North Carolina Electrical Contractor - Plumbing and Heating (SP-PH)

North Carolina Electrical Contractor – Plumbing and Heating (SP-PH)

Key Concepts

Fundamental principle — the earth is not a fault path - "The earth shall not be considered as an effective ground-fault current path" (NEC 2020, 250.4(A)(5)). The effective path must be a low-impedance circuit capable of safely carrying the maximum ground-fault current likely to be imposed on it from any point on the wiring system to the electrical supply source. - Under ungrounded systems, 250.4(B)(4) likewise states "The earth shall not be considered as an effective fault-current path."

Objectionable current (250.6(B)) If multiple grounding connections result in objectionable current and the requirements of 250.4(A)(5) or (B)(4) are met, permitted alterations are: (1) discontinue one or more but not all of such grounding connections; (2) change the locations of the grounding connections; (3) interrupt the continuity of the conductor or conductive path causing the objectionable current; (4) take other suitable remedial and approved…

Topic: Overcurrent Protection — NEC 2020, Article 240 All citations: NEC 2020, Article 240

Key Concepts

Scope of the article (240.1): Parts I through VII cover overcurrent protection and devices not more than 1000 volts, nominal. Part VIII covers supervised industrial installations at not more than 1000 volts, nominal. Part IX covers overcurrent protection over 1000 volts, nominal.

Circuit breakers - 240.80 Method of Operation: Circuit breakers shall be trip free and capable of being closed and opened by manual operation. Normal operation by other than manual means (electrical, pneumatic) is permitted if means for manual operation are also provided. - 240.81 Indicating: Breakers shall clearly indicate whether open "off" or closed "on." Where handles operate vertically, the "up" position is "on." - 240.83(A)/(B) Marking: Ampere rating marked durably and visibly; breakers rated 100 amperes or less and 1000 volts or less shall have the ampere rating molded, stamped, etched or similarly marked into…

North Carolina Electrical Contractor – Plumbing and Heating (SP-PH) · 8 questions (20%) · NEC 2020

Key Concepts

Conductor construction and minimum size - Minimum conductor size for voltage ratings up to and including 2000 volts: 14 AWG copper or 12 AWG aluminum or copper-clad aluminum, except as permitted elsewhere in the Code — 310.3(A). - Where installed in raceways, conductors 8 AWG and larger shall be stranded, unless specifically permitted or required elsewhere to be solid — 310.3(C). - Conductors may be connected in parallel (joined at both ends) only in sizes 1/0 AWG and larger — 310.10(G)(1). Paralleled conductors in each phase/neutral must be the same length, same material, same circular mil size, same insulation type, and terminated in the same manner — 310.10(G)(2).

North Carolina Electrical Contractor – Plumbing and Heating (SP-PH) · NEC 2020, Article 314

Key Concepts

Scope (314.1). Article 314 covers installation and use of all boxes and conduit bodies used as outlet, device, junction, or pull boxes, and handhole enclosures. Cast metal, sheet metal, nonmetallic, and other boxes such as FS, FD, and larger boxes are not classified as conduit bodies.

Round boxes (314.2). Round boxes shall not be used where conduits or connectors requiring the use of locknuts or bushings are to be connected to the side of the box.

Nonmetallic boxes (314.3). Permitted only with open wiring on insulators, concealed knob-and-tube wiring, cabled wiring methods with entirely nonmetallic sheaths, flexible cords, and nonmetallic raceways. Exception No. 1: where internal bonding means are provided between all entries, nonmetallic boxes are permitted with metal raceways or metal-armored cables. Exception No. 2: nonmetallic boxes listed for the purpose with integral bonding means and a…

NC Electrical Contractor (SP-PH) · 5 questions · 12% of exam

Key Concepts

Determining the current to use (430.6) - Conductor ampacity, switch ratings, and branch-circuit short-circuit/ground-fault protection are based on the values in Table 430.247 through Table 430.250 — not the nameplate current — except for motors built for low speeds (less than 1200 RPM), high torques, and multispeed motors, where nameplate ratings are used [430.6(A)(1)]. - Separate motor overload protection is based on the motor nameplate current rating [430.6(A)(2)]. - Highest or smallest rated motor for 430.24 is determined from the table full-load currents [430.17].

