General Knowledge
4%of exam
Permits & InspectionsStructural IntegrityEstimating & BidsContractor Liability
General Electrical Knowledge
10%of exam
Ohm's Law3-Phase PowerVoltage DropNEC NavigationTemporary Wiring
Electrical Installation Requirements
10%of exam
Working SpaceEquipment ListingTermination RatingsOver 600V Rules
Services, Feeders & Branch Circuits
10%of exam
Service DisconnectsContinuous LoadsMultiwire CircuitsFeeder Taps
Overcurrent Protection
9%of exam
Standard RatingsSmall Conductor RuleTap RulesRestricted Locations
Grounding & Bonding
10%of exam
Conductors & Cables
8%of exam
THHN vs THWNCable TypesUnderground ConductorsMedium Voltage
Raceways & Boxes
7%of exam
Box FillConduit FillBend LimitsRaceway Selection
Special Occupancies & Equipment
10%of exam
Hazardous LocationsSwimming PoolsHealth CareMobile Homes
Low Voltage & Communications
2%of exam
Class 1/2/3 CircuitsFire AlarmsFiber & PVLow-Voltage Lighting
Lighting & Signs
10%of exam
Closet ClearanceDamp & Wet ZonesIC-Rated FixturesSign Disconnects
Safety
4%of exam
Fall ProtectionTrench SafetyPPE BasicsJob-Site Hazards
Motors & Transformers
6%of exam
Motor FLC SizingMotor DisconnectsTransformer ProtectionIn Sight Rule
Quick Facts
- Exam
- OK Unlimited Journeyman
- Items
- 100 scored
- Time
- 240 min
- Pass
- 70%
- Code
- 2023 NEC
- Format
- Open book
- Retake
- 30 days
- Experience
- 8,000 hours
Permits & Estimating
- Permit puller
- Licensed contractor of record
- Inspection
- Required before energizing work
- Needs analysis
- Scope before estimating a job
- Estimating
- Labor, material, and code compliance
NEC Article Finder
- Need working space depth→110.26(A)(1)(Table by ground volts)
- Need working space width→110.26(A)(2)(30 in or equipment)
- Need working space height→110.26(A)(3)(6.5 ft headroom)
- Check termination temp rating→110.14(C)(60C at or under 100A)
- Confirm equipment install rules→110.3(B)(Follow the listing instructions)
- Need fire-rated penetration rule→300.21(Firestop the opening)
Ohm's & Watt's Law
- E = I x R
- Volts from amps, ohms
- P = E x I
- Watts from volts, amps
- Series R
- Add all resistances
- Parallel R
- Lowest R gets most current
- kWh Cost
- kW x hours x rate
- Voltage Drop
- 3% branch, 5% total note
AC & 3-Phase Basics
- Wye (Y)
- Line = phase x 1.732
- Delta
- Line equals phase voltage
- 208Y/120V
- 120 x 1.732 = 208
- Power Factor
- True power vs apparent
- RMS Voltage
- Effective AC value
- Frequency
- 60 Hz U.S. standard
Listed vs Labeled
Listed
- On a tester's published list
- Includes follow-up inspection
Labeled
- Physical mark on the product
- Meets an identified standard
List entry vs physical mark
Working Space & Listing
- 110.26(A)(1)
- Depth by ground voltage
- 110.26(A)(2)
- Width: 30 in or equipment
- 110.26(A)(3)
- Height: 6.5 ft minimum
- 110.14(C)
- 60C at or under 100A
- 110.3(B)
- Follow the listing instructions
- 300.21
- Firestop fire-rated penetrations
125% Rule
125% covers every continuous load calc
Branch conductor: 210.19OCPD: 210.20(A)Motor conductor: 430.22
Service & Feeder Finder
- How many service disconnects→230.71(1 default, 2-6 in (B))
- Size a continuous load→210.19 & 210.20(125% conductor and OCPD)
- Multiwire circuit disconnect rule→210.4(B)(Simultaneous, all ungrounded conductors)
- Check voltage drop target→210.19 & 215.2 notes(3% branch, 5% total)
- Feeder tap under 10 ft→240.21(B)(1)(Ampacity of the load)
- Feeder tap under 25 ft→240.21(B)(2)(One-third feeder OCPD size)
