Residential Electrical Code Requirements
Every residential electrical requirement under the National Electrical Code (NEC). GFCI, AFCI, panel sizing, grounding, EV chargers, load calcs, and the violations that fail inspections most often.
Which NEC edition applies to you?
Most US states are on the 2020 or 2023 NEC. The 2026 NEC published in fall 2025 and is rolling out across states between 2026 and 2028. States also adopt local amendments, so a 2023 NEC state may modify GFCI or AFCI rules. Verify your current edition with your local building department before wiring.
GFCI Protection
NEC 210.8| Bathrooms | All 125V and 250V receptacles, required since the 1970s |
| Kitchens | All countertop receptacles, dishwasher branch circuit (since 2014), and within 6 ft of a sink |
| Outdoors and garages | All 125V receptacles, including EV outlets serving cord-and-plug EVSE |
| Laundry areas | Within 6 ft of laundry sink, plus washing-machine receptacle |
| Basements and crawlspaces | All 125V and 250V receptacles, unfinished and finished, per 2020 NEC |
AFCI Protection
NEC 210.12| Required locations | Bedrooms, living rooms, family rooms, dining rooms, hallways, closets, and laundry areas |
| Branch circuits covered | All 120V, 15A and 20A circuits feeding the above rooms |
| Acceptable devices | Combination-type AFCI breaker, outlet-branch-circuit AFCI, or dual-function AFCI/GFCI device |
| Exclusions | Bathrooms, kitchens, garages, and outdoor circuits are GFCI-only (not AFCI) |
| Replacement rule | Replacing a receptacle in an AFCI-required room triggers the AFCI requirement on that circuit |
Receptacle Placement
NEC 210.52| General rule | No point along a wall can be more than 6 ft from a receptacle (12-ft spacing rule) |
| Wall segments | Any wall segment 2 ft or wider needs a receptacle |
| Kitchen countertops | Receptacles within 20 inches of every countertop point, 4-ft max spacing, 12-inch min island rules |
| Bathrooms | At least one GFCI receptacle within 3 ft of the outside edge of each basin |
| Outdoor | One GFCI receptacle at front and one at back of dwelling, accessible from grade level |
Load Calculations
NEC 220| General lighting load | 3 VA per square foot of habitable area for dwellings |
| Small appliance branch circuits | Two required at 1,500 VA each (kitchen and dining) |
| Laundry circuit | 1,500 VA minimum for dedicated laundry branch circuit |
| Optional method | NEC 220.82 allows first 10 kVA at 100%, remainder at 40% for single-family dwellings |
| Continuous loads | Sized at 125% of the continuous load per NEC 210.19 and 215.2 |
Service Equipment
NEC 230| Minimum service size | 100A for modern dwellings per NEC 230.79(C) |
| Service conductor sizing | Table 310.12 for dwelling services (83% rule for SE cable) |
| Service disconnect | Maximum of 6 switches or breakers, grouped in one location per 230.71 |
| Working clearance | 30 inches wide, 36 inches deep, 6 ft 6 inches tall per NEC 110.26 |
| Outdoor emergency disconnect | Required since 2020 NEC for one- and two-family dwellings per 230.85 |
Overcurrent Protection
NEC 240| Breaker-to-wire match | 14 AWG copper = 15A, 12 AWG copper = 20A, 10 AWG copper = 30A (60C column) |
| Tap rules | 10-ft, 25-ft, and outside feeder tap rules per 240.21 |
| Location | Readily accessible, not in bathrooms or clothes closets per 240.24 |
| Handle ties | Required for multi-wire branch circuits (MWBC) per 210.4(B) |
| Series rating | Manufacturer-listed only, marked on the panel directory per 240.86 |
Grounding and Bonding
NEC 250| Grounding electrode system | Ufer, ground rod, ground plate, metal water pipe, building steel per 250.52 |
| Ground rod | Minimum 8 ft in earth; second rod required if single rod exceeds 25 ohms |
| Grounding electrode conductor | Sized per Table 250.66 based on service conductor size |
| Main bonding jumper | Connects neutral to ground at service disconnect, per 250.28 |
| Equipment grounding conductor | Sized per Table 250.122 based on overcurrent device |
Wiring Methods
NEC 300| Support intervals | NM cable: within 12 inches of a box, then every 4.5 ft per 334.30 |
| Protection from physical damage | NM through studs within 1.25 inches of the face requires nail plates per 300.4 |
| Bend radius | 5 times the diameter for conduit, no more than 360 degrees total between pull points |
| Box fill | Calculated per NEC 314.16, counting conductors, devices, clamps, and grounds |
| Cable in attics | Running boards or guard strips where subject to damage per 334.23 |
Conductor Ampacity
NEC 310| 14 AWG copper | 15A at 60C column (Table 310.16) |
| 12 AWG copper | 20A at 60C column |
| 10 AWG copper | 30A at 60C column |
