Exam Cheat Sheet · Quick Reference

South Carolina Electrician

South 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
80
Passing score
70%
Exam time
300 min
Administered by
PSI Services Contractor
Format
Reference materials allowed

South Carolina State Portion 80 questions

General Electrical Knowledge 9 Q · 11%
Ohm's law and DC circuit calculationsAC circuit theory: impedance, reactance, and power factorElectrical units and fundamental quantities (voltage, current, resistance, capacitance, inductance)Three-phase and single-phase power relationshipsNEC definitions and code terminologyElectrical testing instruments and measurement methodsHarmonics: causes, effects, and mitigationConductor properties, types, and insulation classifications
Service, Feeders, and Branch Circuits 9 Q · 11%
Branch-circuit ratings, types, and voltage limitationsGFCI and AFCI protection requirements by location and occupancyService conductor clearances, sizing, and installation requirementsFeeder and service load calculations including demand factorsGrounding and bonding of services, feeders, and branch circuitsOvercurrent protection of conductors and standard ampere ratingsMultiwire branch circuit requirements and disconnecting meansConductor identification for grounded, equipment grounding, and ungrounded conductors
Grounding and Bonding 9 Q · 11%
Grounding electrode system and types of grounding electrodesEquipment grounding conductors and effective ground-fault current pathMain bonding jumper and system bonding jumper requirementsGrounding of service-supplied AC systemsGrounding of separately derived AC systemsBonding of electrical equipment and conductive materialsSurge-protective device (SPD) grounding and bonding connectionsPermitted and prohibited connection methods for grounding and bonding conductors
Conductors and Cables 9 Q · 11%
Conductor insulation types, temperature ratings, and applications (THHN, THWN, RHW, XHHW, etc.)Ampacity determination and adjustment factors for conductors and cablesConductor sizing, AWG/kcmil designations, and minimum size requirementsConductor identification and marking requirementsNonmetallic-sheathed cable (Types NM and NMC) uses, installation, and supportMetal-clad cable (Type MC) and armored cable (Type AC) uses and installationUnderground cable types (UF, USE, direct burial) and installation requirementsSpecialty cable types (MI, TC, SE, medium voltage MV) uses and construction
Raceways and Boxes 9 Q · 11%
Conduit fill calculations and conductor fill percentages (Chapter 9 Table 1 and Annex C)Securing and supporting requirements for each raceway type (spacing and fastening distances)Uses permitted and uses not permitted for each raceway type by location and environmentBend requirements — number per run, minimum radius, and field-bending methodsBox fill calculations for outlet, device, and junction boxes (Article 314)Pull box and junction box sizing for conductors 4 AWG and larger (straight and angle pulls)Cabinet, cutout box, and meter socket enclosure installation requirements (Article 312)Grounding and bonding of metallic raceways and boxes
Special Occupancies and Equipment 2 Q · 2%
Hazardous location classification — Class I, II, and III Divisions and ZonesWiring methods and sealing requirements in hazardous locationsHealth care facility wiring — patient care spaces, grounding, and essential electrical systemsSwimming pools, fountains, and similar installations — GFCI, bonding, and clearancesSpecial occupancies — commercial garages, aircraft hangars, motor fuel dispensing, and bulk storage plantsEmergency systems — power sources, wiring, and transfer equipmentElevators, escalators, and similar equipment — wiring, disconnects, and GFCI requirementsRecreational vehicles, mobile homes, and marinas — wiring and power supply requirements
Electrical Power 7 Q · 9%
Overcurrent protection devices and ratings (fuses, circuit breakers) for conductors and equipmentGrounding and bonding requirements for AC systems and service equipmentElectrical services: overhead and underground conductor clearances and installation requirementsTransformers: types, ratings, overcurrent protection, and installation requirementsGenerators: ratings, overcurrent protection, conductor ampacity, and marking requirementsEmergency, legally required standby, and optional standby power systemsElectrical power distribution systems: series, parallel, and three-phase circuit configurationsOvervoltage and surge protection devices (SPDs and surge arresters)
