Exam Cheat Sheet · Quick Reference

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

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 4 Q · 10%
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 specificationsLow-voltage specificationsBonding conductor connectionsBonding/bonding gridTermination
Overcurrent Protection 5 Q · 12%
Location in circuitSizing requirementsCircuit breakersPlug and cartridge fusesEnclosures and locations
Wiring Methods and Terminations 8 Q · 20%
Permitted applications and usagesCharacteristicsConduit and wireway fillPermitted applications and usagesCharacteristicsProtection from damagePermitted usages and ampacity ratingsCharacteristicsMiscellaneous
Boxes and Fittings 2 Q · 5%
General informationSizing requirements
Motors and Control Wiring 5 Q · 12%
General informationBranch circuit and feeder ampacityOverload protectionShort-circuit and ground-fault protectionDisconnects/controllersSizeTypeLocationSeparation of conductors
Load Calculations 2 Q · 5%
Branch circuitsTotal computed loadConductor ampacity requirementsOvercurrent protective device sizingLow-voltage
Appliances, Equipment, and Lighting 4 Q · 10%
Air conditionersResidential, commercial, and industrial equipmentSpace heating equipment and boilers
General 3 Q · 8%
DefinitionsInstallation requirements
Laws, Rules, Basic Business Practices, and Practical Applications 7 Q · 18%
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 EditionLighting and Power Plans; Estimating and General Knowledge

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)
Type AC and Type NM/NMC cable bending radiusvsType MC cable with interlocked-type armor or corrugated sheath

AC cable (320.24) and NM/NMC cable (334.24) require the inner edge of any bend to be not less than five times the cable diameter, while interlocked-armor/corrugated-sheath MC cable (330.24(B)) requires not less than seven times the external diameter of the metallic sheath.

NEC 2020 Section 320.24
Optional dwelling calculation, 220.82(B) (new dwelling)vsExisting dwelling calculation, 220.83(A) (no added A/C or electric space heating)

220.82(B) takes 100% of the first 10 kVA plus 40% of the remainder, while 220.83(A) takes 100% of the first 8 kVA of existing and new load plus 40% of the remainder.

NEC 2020 Section 220.82(B)
Nontime-delay fuse, AC polyphase motor (Table 430.52)vsDual-element (time-delay) fuse, AC polyphase motor (Table 430.52)

Table 430.52 allows a nontime-delay fuse at a maximum of 300% of motor full-load current, while a dual-element time-delay fuse is a maximum of 175% of full-load current (next higher standard size permitted by 430.52(C)(1) Exception No. 1).

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 wye-start, delta-run motor (430.22(C))vsOrdinary single continuous-duty motor branch-circuit conductors (430.22)

Wye-start/delta-run controller-to-motor conductors must be not less than 72% of motor full-load current (58% × 1.25), whereas ordinary motor branch-circuit conductors must be not less than 125% of full-load current.

NEC 2020 Section 430.22(C)
Motor branch-circuit conductor sizing (430.22)vsMotor running overload device setting (430.32(A)(1))

Conductors are sized at not less than 125% of the motor full-load current, while the separate overload device for a motor with a marked service factor of 1.15 or greater is selected to trip at not more than 125% of the motor nameplate full-load current (with incremental increases up to 140% possible under 430.32(C)).

NEC 2020 Section 430.22
Instantaneous trip setting as an arc energy reduction method (240.87(B)(5))vsTemporary adjustment of the instantaneous trip setting during maintenance

An instantaneous trip setting is a permitted arc energy reduction method, but temporarily adjusting the instantaneous trip setting to achieve arc energy reduction is not permitted; zone-selective interlocking, differential relaying, and energy-reducing maintenance switching are permitted.

NEC 2020 Section 240.87(B)
Separate building/structure with no existing grounding electrode (250.32(A))vsGrounded conductor at a separate building/structure fed by a feeder (250.32(B)(1))

250.32(A) requires a grounding electrode system and grounding electrode conductor to be installed where none exists, while 250.32(B)(1) requires an equipment grounding conductor run with the supply conductors and prohibits connecting any installed grounded conductor to the EGC or grounding electrode(s) at that structure.

NEC 2020 Section 250.32(A)
Ampacity adjustment for 7–9 current-carrying conductorsvsAmpacity adjustment for 10–20 current-carrying conductors

Per Table 310.15(C)(1), 7 to 9 current-carrying conductors in a raceway or cable use 70 percent of the table ampacity, while 10 to 20 current-carrying conductors use 50 percent.

