NEC 2023 Exam Prep
Checklist

"Readily accessible," "dwelling unit," "branch circuit vs. feeder" — the definitions that settle field arguments and determine which GFCI, AFCI, and load calculation rules apply to a given space.

• §100I can define "readily accessible" vs. "accessible" and explain why the distinction matters for panel placement.
• §100I know the difference between a branch circuit, a feeder, and a service — and which GFCI/AFCI rules apply to each.
• §100I can identify a "dwelling unit" and explain how the ADU classification changes applicable code sections.
• §100I understand the definition of "listed" vs. "labeled" and how it affects equipment selection on the exam.
• §100I can define "qualified person" and explain its significance to OSHA and NFPA 70E overlap questions.
• §100I can distinguish "grounded" from "grounding" and explain why the difference matters for Art. 250 bonding questions.

Three dimensions (depth, width, headroom), the Conditions 1/2/3 system for depth requirements, and why storage is still the most-cited §110.26 violation years after installation.

• §110.26(A)I know the three minimum working space dimensions (depth, width, headroom) for 120–250V equipment.
• §110.26(A)(1)I can identify Conditions 1, 2, and 3 and select the correct depth from Table 110.26(A)(1).
• §110.26(A)(2)I know the minimum width rule — widest equipment or 30 inches, whichever is greater.
• §110.26(A)(3)I know the 6.5-ft minimum headroom requirement and the exception for service under 200A.
• §110.26(C)I understand the dedicated electrical space requirements above and below a panelboard (extends 6 ft above or to structural ceiling).
• §110.26(E)I know when a second egress from an electrical room is required (over 1,200A and longer than 6 ft workspace).

Where GFCI protection now applies under §210.8 — including fridge circuits — AFCI room requirements under §210.12, and the field shortcut for keeping them straight on rough-in day.

• §210.8(A)I can list all dwelling unit locations requiring GFCI protection including kitchen, bathrooms, garages, outdoors, unfinished basements, and boathouses.
• §210.8(A)(10)I know that the 2023 NEC now requires GFCI protection for 125V receptacles serving refrigerators in dwelling units.
• §210.12(A)I can list the rooms requiring AFCI protection in a dwelling unit (all 120V, 15/20A circuits) and know what's exempt.
• §210.11(C)(1)I know the required number of small appliance circuits in a kitchen (minimum 2) and what they can serve.
• §210.52I can apply the receptacle spacing rule — no point on a wall should be more than 6 ft from a receptacle.
• §210.19I understand minimum conductor size for branch circuits and how to match wire to breaker rating.

Standard vs. optional method, demand factors from Table 220.42, the 2023 neutral demand clarification, and why adding up every nameplate value is the fastest way to oversize a service.

• §220.12I can calculate general lighting load at 3 VA/sq ft for dwelling units and apply it to a service calculation.
• Table 220.42I know the demand factors for lighting loads — 100% of the first 3,000 VA, 35% of the next 117,000 VA.
• §220.54I can apply the dryer demand factor — 5,000W or the nameplate rating, whichever is larger, then Table 220.54 for multiple units.
• §220.55I can apply Table 220.55 demand factors for electric ranges and cooking equipment.
• §220.87I know the optional method for existing dwelling services and when it can be used vs. the standard method.
• §220.61I can calculate the neutral load and know which loads are counted at 100% vs. 70% (over 200A).

§230.85 firefighter disconnect requirements, §230.67 SPD now mandatory on dwelling unit services, and why a panel upgrade alone triggers the surge protection requirement.

• §230.71I know the maximum number of service disconnecting means allowed (6 switches or circuit breakers).
• §230.85I can describe the 2023 NEC §230.85 emergency disconnect requirement — exterior, marked, accessible to first responders.
• §230.67I know that SPD (Type 1 or 2) is now required on all new dwelling unit services under 2023 NEC.
• §230.24I can apply the clearance rules for service conductors (10 ft over grade, 12 ft over residential driveways, 18 ft over public roads).
• §230.79I know the minimum service disconnect ampere ratings — 60A for 1-family, 100A for ≥6 circuits or electric range/dryer.
• §230.9I understand service conductor clearances from windows, doors, and porches — 3 ft rule for openings.