Motors 7 Q · 9%
Motor branch-circuit conductor sizing and ampacity requirementsMotor overload protection (types, ratings, and selection)Motor branch-circuit short-circuit and ground-fault protective device ratings (Table 430.52)Motor disconnecting means requirementsMotor controller marking and ratingsMotor nameplate markings and locked-rotor code lettersAdjustable-speed drive systems for motorsHermetic refrigerant motor-compressor circuit requirements (Article 440)
Low Voltage 2 Q · 2%
Class 1, Class 2, and Class 3 circuit classifications and power source requirementsWiring methods and cable types for Class 2 and Class 3 circuits (CL2, CL3, PLTC, plenum, riser)Separation requirements between low-voltage circuits and power/light conductorsFire alarm circuit types: non-power-limited (NPLFA) and power-limited (PLFA) wiring and cable requirementsLow-voltage lighting systems (Article 411): voltage limits, isolation, and installation requirementsLow-voltage suspended ceiling power distribution systems (Article 393): listing, connectors, and overcurrent protectionInstrumentation Tray Cable (Type ITC): permitted uses, ampacity, and overcurrent protectionCircuits operating at less than 50 volts (Article 720): conductor sizing, receptacle ratings, and workmanship
Lighting 5 Q · 6%
Luminaire installation requirements by location (wet, damp, corrosive, closets, bathrooms, show windows)Luminaire types and classification (incandescent, fluorescent, HID, LED, low-voltage)Luminaire support and mounting methods (outlet boxes, suspended ceilings, poles, trees)Grounding of luminaires and lighting equipmentRecessed luminaire requirements (clearances, thermal protection, Type IC vs. non-IC, wiring)Lampholders and lampholder installation requirementsBallasts and auxiliary equipment for electric-discharge and LED luminaires (thermal protection, disconnecting means)Branch-circuit voltage limitations and wiring requirements for lighting loads
Illuminated Signs 2 Q · 2%
Listing and labeling requirements for signs, outline lighting, and retrofit kitsRequired branch circuits and ratings for sign installationsDisconnecting means location and requirements for signs and outline lightingGrounding and bonding of sign equipment and metal partsEnclosure requirements for signs and outline lighting systemsNeon secondary-circuit wiring requirements (1000V or less and over 1000V)Transformers, electronic power supplies, and Class 2 power sources for signsMarking requirements for signs, retrofit kits, and retrofitted illumination systems
Fire Detection and Alarm Systems 2 Q · 2%
Types of initiating devices (manual fire alarm boxes, heat detectors, smoke detectors, flame detectors, supervisory switches)Heat detector classification, temperature ratings, and spacing requirementsSmoke detector placement, spacing, and coverage concepts (total, partial, selective, nonrequired)Notification appliance requirements (audible, visual, and tactile) including sound pressure levels and temporal patternsFire alarm circuit types and pathway class designations (Class A, B, N, X) under NEC Article 760 and NFPA 72 Chapter 12Power supply requirements and wiring methods for non-power-limited and power-limited fire alarm circuitsInspection, testing, and maintenance requirements and frequencies for fire alarm system componentsSupervising station alarm systems (central station, proprietary, and remote station) and signal transmission requirements
Safety Information 8 Q · 10%
Electrical hazard recognition and guarding of live parts (OSHA 1926 Subpart K)Ground-fault circuit interrupter (GFCI) and assured equipment grounding conductor program requirementsPersonal protective equipment selection, use, and employer payment obligationsElectrical protective equipment classes and testing (rubber insulating gloves, blankets, sleeves)Lockout/tagout and deenergizing lines and equipment for employee protectionConfined space entry procedures, atmospheric testing, and permit requirementsSC 811 excavator responsibilities, locate request procedures, and underground facility damage preventionFirst aid, medical services, and emergency response requirements on construction sites

Key Distinctions

OverloadvsShort Circuit / Ground Fault

An overload is excess current beyond normal full-load rating that causes damage when it persists; a short circuit or ground fault is NOT classified as an overload and requires different protective measures.

