Exam Cheat Sheet · Quick Reference

North Carolina Electrical Contractor - Ground Water Pump (SP-WP)

North Carolina  ·  PSI Services Contractor

Verified, not estimated. Every figure below is drawn from the official exam structure we maintain — question counts, passing standard and topic weighting. Practice questions are grounded in the source law with statute citations. We omit any figure we can't verify rather than guess at it.
Total questions
40
Passing score
70%
Exam time
180 min
Administered by
PSI Services Contractor
Format
Reference materials allowed

North Carolina State Portion 40 questions

Bonding and Grounding 7 Q · 18%
Systems and equipment requiring grounding and ground-fault protectionLocation of connection and required interconnectionsGrounded, grounding, and grounding electrode conductorsConductor identification and color codingBonding jumpersEquipment grounding conductorsMethods of grounding and bonding, equipment and conductor specificationsBonding conductor connectionsTermination
Overcurrent Protection 3 Q · 8%
Location in circuitSizing requirementsCircuit breakersPlug and cartridge fuses
Wiring Methods and Terminations 9 Q · 22%
Permitted applications and usagesCharacteristicsPermitted applications and usagesCharacteristicsProtection from damagePermitted usages and ampacity ratingsCharacteristicsMiscellaneousOutdoors
Boxes and Fittings 3 Q · 8%
General informationSizing requirements
Motors and Control Wiring 5 Q · 12%
General informationBranch circuit and feeder ampacityOverload protectionShort-circuit and ground-fault protectionDisconnects/controllersTypeLocationSeparation of conductors
Load Calculations 3 Q · 8%
Branch circuitsTotal computed loadConductor ampacity requirementsOvercurrent protective device sizingLow-voltage
General 2 Q · 5%
DefinitionsInstallation requirements
Laws, Rules, Basic Business Practices, and Practical Applications 8 Q · 20%
Electrical Contractors Licensing Law (General Statutes Chapter 87, Article 4)Board’s Rules for the Implementation of the Electrical Contractors Licensing Law (Title 21, North Carolina Administrative Code, Chapter 18B)NASCLA Contractors’ Guide to Business, Law and Project Management -North Carolina Electrical Edition

Key Distinctions

NEC Chapter 8 (Communications Systems)vsNEC Chapters 1 through 7

Per 90.3, Chapter 8 is NOT subject to the requirements of Chapters 1 through 7 except where those requirements are specifically referenced in Chapter 8.

NEC 2020 Section 90.3
Informational notes / explanatory materialvsEnforceable Code requirements

Per 90.5(C), informational notes are included for informational purposes only and are not enforceable as requirements of the Code.

NEC 2020 Section 90.5(C)
Optional dwelling calculation, 220.82(B) (new dwelling unit)vsExisting dwelling calculation, 220.83(A) (no added A/C or electric space heating)

220.82(B) takes not less than 100% of the first 10 kVA plus 40% of the remainder, while 220.83(A) takes the first 8 kVA at 100% and the remainder at 40%.

NEC 2020 Section 220.82(B)
Feeder/branch-circuit disconnect for not more than two 2-wire branch circuits — 225.39(B)vsFeeder disconnect for a one-family dwelling — 225.39(C)

The two-circuit installation requires a rating of not less than 30 amperes, while the one-family dwelling feeder disconnect requires not less than 100 amperes, 3-wire.

NEC 2020 Section 225.39(B)
One-family dwelling feeder disconnect — 225.39(C)vs'All others' feeder/branch-circuit disconnect — 225.39(D)

The 100-ampere, 3-wire minimum applies specifically to the dwelling's own feeder disconnect; all other installations (such as a detached garage supplied by a feeder, not serving as the dwelling's main disconnect) require not less than 60 amperes.

NEC 2020 Section 225.39(C)
Overhead open conductor clearance over areas accessible to pedestrians only (225.18(1))vsOverhead open conductor clearance over public streets and areas subject to truck traffic (225.18(4))

Where the voltage does not exceed 150 volts to ground and the area is accessible to pedestrians only, clearance is not less than 3.0 m (10 ft); over public streets, alleys, roads, parking areas subject to truck traffic and nonresidential driveways it is not less than 5.5 m (18 ft).