| 8 AWG copper | 40A at 60C, 50A at 75C (stranded in conduit) |
| Dwelling service ampacity | Table 310.12 allows reduced sizes for main service conductors |
Box Fill
NEC 314.16| Conductor volume | 14 AWG = 2.0 cu in, 12 AWG = 2.25 cu in, 10 AWG = 2.5 cu in |
| Device count | Each yoke (switch or receptacle) counts as 2 conductors of the largest wire attached |
| Grounds | All grounding conductors together count as 1 conductor of the largest size |
| Clamps | All internal cable clamps together count as 1 conductor of the largest size |
| Common box sizes | Single-gang plastic old-work: 14-18 cu in; metal 4 inch square: 21 cu in deep |
Panelboards
NEC 408| Overcurrent protection | Panelboard rated for the available fault current per 408.36 |
| Circuit directory | Legible and specific, not marked "spare" when in use, per 408.4 |
| Working clearance | 30 inches wide, 36 inches deep, 6 ft 6 inches tall (same as service) per 110.26 |
| Location restrictions | Not in bathrooms, not in clothes closets per 240.24(D) and (E) |
| Max circuits | Limited to the panel rating; no double-tapping breakers unless listed |
EV Chargers (EVSE)
NEC 625| Continuous load derate | 125% per 625.41; a 48A charger needs a 60A breaker |
| Disconnecting means | Required per 625.43 for EVSE rated over 60A or over 150V to ground |
| GFCI requirement | Cord-and-plug EVSE on NEMA 14-50 requires GFCI per 625.54 (2020 NEC) |
| Load management | NEC 625.42 permits automatic load management to avoid panel upgrades |
| Working clearance | Standard 110.26 clearance rules apply to the EVSE disconnect |
Pools, Spas, and Hot Tubs
NEC 680| Equipotential bonding | 8 AWG solid copper bonding grid around pool shell per 680.26 |
| GFCI protection | All pool receptacles within 20 ft of the pool per 680.22 |
| Receptacle distance | No receptacle closer than 6 ft to inside walls of pool (with exceptions) |
| Overhead clearance | Service drop 22.5 ft above pool water surface per 680.8 |
| Hot tub disconnect | Readily accessible, in sight, not less than 5 ft from tub edge per 680.41 |
Most Common Electrical Code Violations
These are the issues inspectors fail residential electrical work on most often. Fixing these before the rough-in inspection saves re-inspection fees and project delays.
Wrong breaker size for the wire gauge
A 20A breaker on 14 AWG wire, or a 30A breaker on 12 AWG wire. Oversized breakers are the #1 fire hazard NEC 240.4 is designed to prevent.
Missing AFCI protection
Bedroom, living-room, and family-room circuits installed on standard breakers. NEC 210.12 has required AFCI in dwelling living spaces since 2008; inspectors check every one.
Incomplete or inaccurate panel labeling
Blank directory, "spare" on a live circuit, or circuits labeled by room without specific location. NEC 408.4 requires legible, specific labels.
Insufficient working clearance at the panel
Boxes, shelving, water heaters, or washing machines within the 30-inch wide by 36-inch deep clearance zone. NEC 110.26 violation every time.
Grounding electrode or bonding errors
Single ground rod without the second rod when resistance exceeds 25 ohms, missing main bonding jumper, or no bonding at the metallic water pipe.
Overloaded neutral or shared circuits
Two circuits sharing a neutral without a handle-tied breaker (multi-wire branch circuit violation per 210.4), or a kitchen running on a single small-appliance branch circuit.
Deep Dives by Code Topic
The detailed guide for each major electrical code topic, with state variations, common failures, and the measurements inspectors actually check.
Panel Upgrade Code
100A vs 200A vs 400A, NEC 408 and 230, working clearance, and when a swap is required.
EV Charger Install Code
NEC 625, hardwired vs NEMA 14-50, 125% derate, and the 30C tax credit.
Grounding and Bonding
NEC 250, Ufer vs rod, GEC sizing, and the bonding points inspectors check.
Residential Load Calculation
NEC 220 optional vs standard method, demand factors, and a worked example.
Electrical Permit Guide
Do you need a permit? Costs, scope, and how to apply.
Find a Licensed Electrician
Vetted electricians by state and city, with phone numbers and license data.
Electrical Calculators
Panel upgrade cost, EV charger install, load calc, and more.
Code requirements are based on the 2020 and 2023 editions of the National Electrical Code (NEC / NFPA 70). Your state or local jurisdiction may have adopted a different edition or local amendments. Electrical work on a dwelling unit requires a permit in most jurisdictions and, in most states, a licensed electrician. Always verify requirements with your local building department before starting work. This is not engineering or legal advice.