NEC 2020 Table 310.15(C)(1)
C CorporationvsS Corporation

Per the NASCLA Summary of Business Legal Structures table, a C corporation allows an unlimited number of shareholders with no personal liability and is taxed at the corporate level with a further 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.
Externally Operable NEC 2020 Article 100 (Definitions, Part I — Externally Operable)
Per NEC Article 100, capable of being operated without exposing the operator to contact with live parts (compare: 'dead front' = without live parts exposed on the operating side; 'enclosed' = surrounded by a case or housing to prevent accidental contact; 'guarded' = covered, shielded or otherwise protected to remove the likelihood of approach to a point of danger).
Interrupting rating (110.9) NEC 2020 Section 110.9
Equipment intended to interrupt current at fault levels shall have an interrupting rating at nominal circuit voltage at least equal to the current that is available at the line terminals of the equipment.
High-leg marking (110.15) NEC 2020 Section 110.15
On a 4-wire, delta-connected system where the midpoint of one phase winding is grounded, the conductor or busbar with the higher phase voltage to ground must be durably and permanently marked with an orange outer finish or by other effective means.
Arc-flash label for service equipment rated 1200 A or more, other than dwelling units (110.16(B)) NEC 2020 Section 110.16(B)
A permanent label must state the nominal system voltage, the available fault current at the service overcurrent protective 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; wooden plugs driven into holes in masonry, concrete, plaster, or similar materials shall not be used.
Small-appliance branch circuits (210.11(C)(1), 210.52(B)) NEC 2020 Section 210.11(C)(1)
Two or more 20-ampere small-appliance branch circuits are required in a dwelling unit for all receptacle outlets specified in 210.52(B), including kitchen countertop receptacles, which therefore may not be served by 15-ampere general-purpose circuits.
Multiwire branch circuit disconnecting means (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.
GFCI protection in other than dwelling units (210.8(B)(2)) NEC 2020 Section 210.8(B)(2)
All 125-volt through 250-volt receptacles supplied by single-phase branch circuits rated 150 volts or less to ground and 50 amperes or less, installed in kitchens or areas with a sink and permanent provisions for food preparation or cooking, require GFCI protection for personnel.
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 provided all specified conditions are met.
Supply-side bonding jumper for separately derived systems (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.
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 those grounding connections.
Effective ground-fault current path (250.4(A)(5)) NEC 2020 Section 250.4(A)(5)
The earth shall not be considered as an effective ground-fault current path.
Plug fuse identification (240.50(C)) NEC 2020 Section 240.50(C)
Plug fuses of 15-ampere and lower rating shall be identified by a hexagonal configuration of the window, cap, or other prominent part to distinguish them from fuses of higher ampere ratings.
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 must be tagged with a tag durable enough for the environment involved.

Formulas to Know

Optional dwelling unit calculation, general load (220.82(B))General calculated load = 100% of the first 10 kVA + 40% of the remainder of the listed loads (not less than).
Existing dwelling unit calculation with no added A/C or electric space heating (220.83(A))Load = 100% of the first 8 kVA of existing and new load + 40% of the remainder.
One-family dwelling service conductor ampacity, 100–400 A, single-phase 120/240 V (310.12(A))Conductors permitted at not less than 83% of the service rating; example: 200 A × 0.83 = 166 amperes (Table 310.12 gives 2/0 AWG copper for a 200 A dwelling service where no adjustment or correction factors are required).
Ampacity adjustment for more than 3 current-carrying conductors (Table 310.15(C)(1))Adjusted ampacity = table ampacity × adjustment factor; 7–9 conductors = 70%, 10–20 conductors = 50%. Example: 12 CCCs of 10 AWG THHN at 90°C (40 A) → 40 × 0.50 = 20 amperes.
Rooftop ambient temperature for raceways/cables in direct sunlight less than 23 mm (7/8 in.) above the roof (310.15(B)(2))Ambient = outdoor temperature + 33°C (60°F) adder; 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 inches.
Motor branch-circuit conductor ampacity, single continuous-duty motor (430.22)Ampacity ≥ 125% of motor full-load current; example: 50 HP, 480 V, 3-phase = 65 A (Table 430.250) → 65 × 1.25 = 81.25 amperes.
Motor feeder conductor ampacity (430.24)Ampacity ≥ (125% × highest-rated motor FLC) + sum of the full-load currents of the other motors; example: (1.25 × 65 A) + 40 A = 121.25 amperes.
Motor branch-circuit short-circuit and ground-fault protection (Table 430.52, 430.52(C)(1) Ex. 1, 240.6(A))Nontime-delay fuse = 300% × FLC (65 A × 3.00 = 195 A → next standard size 200 A); dual-element time-delay fuse = 175% × FLC (65 A × 1.75 = 113.75 A → next higher standard size permitted).
Creditable years of primary experience (21 NCAC 18B .0202(a))Creditable years = total primary experience hours ÷ 2,000 (2,000 hours = one creditable year); example: 11,000 ÷ 2,000 = 5.5 years.
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