When you can round up to the next standard breaker size — and when §240.4(D) hard-caps small conductors. The rule that catches 12 AWG on 25-amp breakers every time.

• §240.4(B)I know when rounding up to the next standard breaker size is allowed — conductor ampacity not corresponding to a standard size.
• §240.4(D)I know the small conductor rule hard caps: 14 AWG = 15A max, 12 AWG = 20A max, 10 AWG = 30A max. No rounding up.
• §240.6(A)I can recite the standard ampere ratings for fuses and circuit breakers from 15A through 800A.
• §240.21I understand tap conductor rules — 10-ft tap, 25-ft tap, and the feeder tap exceptions with termination requirements.
• §240.24I know where overcurrent devices must be readily accessible and the exceptions (for dwelling unit lighting circuits).
• §240.85I understand application of Series-rated systems and the marking/labeling requirements when using them.

The real difference between grounding and bonding, the concrete-encased electrode (Ufer) requirement under §250.50, and the most common bonding mistakes that cause failed finals.

• §250.24I can explain why the neutral is grounded at the service and why it must NOT be re-grounded at sub-panels (separately derived systems excepted).
• §250.50I know that all available grounding electrodes must be bonded together to form the grounding electrode system — including Ufer, water pipe, rod, plate.
• §250.52(A)(3)I can describe the concrete-encased electrode (Ufer) requirements — 20 ft of ½-inch rebar or 4 AWG copper in footing.
• Table 250.66I can size the grounding electrode conductor (GEC) from Table 250.66 based on service entrance conductor size.
• §250.122I can size the equipment grounding conductor (EGC) from Table 250.122 based on the overcurrent device rating.
• §250.104I know the bonding requirements for metal water and gas piping within 5 ft of where they enter the building.

Nail-plate requirements at framing members under §300.4, Table 300.5 burial depths and the variables that change the number, plus riser protection at conduit transitions to exposed vertical runs.

• §300.4(A)I know when a nail plate is required — wiring within 1.25 inches of the edge of a framing member, 1/16-inch thick steel.
• Table 300.5I can look up minimum burial depths for UF cable, RMC, IMC, and PVC conduit under different surface types.
• §300.5(D)I know when underground conductors rising from grade require protection and how high that protection must extend (8 ft above grade).
• §300.11I know that wiring methods cannot be supported by or attached to ceiling grid support wires — independent support is required.
• §300.14I know the minimum free conductor length at each outlet, junction, or switch box — 6 inches from the point of entry, 3 inches outside the box.
• §300.22I understand wiring methods permitted in plenums and ducts — and why only listed plenum-rated cable or conduit may be used.

Why THHN on a 90°C column is usually irrelevant, the four-step sizing process (base ampacity → temp correction → bundling → terminal rating), and LA attic heat adders for exposed solar conduit.

• Table 310.16I can look up the 60°C and 75°C ampacity values for common wire sizes (14, 12, 10, 8, 6, 4, 3, 2, 1, 1/0, 2/0, 3/0, 4/0 AWG).
• §110.14(C)I know the terminal temperature rule — most equipment terminals are rated at 60°C or 75°C, so the conductor must be sized to the terminal rating, not the wire insulation rating.
• §310.15(B)I can apply the ambient temperature correction factors from Table 310.15(B)(1) for installations in locations above 86°F (30°C).
• §310.15(C)I can apply the bundling/conduit fill adjustment factors from Table 310.15(C)(1) when more than 3 current-carrying conductors are bundled.
• §310.15(B)I know the four-step ampacity calculation sequence: (1) base ampacity → (2) temp correction → (3) bundling adjustment → (4) apply terminal limit.
• §310.10(H)I know when aluminum conductors are permitted and the minimum size for aluminum branch circuits (12 AWG, terminated with CU/AL-rated devices).