Services & Disconnects
- 230.71(A)
- One disconnect is the default
- 230.71(B)
- Two to six disconnects allowed
- 210.4(B)
- Simultaneous multiwire disconnect
- 210.19 note
- 3% branch voltage drop
- 215.2 note
- 5% total voltage drop
- 210.19(A)
- 125% for continuous loads
- 210.20(A)
- 125% sizes the breaker too
10-Foot vs 25-Foot Tap
10-ft tap
- Ampacity of the load
- One-tenth feeder OCPD outside
25-ft tap
- One-third feeder OCPD size
- Ends in one breaker
Distance sets the ratio
Overcurrent Rating Finder
- Small copper conductor breaker cap→240.4(D)(15A, 20A, 30A caps)
- No standard size matches→240.4(B)(Next higher, 800A or less)
- Device rated above 800A→240.4(C)(Ampacity must meet device)
- Where breakers are barred→240.24(Bathrooms, closets, stairways)
- Transformer secondary protection case→240.4(F)(2-wire or delta-delta 3-wire)
Overcurrent Standard Ratings
- 240.4(D) 14 AWG
- 15A max breaker
- 240.4(D) 12 AWG
- 20A max breaker
- 240.4(D) 10 AWG
- 30A max breaker
- 240.4(B)
- Next size up, 800A or less
- 240.4(C)
- Above 800A: match ampacity
- 240.6(A)
- Lists standard breaker sizes
- 240.24
- No breakers in bathrooms, closets
Feeder Tap Rules
- 240.21(B)(1)
- 10 ft tap, ampacity of load
- 240.21(B)(2)
- 25 ft tap, one-third feeder OCPD
- 10-ft outside enclosure
- One-tenth feeder OCPD minimum
- 25-ft tap ending
- Single breaker limits the tap
Rod, Ufer, Pool Numbers
8 ft rod, 20 ft Ufer, 4 pool points
Rod: 8 ft longUfer: 20 ft rebarPool bond: 4 points
Grounding vs Bonding
Grounding
- Ties system to earth
- Uses electrode conductor
Bonding
- Joins metal parts together
- Carries fault current back
Earth path vs equipotential
Grounding Table Finder
- Size grounding electrode conductor→Table 250.66(By largest service conductor)
- Size equipment grounding conductor→Table 250.122(By breaker ampere rating)
- Pick a grounding electrode→250.52(A)(Rod, Ufer, ring, or pipe)
- Electrode type that is barred→250.52(B)(Gas pipe or aluminum)
- Bond a swimming pool→680.26(B)(3 ft perimeter, 4 points)
Grounding Electrodes
- 250.52(A)(5)
- Ground rod: 8 ft, 0.625 in
- 250.52(A)(3)
- Ufer: 20 ft rebar or copper
- 250.52(A)(4)
- Ground ring: 20 ft, 2 AWG
- 250.52(A)(1)
- Water pipe: 10 ft, needs supplement
- 250.52(B)
- Gas pipe and aluminum barred
GEC vs EGC
GEC
- Electrode to system
- Sized from Table 250.66
EGC
- Equipment back to source
- Sized from Table 250.122
Different sizing tables entirely
GEC & EGC Sizing
- Table 250.66
- GEC sized by service conductor
- Table 250.122
- EGC sized by breaker rating
- System bonding jumper
- SDS neutral-to-ground bond
- Main bonding jumper
- Service panel neutral bond
- Grounding vs bonding
- Earth path vs equipotential
THWN vs THWN-2
THWN
- 75C rating
- Wet or dry rated
THWN-2
- 90C rating
- Wet and dry both
Dual marking wins ampacity
Conductor & Cable Types
- THHN
- 90C, dry and damp
- THWN
- 75C, wet locations rated
- THWN-2
- 90C, wet and dry
- UF cable
- Direct burial rated
- NM cable
- Dry locations, no burial
- AC cable
- Bonding strip aids grounding path
- MC cable
- Separate wire-type EGC
- MV cable
- 2,001-35,000 volts, Article 311
NM Cable vs UF Cable
NM
- Dry locations only
- Barred from underground burial
UF
- Direct burial rated
- Moisture-resistant sheath
Dry only vs burial rated
Conduit Fill Percentages
One wire 53, two wires 31, three-plus 40
1 conductor = 53%2 conductors = 31%3+ conductors = 40%
Box & Conduit Fill
- 14 AWG box fill
- 2.00 cubic inches each
