently connected luminaires.
NEC 2014 Article 100 (Definition: Branch Circuit, Multiwire)Terminations for equipment on circuits rated 100 amperes or less (or marked for 14 AWG through 1 AWG) use conductors rated 60°C or higher-rated conductors whose ampacity is taken at the 60°C value unless listed/identified otherwise, but for motors marked design letter B, C, or D conductors insulated 75°C (167°F) or higher are permitted provided ampacity does not exceed the 75°C value.
NEC 2014 Section 110.14(C)(1)(a)Elevation alone requires a minimum of 2.5 m (8 ft) above the floor or working surface for 50 to 300 volts, but 2.6 m (8-1/2 ft) for 301 to 600 volts.
NEC 2014 Section 110.27(A)(4)For nominal voltage to ground of 0–150 volts the minimum clear working depth is 914 mm (3 ft) for Condition 1, 2, or 3, while the 3 ft 6 in. and 4 ft values belong to the 151–600 volt row.
NEC 2014 Table 110.26(A)(1)Service equipment in other than dwelling units must be legibly field marked with the maximum available fault current and the date of the calculation; dwelling-unit service equipment is not required to carry this marking.
NEC 2014 Section 110.24(A)Aluminum has roughly 1.6 times the resistance of copper, so its voltage-drop K value is 21.2 versus 12.9 for copper.
Key Terms
Formulas to Know
VD = (2 × K × I × L) / CM, where K = 12.9 for copper and 21.2 for aluminum, L = one-way length in ft, CM = circular mils; the factor 2 accounts for the out-and-back length of both conductors. Example: (2 × 12.9 × 16 A × 60 ft) / 6,530 cmil = 3.79 V.Allowable VD = source voltage × percent limit; L = (VD × CM) / (2 × K × I). Example: 240 V × 0.03 = 7.2 V; (7.2 × 16,510) / (2 × 12.9 × 40) = 115 ft one-way.CM = (2 × K × I × L) / VD, then select the smallest standard size with at least that many circular mils. Example: 120 V × 0.03 = 3.6 V; (2 × 12.9 × 20 × 80) / 3.6 = 11,466 cmil → 8 AWG (16,510 cmil).% VD = voltage drop / source voltage. Example: 8.4 V / 240 V = 3.5 percent (exceeds the 3 percent recommended for a branch circuit alone).Noncontinuous load + 125% of continuous load. Example: 50 A + (30 A × 1.25) = 87.5 A.General lighting = area (sq ft) × 3 VA/sq ft; each small-appliance circuit = 1,500 VA; each laundry circuit = 1,500 VA; sum for total. Example: 2,000 sq ft × 3 = 6,000 VA + (2 × 1,500) + 1,500 = 10,500 VA; per-unit totals are multiplied by the number of units before demand factors (4 × 8,100 VA = 32,400 VA).Per-conductor table ampacity × number of parallel sets. Example: 350 kcmil copper at 90°C = 350 A; two sets = 700 A.Distance between the two bend marks = multiplier × offset depth (multiplier 1.4 for 45°, e.g., 1.4 × 4 in. = 5-5/8 in.); shrink = shrink-per-inch × offset depth (1/4 in. per in. for the 4-in. offset = 1 in.; 1/2 in. per in. for the 9-in. offset = 4-1/2 in.), and marks move toward the far end by the shrink amount (30 in. + 1 in. = 31 in.).Mark = stub height − take-up (take-up 5 in. for 1/2" EMT, 6 in. for 3/4" EMT). Examples: 18 − 5 = 13 in.; 12 − 6 = 6 in.Side marks = 2.5 × obstruction height on each side of the center mark (2.5 × 6 in. = 15 in.); center bent 45°, sides bent 22-1/2°; shrink = 3/16 × obstruction height (3/16 × 6 = 1-1/8 in.).