NEC Handbook, Article 100 — Definitions, Overload
Surge ArrestervsSPD (Surge-Protective Device)

A surge arrester limits surge voltages by discharging or bypassing surge current AND prevents continued flow of follow current with repeat capability, while an SPD limits transient voltages by diverting or limiting surge current without the follow-current prevention function.

NEC Handbook, Article 100 — Definitions, Surge Arrester
Ammeter (M1)vsVoltmeter (M2)

An ammeter is connected in series with very low internal resistance to measure current flow, while a voltmeter is connected in parallel with very high internal resistance to measure potential difference across a component.

15-ampere plug fusevsHigher-rated plug fuse

Plug fuses of 15-ampere and lower rating are identified by a hexagonal configuration of the window or cap, while higher-ampere-rated fuses do not use the hexagonal shape.

NEC 240.50(C)
Single grounding electrode (rod) — resistance ≤ 25 ΩvsSingle grounding electrode (rod) — resistance > 25 Ω

If a single ground rod measures 25 ohms or less resistance to earth, no supplemental electrode is required; if it exceeds 25 ohms, a supplemental electrode must be installed.

NEC, Section 250.53(A)(2)
Continuous LoadvsNon-Continuous Load

A continuous load is one where maximum current is expected to persist for 3 hours or more, while a non-continuous load does not sustain maximum current for that duration.

NEC Article 100
Feeder disconnect for ≤ two 2-wire branch circuitsvsFeeder disconnect for one-family dwelling

A structure served by no more than two 2-wire branch circuits requires a minimum 30-ampere disconnecting means, while a one-family dwelling feeder disconnect must be rated at least 100 amperes, 3-wire.

NEC 225.39(B)
NEC Chapter 8 (Communications Systems)vsNEC Chapters 1–7

Chapters 1–7 contain general and specific installation rules that apply broadly, while Chapter 8 covers communications systems and is NOT subject to Chapters 1–7 except where specifically referenced in Chapter 8.

NEC 90.3
GFCI ProtectionvsAFCI Protection

GFCI protection guards against ground-fault shock hazards at locations like kitchen countertops and commercial kitchen sinks, while AFCI protection guards against arc-fault fire hazards on 120-volt, single-phase, 15- and 20-ampere dwelling unit branch circuits.

NEC 210.8(A)(6) and 210.12(A)
75°C conductor termination rating (circuits > 100 A)vsHigher temperature conductor termination rating

Terminations on equipment rated over 100 amperes must default to 75°C-rated conductors; higher temperature ratings are permitted only when the equipment is listed and identified for that use, and ampacity still may not exceed the 75°C value.

NEC 110.14(C)(1)(b)
Optional dwelling load calculation (NEC 220.82) — first 10 kVAvsOptional dwelling load calculation (NEC 220.82) — remainder

Under the optional method, the first 10 kVA of general loads is calculated at 100%, and all load beyond 10 kVA is calculated at only 40%.

NEC 220.82(B)
Fixed electric space-heating load calculationvsCommercial kitchen equipment demand factor

Fixed electric space-heating loads must be calculated at 100% of total connected load with no demand factor reduction, while commercial kitchen equipment with thermostatic controls (6 or more units) may use a 65% demand factor.

