Idaho Limited Electrical Well Driller

Key Concepts

Purpose (90.1(A)). The purpose of the Code is "the practical safeguarding of persons and property from hazards arising from the use of electricity." The Code "is not intended as a design specification or an instruction manual for untrained persons."

Adequacy (90.1(B)). Compliance plus proper maintenance results in an installation "essentially free from hazard but not necessarily efficient, convenient, or adequate for good service or future expansion of electrical use."

Relation to other standards (90.1(C)). The Code addresses the fundamental principles of protection for safety in Section 131 of IEC 60364-1.

Scope — Covered (90.2(A)). The Code covers the installation and removal of electrical conductors, equipment, and raceways; signaling and communications conductors, equipment, and raceways; and optical fiber cables and raceways for: 1. Public and private premises, including buildings, structures, mobile homes, recreational vehicles, and floating buildings 2. Yards, lots, parking lots, carnivals, and industrial substations 3. Installations of conductors and equipment that connect to the supply of electricity 4. Installations used by the electric utility — office buildings, warehouses, garages, machine shops, recreational buildings — that are not an integral part of a generating plant, substation, or control center

Covers Article 100 (Definitions) and Article 110 (Requirements for Electrical Installations).

Key Concepts

Article 100 definitions (Part I applies wherever the terms are used throughout the Code; Part II applies to installations over 1000 volts, nominal).

• Ampacity — the maximum current, in amperes, that a conductor can carry continuously under the conditions of use without exceeding its temperature rating. (NEC 2017, Page 9, Article 100)
• Continuous Load — a load where the maximum current is expected to continue for 3 hours or more. (NEC 2017, Page 8, Article 100)
• Approved — acceptable to the authority having jurisdiction. (Article 100)
• Authority Having Jurisdiction (AHJ) — an organization, office, or individual responsible for enforcing the requirements of a code or standard, or for approving equipment, materials, an installation, or a procedure. (Article 100)
• In Sight From (Within Sight) — visible and not more than 15 m (50 ft) distant from the other equipment. Both conditions must be met. (Article 100)
• Copper-Clad Aluminum Conductors — copper metallurgically bonded to an aluminum core, the copper forming a minimum of 10 percent of the cross-sectional area of a solid conductor or each strand. (Article 100)
• GFCI — the informational note states a Class A GFCI trips when current to ground is 6 mA or higher and does not trip when it is less than 4 mA. (Article 100)
• **Overcurrent…

2017 NEC Chapter 2 (Articles 210, 220, 225, 240, 250)

Key Concepts

Grounding and bonding fundamentals (Article 250) - Bonding of equipment on a grounded system connects non–current-carrying conductive materials together and to the electrical supply source to establish an effective ground-fault current path [250.4(A)(3)]. The earth shall not be considered an effective ground-fault current path [250.4(A)(5)]. - Currents that introduce noise or data errors in electronic equipment shall not be considered the objectionable currents addressed in 250.6 [250.6(D)]. - Main bonding jumpers and system bonding jumpers shall not be smaller than the sizes in Table 250.102(C)(1) [250.28(D)].

Grounding electrodes (250.52–250.53) - Metal underground water pipe: in direct contact with earth for 3.0 m (10 ft) or more [250.52(A)(1)]. - Concrete-encased electrode: at least 20 ft of bare copper conductor not smaller than 4 AWG [250.52(A)(3)(2)]. - Ground ring: at least 20 ft of bare copper not smaller than 2 AWG [250.52(A)(4)]; installed not less than 30 in. below the surface of the earth [250.53(F)]. - Pipe/conduit electrodes: not smaller than trade size 3/4, steel galvanized or metal-coated [250.52(A)(5)(a)]. - Plate electrodes: expose not less than 2 ft² of surface to exterior soil; iron or steel plates at least 1/4 in. thick [250.52(A)(7)]. - Underground metal well casings not bonded to a metal water pipe are permitted electrodes [250.52(A)(8)]. Not permitted: metal underground gas piping, aluminum, and the structures in 680.26(B)(1)/(B)(2)…

Key Concepts

Conduit bends and size limits - RMC, IMC, PVC, FMC, LFMC, and EMT all limit bends to "not more than the equivalent of four quarter bends (360 degrees total) between pull points, for example, conduit bodies and boxes." [344.26, 342.26, 352.26, 348.26, 350.26, 358.26] - RMC larger than metric designator 155 (trade size 6) shall not be used [344.20(B)]; PVC maximum is also trade size 6 [352.20(B)]. IMC maximum is trade size 4 [342.20(B)]; EMT maximum is trade size 4 [358.20(B)]; FMC maximum is trade size 4 [348.20(B)]; LFMC maximum is trade size 4 [350.20(B)]. Minimum for RMC, IMC, PVC, EMT is trade size ½.