NEC 2020 Section 225.18(1)
Nontime-delay fuse for AC polyphase motor (Table 430.52)vsDual element (time-delay) fuse for AC polyphase motor (Table 430.52)

Nontime-delay fuses are rated at 300% of motor full-load current, while dual element time-delay fuses have a maximum rating of 175% of full-load current (other than wound-rotor).

NEC 2020 Table 430.52, NEC 430.52(C)(1), NEC 240.6(A)
Motor branch-circuit conductors (430.22)vsMotor feeder conductors (430.24)

Branch-circuit conductors for a single continuous-duty motor must be not less than 125% of that motor's full-load current, while feeder conductors must be not less than 125% of the highest-rated motor plus the sum of the full-load currents of the other motors.

NEC 2020 Section 430.22
Conductors between controller and a part-winding motor (NEC 2020, 430.22(D))vsLine-side branch-circuit conductors / wye-start delta-run conductors

Controller-to-motor conductors for a part-winding motor need not less than 62.5% of full-load current, whereas the line-side branch-circuit conductors use 125% and a wye-start, delta-run motor uses 72%.

NEC 2020 Section 430.22(D)
GFCI protection, dwelling kitchen countertop receptacles (210.8(A)(6))vsAFCI protection, dwelling kitchen branch circuits (210.12(A))

GFCI protection is required for receptacles serving countertop surfaces, and AFCI protection is separately required for all 120-volt, single-phase, 15- and 20-ampere branch circuits supplying outlets in dwelling unit kitchens — both apply.

NEC 2020 Section 210.8(A)(6) and 210.12(A)
Grounded conductor at a separate building/structure fed by a feeder (250.32(B)(1))vsEquipment grounding conductor at that structure

The EGC is run with the supply conductors and connected to the building disconnecting means and grounding electrode(s), while any installed grounded conductor shall NOT be connected to the EGC or to the grounding electrode(s) there.

NEC 2020 Section 250.32(B)(1)
C corporationvsS corporation

Per the NASCLA Summary of Business Legal Structures table, a C corporation allows unlimited shareholders with no personal liability and is taxed at the corporate level plus tax on dividends (double taxation), while an S corporation is limited to 100 shareholders and uses pass-through taxation.

NASCLA Contractors Guide, North Carolina Electrical (14th ed.), Chapter 2 — Summary of Business Legal Structures table

Key Terms

Continuous load NEC 2020 Article 100
Per NEC Article 100, a load where the maximum current is expected to continue for 3 hours or more.
Interrupting rating NEC 2020 Section 110.9
Per 110.9, equipment intended to interrupt current at fault levels must have an interrupting rating at nominal circuit voltage at least equal to the current available at the line terminals of the equipment.
High-leg (higher phase voltage to ground) marking NEC 2020 Section 110.15
Per 110.15, on a 4-wire delta-connected system with the midpoint of one phase winding grounded, the conductor or busbar with the higher phase voltage to ground must be durably and permanently marked orange or by other effective means.
75°C termination rule NEC 2020 Section 110.14(C)(1)(b)
Per 110.14(C)(1)(b), termination provisions of equipment for circuits rated over 100 amperes, or marked for conductors larger than 1 AWG, shall be used only for conductors rated 75°C (167°F) unless the equipment is listed and identified for higher-rated conductors.
Arc-flash label for service equipment 1200 A or more (other than dwelling units) NEC 2020 Section 110.16(B)
Per 110.16(B), the permanent label must list nominal system voltage, available fault current at the service overcurrent devices, the clearing time of those devices based on available fault current, and the date the label was applied — conductor sizes are not required.
Equipment mounting (110.13(A)) NEC 2020 Section 110.13(A)
Electrical equipment shall be firmly secured to the surface on which it is mounted, and wooden plugs driven into holes in masonry, concrete, plaster or similar materials shall not be used.
Multiwire branch circuit disconnect (210.4(B)) NEC 2020 Section 210.4(B)
Each multiwire branch circuit must be provided with a means that will simultaneously disconnect all ungrounded conductors at the point where the branch circuit originates.
Small-appliance branch circuits (210.11(C)(1)) NEC 2020 Section 210.11(C)(1)
Two or more 20-ampere small-appliance branch circuits shall be provided for all receptacle outlets specified in 210.52(B), including dwelling kitchen countertop receptacles, which may not be served by a 15-ampere general-purpose circuit.
Supplemental electrode (250.53(A)(2)) NEC 2020 Section 250.53(A)(2)
A single rod, pipe, or plate electrode must be supplemented by an additional electrode of a type in 250.52(A)(2) through (A)(8), unless the single electrode has a resistance to earth of 25 ohms or less.
Effective ground-fault current path (250.4(A)(5)) NEC 2020 Section 250.4(A)(5)
The Code states the earth shall not be considered as an effective ground-fault current path.
Objectionable current (250.6(B)) NEC 2020 Section 250.6(B)
Where multiple grounding connections result in objectionable current and 250.4(A)(5) or (B)(4) is still met, one permitted alteration is to discontinue one or more — but not all — of such grounding connections.
High-impedance grounded neutral system (250.36) NEC 2020 Section 250.36
A system in which a grounding impedance limits ground-fault current to a low value; permitted for 3-phase AC systems of 480 volts to 1000 volts when all specified conditions are met.
Supply-side bonding jumper for a separately derived system (250.30(A)(2)) NEC 2020 Section 250.30(A)(2)
Where the source of a separately derived system and the first disconnecting means are in separate enclosures, a supply-side bonding jumper must be installed with the circuit conductors from the source enclosure to the first disconnecting means enclosure.
Main bonding jumper screw identification (250.28(B)) NEC 2020 Section 250.28(B)
Where a main bonding jumper or system bonding jumper is a screw only, the screw shall be identified with a green finish that is visible with the screw installed.
Common grounding electrode conductor, wire type (250.30(A)(6)(a)(1)) NEC 2020 Section 250.30(A)(6)(a)(1)
For multiple separately derived systems, a common grounding electrode conductor of the wire type shall not be smaller than 3/0 AWG copper or 250 kcmil aluminum.
Abandoned Class 2, Class 3 and PLTC cable (725.25) NEC 2020 Section 725.25
The accessible portion of abandoned Class 2, Class 3, and PLTC cables shall be removed; cables identified for future use with a tag must have a tag durable enough for the environment involved.

