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NEC Code Reference

Plain-English guides to the NEC articles NJ electricians and homeowners deal with every day. Written by Michael Malfettone, a licensed third-generation NJ master electrician (Malfettone Electric LLC, Hudson County, family-owned since 1977). Each guide is a summary — never a verbatim NEC reproduction. For the authoritative text consult NFPA 70.

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Article 100

NEC Article 100 — The Definitions Every NJ Electrician Should Memorize

NEC Article 100 defines the terms used throughout the entire code. Branch circuit, feeder, service, dwelling unit, qualified person, readily accessible — these definitions decide compliance interpretations on every NJ permit review.

Article 110

General requirements — working space, identification, and the rules every install must follow.

NEC Article 110 — Working Space, Identification, and the General Rules NJ Inspectors Cite Most

NEC Article 110 sets the universal rules: working space around equipment (110.26), arc-flash labeling, identification of disconnects, and dedicated equipment space. The most-cited article on NJ residential rough-in inspections.

Article 210

Branch circuits — required AFCI/GFCI areas, dwelling-unit circuit minimums, receptacle spacing.

NEC Article 210 — Branch Circuits, AFCI, GFCI, and What Goes on a Dedicated Circuit

NEC 210 sets the rules for branch circuits in residential occupancies: required AFCI areas (210.12), required GFCI locations (210.8), small-appliance branch circuits, and which loads need their own dedicated circuit.

Article 215

NEC 215 — Feeder Conductor Sizing and the Voltage Drop Recommendation

NEC 215 governs feeders — the conductors between service equipment and a sub-panel's main breaker. Continuous-load multipliers, voltage drop recommendation, and how feeder sizing differs from branch-circuit sizing.

Article 220

Load calculations — sizing the service to the building.

NEC Article 220 Load Calculations: Standard vs Optional Method

Plain-English walkthrough of how to calculate a residential service load using the Standard method (Part III) and the Optional method (Part IV), with practical NJ examples.

Article 230

Services — utility connection through main disconnect.

NEC Article 230 — Service Conductors, Service Equipment, and the Six-Disconnect Rule

NEC 230 governs everything from the utility connection to the main breaker: service-entrance conductor sizing, service rating, the six-disconnect rule, and where the service disconnect must be located.

Article 240

Overcurrent protection — breakers, fuses, and the small-conductor rule.

NEC 240.4(D) — The Small Conductor Rule (14, 12, 10 AWG breaker limits)

The NEC 240.4(D) "small conductor rule" caps the maximum breaker amperage on 14, 12, and 10 AWG conductors regardless of ampacity tables. Critical for residential branch circuits.

NEC Article 240 — Overcurrent Protection: Beyond the Small-Conductor Rule

NEC 240 covers overcurrent protection broadly: standard breaker amperages (240.6), where overcurrent must be located (240.21), tap rules, and protection for branch-circuit conductors.

Article 250

Grounding and bonding — ground rods, water-main bonds, equipment grounding.

NEC Article 250 — Grounding and Bonding for NJ Residential Services

How NJ residential services are grounded and bonded per NEC 250: ground rods, water main bonds, GEC sizing, and the neutral-to-ground bond at the service disconnect.

NEC 250.122 — Sizing the Equipment Grounding Conductor (EGC) by Breaker Amperage

NEC 250.122 sizes the equipment grounding conductor (EGC) based on the breaker rating of the circuit. Different from the GEC sized by 250.66. Critical for sub-panel feeders and EV charger circuits.

NEC 250.32 / 250.30

NEC 250.30 / 250.32 — Separately Derived Systems and Bonding at the Generator

A "separately derived system" is a power source (generator, transformer) whose neutral is NOT directly connected to any other source. NEC 250.30 governs how to bond and ground them. Critical for switched-neutral vs solid-neutral generator ATS decisions.

Article 300

NEC 300.4 — Protection Against Physical Damage (Bored Holes, Notching, Stud Plates)

NEC 300.4 sets the rules for protecting cables from physical damage during framing. Bored holes need clearance from stud edges; cables run through notches need steel nail plates. The rule that catches every rough framer who tried to "help" the electrician.

Article 310

Conductors — ampacity, temperature ratings, insulation types.

NEC Article 310 — Conductor Ampacity, Temperature Ratings, and the 75 °C / 90 °C Rule

NEC 310 defines conductor ampacity (Table 310.16), temperature ratings, and the rule that limits ampacity to the lowest-rated termination. Why 75 °C is what really matters in residential.

Article 312

NEC 312 — Cabinets, Cutout Boxes, and Meter Sockets

NEC 312 covers the enclosures that hold panels, disconnects, and meter sockets. Wire bending space, cabinet damp/wet location ratings, and the conductor fill rules that apply to gutter spaces inside the cabinet.

Article 314

Outlet boxes — fill calculations and box sizing.

NEC Article 314 — Outlet Box Fill Calculations (How Many Conductors Fit in a 4×4 Box?)

NEC 314.16 limits how many conductors can fit in an outlet box based on internal volume. Each conductor counts as one, plus extras for clamps, devices, and ground conductors.

Article 334

NM cable (Romex) — where it's allowed and where conduit is required instead.

