ICC F19 Maintenance Electrician Exam (2014 NEC)

2014 NEC

Key Concepts

Code arrangement (Article 90). Chapters 1, 2, 3, and 4 apply generally; Chapters 5, 6, and 7 apply to special occupancies, special equipment, or other special conditions. Chapter 8 covers communications systems and is not subject to Chapters 1 through 7 except where specifically referenced. Chapter 9 consists of tables that are applicable as referenced — i.e., only as referenced elsewhere in the Code (90.3). Informational notes are explanatory only and are not enforceable (90.5(C)).

Working space, 600 volts nominal or less (110.26). - Depth: not less than Table 110.26(A)(1), measured from exposed live parts or from the enclosure/opening if enclosed. - Width (110.26(A)(2)): the width of the equipment or 762 mm (30 in.), whichever is greater; the space must permit at least a 90-degree opening of equipment doors or hinged panels. - Height (110.26(A)(3)): clear from grade, floor, or platform to 2.0 m (6-1/2 ft) or the height of the equipment, whichever is greater. Associated equipment above or below may extend not more than 150 mm (6 in.) beyond the front. - Clear spaces (110.26(B)): working space shall not be used for storage. - Entrance/egress, large equipment (110.26(C)(2)): equipment rated 1200 amperes or more and over 1.8 m (6 ft) wide containing overcurrent, switching, or control devices requires an entrance not less than 610 mm (24 in.) wide and 2.0 m (6-1/2 ft) high at each end,…

Key Concepts

Switches (Article 404) - Article 404 applies to switches, switching devices, and circuit breakers used as switches operating at 1000 volts and below, unless specifically referenced elsewhere for higher voltages — 404.1. - Operating handle in its highest position: center of grip not more than 2.0 m (6 ft 7 in.) above the floor or working platform — 404.8(A). - Time switches/flashers: exception permits no barriers where accessible only to qualified persons and energized parts within 152 mm (6.0 in.) of the manual adjustment or switch are covered by suitable barriers — 404.5. - Snap switch ratings: ac general-use snap switch may control motor loads not exceeding 80 percent of the switch ampere rating at rated voltage — 404.14(A)(3); ac/dc general-use snap switch may control inductive loads not exceeding 50 percent of the ampere rating at the applied voltage (resistive loads up to the full ampere rating) — 404.14(B). - 347-volt ac specific-use snap switches: ampere rating not less than 15 amperes at 347 volts ac — 404.14(D)(2). - General-use dimmer switches control only permanently installed incandescent luminaires unless listed for other loads — 404.14(E). - Knife switches rated over 1200 amperes at 250 volts or less (and over 1000 amperes at 251–1000 volts) are isolating switches only, not opened under load — 404.13(A). Knife switches rated 600 to 1000 volts designed to break current over 200 amperes need renewable/quick-break…

Key Concepts

Scope and general determinations - Article 409 covers industrial control panels intended for general use operating at 1000 volts or less (409.1). - Parts II, III, and IV of Article 430 do not apply to motor circuits rated over 1000 volts, nominal (430.21, 430.31, 430.51). - For general motor applications, conductor ampacity, switch ratings, and branch-circuit short-circuit/ground-fault protection are determined from Table 430.247 through Table 430.250 — not the nameplate current (430.6(A)(1)). Separate motor overload protection is based on the motor nameplate current rating (430.6(A)(2)). - Motor time rating marking shall be 5, 15, 30, or 60 minutes, or continuous (430.7(A)(6)). - Control circuit devices with screw-type pressure terminals used with 14 AWG or smaller copper conductors: minimum torque 0.8 N·m (7 lb-in.) unless identified for a different value (430.9(C)).