Securing and supporting - EMT: securely fastened at intervals not to exceed 3 m (10 ft), and each run securely fastened within 900 mm (3 ft) of each outlet box, junction box, device box, cabinet, conduit body, or other tubing termination [358.30(A)]. - RMC/IMC: securely fastened within 900 mm (3 ft) of each termination; supported at intervals not exceeding 3 m (10 ft), or per Table 344.30(B)(2) for straight runs made up with threaded couplings [344.30, 342.30]. - FMC and LFMC: securely fastened within 300 mm (12 in.) of each box, cabinet, conduit body, or other conduit termination, and supported/secured at intervals not to exceed 1.4 m (4½ ft) [348.30(A), 350.30(A)]. - PVC: securely fastened within 900 mm (3 ft) of each termination [352.30(A)]; supported…

Key Concepts

• Which current to use. For general motor applications, the values in Tables 430.247 through 430.250 determine conductor ampacity, switch ratings, and branch-circuit short-circuit and ground-fault (SC/GF) protection — instead of the nameplate current [430.6(A)(1)]. Separate motor overload protection is based on the motor nameplate current rating [430.6(A)(2)]. Table 430.247 = DC, 430.248 = single-phase, 430.249 = two-phase, 430.250 = three-phase.
• Single-motor conductors. Conductors supplying a single continuous-duty motor: ampacity not less than 125 percent of motor FLC [430.22]. Rectifier-supplied dc: input side 125% of rated input current; output to motor 190% (single-phase half-wave) or 150% (single-phase full-wave) [430.22(A)(1), (A)(2)].
• Special connections. Line side of controller is 125% in both cases; between controller and motor: not less than 72 percent for wye-start, delta-run [430.22(C) — 58% × 1.25] and not less than 62.5 percent for part-winding [430.22(D) — 50% × 1.25]. Multispeed: line-side conductors sized on the highest nameplate FLC; controller-to-motor conductors not less than 125% of the winding(s) energized [430.22(B)].
• Feeders. 125% of the highest rated motor's FLC plus the sum of the FLCs of all other motors (plus non-motor loads) [430.24]. Feeder SC/GF device: largest branch-circuit SC/GF device rating plus the sum of the FLCs of the other motors [430.62(A)].
• Overload protection [430.32(A)(1)], continuous duty over 1 hp, separate overload device selected to trip at no more than: 125% of nameplate FLC for motors…

Key Concepts

• Motor full-load current comes from the NEC tables, not the nameplate. For general motor applications, the values in Tables 430.247 through 430.250 are used to determine conductor ampacity and ratings of switches and branch-circuit short-circuit and ground-fault (SCGF) protection "instead of the actual current rating marked on the motor nameplate" (430.6(A)(1)). Motors built for low speeds (less than 1200 RPM), high torques, and multispeed motors use nameplate current.
• Motor outlet loads are not 180 VA. Loads for motor outlets are calculated per 430.22, 430.24 and 440.6 (220.14(C)); for a single continuous-duty motor, 430.22 requires conductor ampacity not less than 125 percent of the motor full-load current as determined by 430.6(A)(1). The 180 VA figure belongs to general-use receptacle outlets (220.14(I)) and "other outlets" (220.14(L)).
• Overload protection — two separate maximums (430.32(A)(1)). A separate overload device responsive to motor current for a continuous-duty motor rated more than 1 hp shall be selected to trip or be rated at no more than: 125% for motors with a marked service factor 1.15 or greater; 125% for motors with a marked temperature rise 40°C or less; 115% for all other motors.
• Modified overload selection (430.32(C)). Only where the device selected under (A)(1) or (B)(1) will not start the motor or carry the load may higher settings be used, with trip current not exceeding 140% (SF 1.15 or greater), 140% (temperature…