NEC 220.51

Key Terms

Continuous Load (NEC Article 100) NEC Article 100
A load where the maximum current is expected to continue for 3 hours or more.
Interrupting Rating Requirement (NEC 110.9) NEC 110.9
Equipment intended to interrupt current at fault levels must have an interrupting rating at nominal circuit voltage at least equal to the available fault current at its line terminals.
High-Leg (Orange) Conductor (NEC 110.15) NEC 110.15
On a 4-wire delta system where the midpoint of one phase is grounded, the conductor with the higher phase voltage to ground must be permanently marked orange.
Arc-Flash Label Requirements — 1200 A Service (NEC 110.16(B)) NEC 110.16(B)
Permanent labels on service equipment rated 1200 A or more (other than dwelling units) must show nominal system voltage, available fault current, clearing time of overcurrent protective devices, and the date applied — conductor sizes are NOT required.
Informational Notes — Enforceability (NEC 90.5(C)) NEC 90.5(C)
Explanatory informational notes in the NEC are included for informational purposes only and are NOT enforceable as Code requirements.
Overhead Conductor Clearance — Truck Traffic Areas (NEC 225.18(4)) NEC 225.18(4)
Open conductors of 1000 V or less over public streets, alleys, roads, and areas subject to truck traffic must maintain a minimum clearance of 5.5 m (18 ft).
Vegetation Support Prohibition (NEC 225.26) NEC 225.26
Trees and other vegetation shall NOT be used to support overhead conductor spans for outside branch circuits and feeders.
High-Impedance Grounded Neutral System (NEC 250.36) NEC 250.36
A 3-phase AC system where a grounding impedance limits ground-fault current to a low value; permitted only for systems in the 480-volt to 1000-volt range.
Solder-Only Connections — Prohibition (NEC 250.8(B)) NEC 250.8(A) and 250.8(B)
Connection devices or fittings that depend solely on solder are NOT permitted for connecting grounding electrode conductors, equipment grounding conductors, or bonding jumpers.
Wooden Plugs — Prohibition (NEC 110.13(A)) NEC 110.13(A)
Wooden plugs driven into holes in masonry, concrete, plaster, or similar materials shall NOT be used for mounting electrical equipment.
Surge Arrester NEC Handbook, Article 100 — Definitions, Surge Arrester
A protective device that limits surge voltages by discharging or bypassing surge current, prevents continued flow of follow current, and is capable of repeating these functions.
Overload NEC Handbook, Article 100 — Definitions, Overload
Operation of equipment in excess of normal full-load rating that, when it persists for a sufficient length of time, would cause damage or dangerous overheating; short circuits and ground faults are NOT overloads.
Single Ground Rod — Supplemental Electrode Rule (NEC 250.53(A)(2)) NEC, Section 250.53(A)(2)
A single rod, pipe, or plate electrode must be supplemented by an additional electrode unless the single electrode measures 25 ohms or less resistance to earth.
NFPA 72 SLC Single-Fault Zone Limitation (NFPA 72 Section 23.6.1) NFPA 72 2019 Handbook, Section 23.6.1
A single fault on a signaling line circuit connected to addressable devices shall not cause the loss of devices in more than one zone.

Formulas to Know

Ohm's Law — CurrentI (A) = E (V) ÷ R (Ω)
Ohm's Law — VoltageE (V) = I (A) × R (Ω)
Ohm's Law — ResistanceR (Ω) = E (V) ÷ I (A)
Total Resistance — Series CircuitR_total = R1 + R2 + R3 + ...
Total Resistance — Parallel Circuit (two resistors)R_total = (R1 × R2) ÷ (R1 + R2)
Power (Watts)P (W) = E (V) × I (A)
Optional Dwelling Unit Load — General Load (NEC 220.82(B))Load = 100% × (first 10 kVA) + 40% × (remainder of total listed load)
Existing Dwelling Additional Load — No A/C or Heat (NEC 220.83(A))Load = 100% × (first 8 kVA) + 40% × (remainder of existing + new load)
Small-Appliance Circuit Load per Circuit (NEC 220.52(A))Load per 2-wire small-appliance branch circuit = 1,500 VA
Commercial Kitchen Equipment Demand (NEC Table 220.56)Feeder load = Total kitchen equipment nameplate load × demand factor (65% for 6 or more units)
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