Conductors (Part II) - Single continuous-duty motor: conductors not less than 125 percent of motor FLC per 430.6(A)(1) (430.22). - DC motor from rectified single-phase supply, conductors between rectifier field wiring output terminals and motor: 190 percent for a single-phase, half-wave bridge; 150 percent for a single-phase, full-wave bridge (430.22(A)(1), (2)). - Wye-start, delta-run: conductors between controller and motor not less than 72 percent of FLC (430.22(C)). - Part-winding connected motor: conductors between controller and motor not less than 62.5 percent of FLC (430.22(D)). - Feeder tap not more than 7.5 m (25 ft) long: tap conductors must have ampacity…

Key Concepts

Article 310 — Conductors - Conductors may be paralleled only in sizes 1/0 AWG and larger [310.10(H)(1)]. Exception No. 1 permits smaller than 1/0 AWG for control power to indicating instruments, contactors, relays, solenoids and similar control devices, or for frequencies of 360 Hz and higher, provided they are in the same raceway or cable, each conductor can carry the entire load current, and overcurrent protection prevents exceeding any single conductor's ampacity. - Paralleled conductors must be the same length, same conductor material, same circular mil area, same insulation type, and terminated in the same manner [310.10(H)(2)]. They are permitted to be run in separate cables or raceways [310.10(H)(3)] — a common raceway is not required. - Direct-burial cables rated above 2000 volts shall be shielded [310.10(F)]; Exception No. 1 permits nonshielded multiconductor cables rated 2001–2400 volts with an overall metallic sheath or armor. - Where more than one ampacity applies, use the lowest [310.15(A)(2)]; the Exception permits the higher ampacity beyond the point of transition for 10 ft or 10 percent of the circuit length figured at the higher ampacity, whichever is less. - Adjustment factors do not apply to underground conductors entering/leaving an outdoor trench protected by RMC, IMC, PVC, or RTRC not exceeding 10 ft, where the number of conductors does not exceed four [310.15(B)(3)(a)]. - Rooftop sunlight temperature adders apply per Table 310.15(B)(3)(c); **Type XHHW-2 is…

Key Concepts

Grounding electrodes (250.52(A)) - Metal building frame qualifies where at least one structural metal member is in direct contact with earth for 3.0 m (10 ft) or more — 250.52(A)(2)(1). - Concrete-encased electrode: at least 6.0 m (20 ft) of bare copper not smaller than 4 AWG (or 1/2 in. rebar), encased in at least 50 mm (2 in.) of concrete — 250.52(A)(3). - Ground ring: at least 20 ft of bare copper not smaller than 2 AWG, encircling the structure in direct contact with earth — 250.52(A)(4). - Rod and pipe electrodes: not less than 2.44 m (8 ft) long; pipe/conduit not smaller than trade size 3/4 and, if steel, galvanized or metal-coated — 250.52(A)(5)(a); rod-type stainless/copper or zinc coated steel at least 5/8 in. diameter unless listed — (b). - Plate electrodes: expose not less than 2 ft²; bare or conductively coated iron/steel at least 1/4 in. thick; solid uncoated nonferrous at least 0.06 in. — 250.52(A)(7). - Not permitted: metal underground gas piping and aluminum — 250.52(B).

Key Concepts

Health care facilities (Article 517) - Patient Care Vicinity is the space extending 1.8 m (6 ft) beyond the normal location of the patient bed, chair, table, treadmill, or other patient-supporting device, and extending vertically to 2.3 m (7 ft 6 in.) above the floor — 517.2. - Normal and essential branch-circuit panelboard equipment grounding terminal buses serving the same individual patient care vicinity must be connected with an insulated continuous copper conductor not smaller than 10 AWG; it may be broken to terminate on the bus in each panelboard — 517.14. - An isolated ground receptacle shall not be installed within a patient care vicinity — 517.16. - General care patient bed location: at least two branch circuits (one critical branch, one normal), not part of a multiwire branch circuit — 517.18(A); a minimum of eight receptacles, all listed and identified "hospital grade" — 517.18(B). - Critical care patient bed location: a minimum of 14 receptacles, at least one connected to the normal-system branch circuit or to a critical branch circuit on a different transfer switch — 517.19(B)(1). - Hospital essential electrical systems comprise three branches: life safety, critical, equipment — 517.30(B)(1). The life safety and critical branches must have all functions automatically restored within 10 seconds after interruption of the normal source — 517.31. - Wet procedure locations: either a system limiting first-fault ground-fault current to a low…