NEC Article 334 — NM Cable (Romex): Where It's Allowed and Where Hudson County Says No

NEC 334 governs NM-B cable (Romex). Allowed in dwelling-unit dry locations. NOT allowed in commercial, exposed-to-physical-damage, wet locations. Hudson County urban municipalities often require conduit even in residential.

Article 348

Flexible metal conduit — final connections to motors and HVAC.

NEC Article 348 — Flexible Metal Conduit (FMC) for HVAC, Motors, and Final Connections

NEC 348 governs FMC ("greenfield" or "flex") used for final connections to motors, HVAC equipment, and luminaires where rigid conduit can't flex. Length limits, ground-path rules.

Article 358

EMT — the urban-NJ default wiring method.

NEC Article 358 — EMT (Electrical Metallic Tubing): The NJ Urban Default

NEC 358 governs EMT — thin-wall metal conduit. The default wiring method in Hudson County urban municipalities (Jersey City, Hoboken, Bayonne) where Romex is locally restricted. Bend rules, support, and where it's not allowed.

Article 406

Receptacles — TR, WR, in-use covers, height and spacing.

NEC Article 406 — Receptacles: Tamper-Resistant, Weather-Resistant, and the In-Use Cover Rule

NEC 406 governs receptacle installation: tamper-resistant in dwelling units (406.12), weather-resistant outdoors (406.9), in-use covers, GFCI on countertops, and the height/spacing rules.

Article 408

Panelboards — working space, schedule, dead-front cover.

NEC Article 408 — Panelboard Requirements (Working Space, Labels, Schedule)

Article 408 governs panelboards: working space (110.26), required circuit directory, dead-front cover, and the panel schedule that must accompany every NJ permit submission.

Article 410

NEC 410 — Luminaires (Lighting Fixtures): IC vs Non-IC, Damp/Wet Locations, and Box Support

NEC 410 governs luminaires — what we usually call light fixtures. IC vs non-IC recessed cans for insulation contact, damp/wet location ratings for bathrooms and outdoor, support requirements for ceiling fans, and the closet-luminaire clearance rule.

Article 422

Appliances — disconnects, dedicated circuits, dishwasher GFCI.

NEC Article 422 — Appliances: Dedicated Circuits, Disconnects, and the Dishwasher GFCI Rule

NEC 422 governs appliances. Dishwasher and disposal need dedicated circuits, dishwasher needs GFCI per the 2020 NEC, and every appliance needs a way to disconnect for service.

Article 424

NEC 424 — Fixed Electric Space Heating: Baseboards, Heat Pumps, and the 125% Continuous-Load Rule

NEC 424 covers fixed electric space heating equipment — baseboards, electric furnaces, mini-split heat strips. All electric heat is a continuous load and must be sized at 125%. Disconnect requirements and where the disconnect must be located.

Article 430

NEC 430 — Motor Circuits: The 125% Rule, Locked-Rotor Currents, and the Largest-Motor Adder

NEC 430 governs motor branch circuits. Conductors are sized at 125% of full-load amps (FLA) per the motor nameplate. The largest motor adds 25% to the service load calc. Common in residential for well pumps, pool pumps, and HVAC.

Article 440

NEC 440 — Air-Conditioning Equipment: Disconnects, Conductor Sizing, and the Maximum Overcurrent Rating

NEC 440 governs A/C and heat pump equipment. Branch conductors size to the nameplate Minimum Circuit Ampacity (MCA), breakers to the Maximum Overcurrent Protection (MOP). Disconnect must be in sight of the unit per 440.14.

Article 625

Electric vehicle charging — the 125% continuous-load rule.

NEC 625 — EV Charger Sizing and the 125% Continuous-Load Rule

EV chargers are continuous loads under NEC 625.42. The branch circuit must be sized at 125% of the charger nameplate. What this means for breaker, conductor, and load-calc decisions.

Article 690

Solar PV systems — rapid shutdown, conductor sizing, disconnects.

NEC Article 690 — Solar PV: Rapid Shutdown, Conductor Sizing, and DC Disconnect Requirements

NEC 690 covers solar photovoltaic systems: rapid-shutdown requirements (690.12), DC and AC disconnects (690.13/690.15), conductor sizing for PV output, and grounding.

Article 702

Optional standby systems — whole-house generators and ATS.

NEC Article 702 — Optional Standby Generators: ATS, Wiring, and the 200% Rule

NEC 702 covers optional standby systems — typical residential whole-house generators with automatic transfer switches. ATS rating, generator conductor sizing, and where the ATS goes in the system.

Article 705

Interconnected power production — solar back-feed and supply-side taps.

NEC 705.11(D) — When to Use a Supply-Side Tap on Solar PV Installs

Supply-side connections per NEC 705.11(D) are the cleanest answer when the existing main panel busbar can't accept a back-fed breaker for solar. Required wire sizing, AC disconnect, and AHJ expectations.

Article 706

NEC 706 — Energy Storage Systems: Tesla Powerwall, Enphase IQ Battery, and the New 2023 Rules

NEC 706 covers Energy Storage Systems (ESS) — Tesla Powerwall, Enphase IQ Battery, FranklinWHP, etc. Disconnect requirements, working space, signage, and how ESS interacts with solar PV and the main service.