How to count conductors correctly, the 2023 update to ground wire volume allowances, device allowances, and why smart switches are pushing old boxes over the fill limit.

• Table 314.16(A)I can look up the maximum number of conductors allowed in standard metal boxes (e.g., 4×4, 4×2, 3×2 device boxes).
• §314.16(B)I know the counting rules: each conductor entering counts 1; a looped conductor counts 1 if unbroken; EGCs count as one total regardless of quantity; a device counts 2.
• §314.16(B)(1)I can calculate the fill allowance in cubic inches — conductor volume from Table 314.16(B) × number of conductors counted.
• §314.16(B)(4)I know the 2023 NEC change — each EGC now requires individual volume credit (not grouped) when they differ in size.
• §314.27I know the box support requirements for fan-rated boxes vs. standard fixture boxes (rated for 35 lb or 70 lb fan support).
• §314.23I can identify valid box support methods — studs, joists, bar hangers, and the independent support requirement for boxes over 100 cubic inches.

Support spacing, the §334.12 uses-not-permitted list, stapling damage from over-driven staples, and local amendment differences across LA County jurisdictions for multifamily construction.

• §334.10I know where NM cable is permitted — one- and two-family dwellings, and multi-family dwellings up to the height of wood-frame construction.
• §334.12I can list the uses not permitted: in commercial garages, theaters, motion picture studios, storage battery rooms, hazardous locations, and embedded in concrete.
• §334.15(B)I know the support requirements — every 4.5 ft and within 12 inches of each box or fitting (NM cable).
• §334.17I know the through-framing protection requirements — bushings required at metallic framing, anti-short bushings at metallic knockouts.
• §334.30I can identify when flat cable must be stapled flat (not on edge) and the exceptions for bends and where the cable enters boxes.
• §334.80I know the ampacity limitation — NM cable must use 60°C column from Table 310.16 regardless of insulation type.

§408.4(A) circuit directory accuracy as a common final-delay violation, back-fed breaker hold-down clips on solar retrofits, and tandem breaker slot restrictions from the listing label.

• §408.4(A)I know that every circuit in a panelboard must be legibly identified with the load it serves and the identification must be handwritten or mechanically printed — pencil is not acceptable.
• §408.36I know the overcurrent protection requirements for panelboards — the main breaker must protect the bus, or all circuits must be protected individually (split-bus rule).
• §408.36(D)I know that back-fed breakers used as service disconnects require a hold-down clip — the breaker is not removable by normal plug-in motion.
• §408.54I understand that tandem (double-pole single-width) breakers are only permitted in slots designated for them by the panel's listing label.
• §408.41I know that panelboard grounded conductors must be connected to an individual terminal — no double-tapping on the neutral bar.
• §408.55I know the wire-bending space requirements inside panelboards and how to verify they are satisfied from the listing label or Table 312.6.

Why conductor sizing, branch-circuit protection, overload protection, and disconnect sizing each use different calculations — and why nameplate current is only correct for one of them.

• Tables 430.247–250I know to use the FLA table value (not the nameplate) for conductor sizing, branch-circuit protection, and disconnects — nameplate FLA is used only for overload protection.
• §430.22I can size motor branch-circuit conductors at 125% of FLA from Table 430.250 (not the nameplate).
• §430.52I know the branch-circuit short-circuit and ground-fault protection multipliers: 250% for inverse-time breakers, 300% for instantaneous-trip breakers (up to 400% if needed for starting).
• §430.32I know the overload protection sizing rules — 115% of motor nameplate FLA for motors marked "SF 1.15 or greater" or "40°C rise"; 125% for all others.
• §430.109I know the motor disconnect types permitted and the minimum ampere rating (115% of nameplate FLA for horsepower-rated switches).
• §430.102I know the disconnect location rules — in sight from the motor and within sight from the controller, with specific exceptions for torque motors and multi-motor equipment.