Exam Cheat Sheet · Quick Reference
North Carolina Limited Electrical Contractor (L)
North Carolina · PSI Services Contractor
North Carolina State Portion 100 questions
Key Distinctions
EMT must be secured within 900 mm (3 ft) of each box, cabinet, conduit body, or other termination (and at intervals not over 10 ft), whereas FMC and AC cable must be secured within 12 in. of a termination.
NEC 2020 Section 358.30(A)Grounding is prohibited for electric crane circuits operating over combustible fibers in Class III locations, while the systems listed in 250.21(A) are merely permitted — not required — to be grounded; by contrast a 3-phase, 4-wire wye system whose neutral is used as a circuit conductor must be grounded per 250.20(B)(2).
NEC 2020 Sections 250.22 and 250.21(A)In supervised industrial installations with a device rated over 800 A, conductors may have an ampacity of not less than 95 percent of the device rating when the listed conditions are met, while outside Part VIII the conductor ampacity must be at least 100 percent of the device rating.
NEC 2020 Section 240.91(B)Luminaires in a fountain shall not operate on supply circuits over 150 volts between conductors, while submersible pumps and other submersible equipment are permitted at 300 volts or less between conductors.
NEC 2020 Section 680.51(B)Where service and maintenance are furnished by building management under continuous supervision, branch-circuit overcurrent devices for guest rooms without permanent cooking provisions may be accessible only to authorized management personnel, but units with permanent cooking provisions are not included in that allowance and the occupant must have ready access.
NEC 2020 Section 240.24(B)(2)Edison-base fuses are permitted only as replacements in existing installations with no evidence of overfusing or tampering, whereas Edison-base fuseholders showing overfusing must be fitted with non-removable Type S adapters so only the correct Type S ampere classification (0–15 A, 16–20 A, 21–30 A) can be installed.
NEC 2020 Sections 240.51(B), 240.52, 240.53, and 240.54A branch-circuit inverse time circuit breaker rated in amperes is permitted as the controller for all motors (as is a molded case switch rated in amperes), while an instantaneous-trip breaker may be used only if adjustable and part of a listed combination motor controller.
NEC 2020 Section 430.83(A)(2)A master alarm box is publicly accessible AND can also be operated by remote initiating devices or an auxiliary alarm system, while an auxiliary alarm box can only be operated from remote devices or an auxiliary system and a publicly accessible alarm box houses only a manually operated transmitter.
NFPA 72 National Fire Alarm and Signaling Code, Chapter 3 — 3.3.12 Alarm Box (3.3.12.1, 3.3.12.4, 3.3.12.5)If the top of the girder is within 4 in. (100 mm) of the ceiling it is treated as a beam and is a factor in the number and location of detectors; if more than 4 in. from the ceiling it is not a factor.
NFPA 72 National Fire Alarm and Signaling Code, Chapter 3 — 3.3.37.2 GirderIn mediation an independent third-party mediator facilitates dialogue while the parties themselves set the terms of any agreement; in collaborative law the parties negotiate through their own advocates (usually lawyers) with no neutral mediator or arbitrator involved.
NASCLA Contractors Guide, Contract Management chapter — Alternative Dispute Resolution sectionFor voltage ratings up to and including 2000 volts the minimum conductor size is 14 AWG copper or 12 AWG aluminum/copper-clad aluminum, but conductors may be connected in parallel only in sizes 1/0 AWG and larger.
NEC 2020 Section 310.3(A)16 AWG copper is limited to a 10-ampere device with continuous load not over 8 amperes (with listed/marked branch-circuit-rated protection or Class CC, J, or T fuses), while 5.6 amperes is the continuous-load limit that applies to 18 AWG copper.
NEC 2020 Section 240.4(D)(2)Key Terms
Formulas to Know
Ampacity ≥ noncontinuous load + (125% × continuous load); e.g., (100 A × 1.25) + 30 A = 155 A125% × FLC of largest motor + sum of FLCs of remaining motors; e.g., (1.25 × 15.2) + 15.2 + 15.2 = 49.4 ASeparate overload device ≤ 125% × nameplate FLC for motors with a marked service factor ≥ 1.15 or marked temperature rise ≤ 40°C; ≤ 115% × nameplate FLC for all other motors. These are maximums, not a range: 30 A → 37.5 A max (service factor 1.15) or 34.5 A max (other motors)Table 430.52: 250% × FLC (single-phase); if the motor will not start, next higher standard size, but never over 400% of FLC for FLC ≤100 A (50 A × 2.5 = 125 A → 150 A; 60 A × 4.0 = 240 A max)Conductors ≥ 125% × RLA (28 A → 35 A; 30 A → 37.5 A; 20 A → 25 A); branch-circuit OCPD ≤ 175% × RLA (30 A → 52.5 A → 50 A standard size, no rounding up in the 2020 NEC; 20 A → 35 A), increased only if needed to start, to a maximum 225% of RLAAmpacity ≥ 115% × generator nameplate current; 80 A × 1.15 = 92 A; 200 A × 1.15 = 230 A(Area in sq ft × 3 VA/sq ft) + (1,500 VA × number of small-appliance circuits) + (1,500 VA × number of laundry circuits); e.g., 2,000 sq ft → 6,000 + 3,000 + 1,500 = 10,500 VA; per-unit totals × number of units for multifamily before demand factors; dwelling units only: a retail store uses the Table 220.12 unit load, 1.9 VA/sq ft, plus 180 VA per receptacle outletOne dwelling unit (220.82(B)): general calculated load = 100% of first 10 kVA + 40% of the remainder; multifamily (Table 220.84): apply demand factor by number of units, e.g., 41% for 12–13 units meeting 220.84(A)For rated primary current of 9 A or more: device ≤ 125% × rated primary current (12 A × 1.25 = 15 A); next higher standard size allowed only when 125% does not land on a standard ratingTotal ampacity = ampacity per set × number of sets (350 kcmil Cu at 90°C = 350 A; 2 sets = 700 A); for grounded conductor sizing add parallel areas (2 × 350 = 700 kcmil → Table 250.102(C)(1) over 600 through 1,100 kcmil = 2/0 AWG Cu), and each parallel grounded conductor shall not be smaller than 1/0 AWG per 250.24(C)(2)