Formulas to Know

Motor branch-circuit conductor minimum ampacity (single continuous-duty motor, 430.22)Ampacity ≥ 125% × motor full-load current; example: 125% × 65 A (50 HP, 480 V, 3-phase) = 81.25 A
Motor feeder conductor minimum ampacity (430.24)Ampacity ≥ (125% × FLC of highest-rated motor) + sum of FLCs of other motors; example: (125% × 65 A) + 40 A = 121.25 A
Nontime-delay fuse maximum, AC polyphase motor (Table 430.52 with 430.52(C)(1) Ex. 1 and 240.6(A))300% × FLC, then next higher standard size permitted if not standard; example: 300% × 65 A = 195 A → 200 A standard fuse
Dual element (time-delay) fuse maximum, AC polyphase motor other than wound-rotor (Table 430.52)175% × FLC before exceptions; example: 65 A × 175% = 113.75 A, then next higher standard rating permitted per 430.52(C)(1) Ex. 1
Separate motor overload device maximum trip setting, service factor 1.15 or greater (430.32(A)(1))Not more than 125% × nameplate FLC; example: 28 A × 125% = 35 A (if insufficient, 430.32(C) permits incremental increases up to 140%)
Controller-to-motor conductors, part-winding continuous-duty motor (NEC 2020, 430.22(D))Ampacity ≥ 62.5% × motor FLC; example: 34 A × 0.625 = 21.25 A
One-family dwelling service conductors, 100–400 A, single-phase 120/240 V (310.12(A))Ampacity permitted to be not less than 83% × service rating; example: 200 A × 0.83 = 166 A
Ampacity adjustment for 10–20 current-carrying conductors in a raceway (Table 310.15(C)(1))Adjusted ampacity = table ampacity × 50%; example: 10 AWG THHN copper 90°C = 40 A → 40 × 0.50 = 20 A
Rooftop ambient temperature adder, raceway/cable in direct sunlight less than 23 mm (7/8 in.) above roof (310.15(B)(2))Ambient for correction factors = outdoor temperature + 33°C (60°F); example: 40°C + 33°C = 73°C (104°F + 60°F = 164°F)
Angle pull box minimum distance to opposite wall (314.28(A)(2))Distance ≥ (6 × trade size of largest raceway) + sum of diameters of all other raceway entries on the same wall; example: (6 × 2) + 1 = 13 in.
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