Branch-circuit and feeder ampacity (Part II) - Conductors supplying a single motor in continuous duty: not less than 125 percent of the motor full-load current rating as determined by 430.6(A)(1) [430.22]. - Wye-start, delta-run: conductors between controller and motor not less than 72 percent of motor FLC (Informational Note: 58% × 1.25) [430.22(C)]. - **DC motor from…

Based on NEC 2020 — Article 210 (Branch Circuits) and Article 220 (Branch-Circuit, Feeder, and Service Load Calculations)

Key Concepts

Required dwelling branch circuits (NEC 2020, 210.11(C)) - 210.11(C)(1): In addition to the branch circuits required by other parts of the section, two or more 20-ampere small-appliance branch circuits shall be provided for all receptacle outlets specified by 210.52(B). - 210.52(B)(1): Those circuits serve all wall and floor receptacle outlets covered by 210.52(A), all countertop outlets covered by 210.52(C), and receptacle outlets for refrigeration equipment. 210.52(B)(3): receptacles serving kitchen countertop surfaces shall be supplied by not fewer than two small-appliance branch circuits; no small-appliance branch circuit shall serve more than one kitchen. - 210.11(C)(2): at least one additional 20-ampere laundry branch circuit (210.52(F)); no other outlets. - 210.11(C)(3): one or more 120-volt, 20-ampere bathroom branch circuit(s) (210.52(D)); such circuits shall have no other outlets. - 210.11(C)(4): at least one 120-volt, 20-ampere branch circuit for…

North Carolina Electrical Contractor — Plumbing and Heating (SP-PH)

Subtopics: Air conditioners; Residential, commercial, and industrial equipment; Space heating equipment and boilers

Key Concepts

Appliances (Article 422)

• All appliances supplied by 50 volts or higher shall be listed — NEC 422.6.
• Storage-type water heaters: the branch-circuit overcurrent device and conductors for fixed storage-type water heaters having a capacity of 450 L (120 gal) or less shall be sized not smaller than 125 percent of the rating of the water heater — NEC 422.13.
• Water heater controls: all storage or instantaneous-type water heaters shall be equipped with a temperature-limiting means in addition to the control thermostat, to disconnect all ungrounded conductors. It must be installed to sense maximum water temperature and be either a trip-free, manually reset type or a type having a replacement element — NEC 422.47.
• Flexible cord lengths (422.16(B)):
• In-sink waste disposer: not less than 450 mm…

North Carolina Electrical Contractor – Plumbing and Heating (SP-PH) | 3 questions, 8% of exam

Key Concepts

Code structure and enforceability (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 and may supplement or modify the requirements in Chapters 1 through 7. Chapter 8 (Communications Systems) is NOT subject to the requirements of Chapters 1 through 7 except where the requirements are specifically referenced in Chapter 8. Chapter 9 consists of tables applicable as referenced. (NEC 2020/2017, 90.3) - Mandatory rules identify actions specifically required or prohibited and are characterized by the terms "shall" or "shall not." Permissive rules are characterized by "shall be permitted" or "shall not be required." (90.5(A), 90.5(B)) - Explanatory material, such as informational notes, is informational only and not enforceable as requirements of the Code. Informative annexes are likewise not part of…

Key Concepts

Board structure and authority - The Board consists of one member from the N.C. Department of Insurance designated by the Commissioner of Insurance; one member who has satisfied the requirements for an unlimited license representing the N.C. Association of Electrical Contractors; and five members appointed by the Governor (electrical engineering faculty member, a chief electrical inspector, an unlimited-license contractor representing the Carolinas Electrical Contractors Association, and two public members) — G.S. 87-39(a). - "Members of the Board shall serve staggered seven-year terms." Members shall not serve consecutive, complete terms; all members must be N.C. residents during their tenure — G.S. 87-39(b), (c), (d). - Electrical contracting is "engaging or offering to engage in the business of installing, maintaining, altering or repairing any electric work, wiring, devices, appliances or equipment" (G.S. 87-43). In each separate place of business, at least one listed qualified individual must be regularly on active duty (G.S. 87-43; Chapter…