- 12 AWG box fill
- 2.25 cubic inches each
- 10 AWG box fill
- 2.50 cubic inches each
- 1 conductor fill
- 53% conduit maximum
- 2 conductor fill
- 31% conduit maximum
- 3+ conductor fill
- 40% conduit maximum
- Bend limit
- 360 degrees between pull points
- PVC conduit
- Needs separate wire EGC
Division 1 vs Division 2
Division 1
- Hazard present under normal use
- Continuous or likely exposure
Division 2
- Hazard only if abnormal
- Failure or rupture triggers it
Normal vs abnormal presence
Hazard & Motor Finder
- Flammable gas or vapor present→Class I(Spray booths, fuel areas)
- Combustible dust is present→Class II(Grain or flour handling)
- Ignitible fibers or flyings→Class III(Textile or sawmill areas)
- Size a motor conductor→430.22(125% of table FLC)
- Locate a motor disconnect→430.102(B)(In sight of motor)
Hazardous & Special Occupancies
- Class I
- Flammable gas or vapor
- Class II
- Combustible dust present
- Class III
- Ignitible fibers or flyings
- Division 1
- Hazard present under normal use
- Division 2
- Hazard only if abnormal
- 680.26(B)(2)
- Pool perimeter: 3 ft, 4 points
- 517.13
- Hospital: raceway plus wire EGC
- 550.32
- Mobile home service: 30 ft
- 422.16(B)(5)
- OK furnace cord: 9 ft
Class Circuit Article Shift
Class 1 moved to Article 724 now
Class 1 = Article 724Class 2 and 3 = 725
Low Voltage Circuits
- Article 724
- Class 1 power-limited circuits
- Article 725
- Class 2 and 3 circuits
- Class 2 source
- Listed transformer limits power
- In sight from
- Visible, 50 ft or less
Lighting & Signs Rules
- 410.16(C) surface
- Closet surface fixture: 12 in
- 410.16(C) recessed
- Closet recessed fixture: 6 in
- 410.10(D)
- Bath zone: 3 ft, 8 ft
- 410.116(A)
- Non-IC: 0.5 in from combustibles
- 600.6(A)
- Sign disconnect: three locations allowed
- 410.130(G)(1)
- Ballast swap needs new disconnect
- 410.16(B)
- No open lamps or pendants
OSHA Safety Basics
- 1926.501(b)(1)
- Fall protection at 6 ft
- 1926.451(g)(1)
- Scaffold fall protection at 10 ft
- 1926.652(a)(1)
- Excavation protection at 5 ft
- Competent person
- Inspects trenches daily
- Fall arrest
- Full-body harness required
Motor & Transformer Rules
- 430.22
- Motor conductor: 125% of FLC
- 430.6(A)(1)
- Use table FLC, not nameplate
- 430.102(A)
- Controller disconnect in sight
- 240.4(F)
- Primary device protects some secondaries
- Table 430.250
- Three-phase motor FLC values
Common Traps
Voltage To Ground vs Line
Table 110.26 uses ground volts ≠ Not line-to-line voltage
Informational Note vs Mandatory Rule
3% and 5% drop is advisory ≠ 240.4(D) caps are mandatory
Listed vs Labeled
Listed means on a list ≠ Labeled means a physical mark
Service Disconnect Count
230.71(A) default is one ≠ 230.71(B) allows two to six
Class 1 vs Class 2 and 3
Class 1 now sits in 724 ≠ Class 2/3 stays at 725
OK GFCI Amendment
Oklahoma exempts lighting and HVAC ≠ Base rule covers all outlets
Last Minute
- 1.Bound 2023 NEC only, no handbook
- 2.Continuous loads size at 125%
- 3.GEC size: use Table 250.66
- 4.EGC size: use Table 250.122
- 5.Ground rod: 8 ft, 0.625 in
- 6.Conduit fill: 3+ wires max 40%
- 7.Raceway bends: max 360° total
- 8.OSHA trenches: 5 ft needs protection
- 9.OSHA falls: 6 ft general trigger
- 10.Scaffold fall trigger: 10 ft high
- 11.Class 1: Article 724, not 725
- 12.OK allows temp cord-connected gas furnace
- 13.OK GFCI rule skips lighting, HVAC
- 14.Service disconnects: 1 default, 6 max
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