Wire gauges, breaker sizes, and safety guidelines for residential electrical work. Helpful for basic repairs and understanding your home's wiring.
Quick answer
| Breaker | Copper wire and typical circuit |
|---|---|
| 15 amp | 14 AWG: lighting and general receptacles |
| 20 amp | 12 AWG: kitchen, bathroom, laundry, outdoor |
| 30 amp | 10 AWG: electric dryer, water heater |
| 40 amp | 8 AWG: electric range, large AC unit |
Copper conductors under the NEC. Check your local code and the appliance nameplate.
Doing this on a real job? Install recessed lights: materials, tools and steps sized to your numbers.
Get the plan| Wire Gauge (AWG) | Max Amperage | Typical Use |
|---|---|---|
| 14 AWG | 15A | Lighting circuits, receptacles |
| 12 AWG | 20A | Kitchen, bathroom, outdoor receptacles |
| 10 AWG | 30A | Electric dryers, water heaters |
| 8 AWG | 40A | Electric ranges, large AC units |
| 6 AWG | 55A | Welders, large appliances |
Understanding Cable Labels
Cable designations like "14-2" or "12-3" indicate the wire gauge and number of conductors. The first number is the AWG gauge, the second is the number of current-carrying conductors (plus a ground wire which isn't counted).
| Cable Type | Contains | Typical Use |
|---|---|---|
| 14-2 | 1 black (hot), 1 white (neutral), 1 bare (ground) | 15A circuits - lights, standard outlets |
| 14-3 | 1 black, 1 red, 1 white, 1 bare | 15A 3-way switches, ceiling fans with separate switch |
| 12-2 | 1 black (hot), 1 white (neutral), 1 bare (ground) | 20A circuits - kitchens, bathrooms, garages |
| 12-3 | 1 black, 1 red, 1 white, 1 bare | 20A 3-way switches, split receptacles, multi-wire branch circuits |
| 10-2 | 1 black (hot), 1 white (neutral), 1 bare (ground) | 30A circuits - electric water heaters, AC units |
| 10-3 | 1 black, 1 red, 1 white, 1 bare | 30A 240V circuits - electric dryers |
| 6-3 | 1 black, 1 red, 1 white, 1 bare | 50A 240V circuits - electric ranges, ovens |
Key Differences:
| Breaker Size | Wire Gauge | Application |
|---|---|---|
| 15A | 14 AWG | Standard lighting and receptacles |
| 20A | 12 AWG | Kitchen, bathrooms, laundry |
| 30A | 10 AWG | Electric dryer, water heater |
| 40A | 8 AWG | Electric range, large AC |
| 50A | 6 AWG | Electric range (common size) |
Single Gang
2" x 3" - One device
Double Gang
2" x 4" - Two devices
Old Work (Retrofit)
For existing walls
New Work
For new construction
| Color | Function | Notes |
|---|---|---|
| Black | Hot | Always assume energized |
| Red | Hot (2nd hot) | Used in 3-way switches, 240V |
| White | Neutral | Returns current to panel |
| Green | Ground | Safety ground |
| Bare Copper | Ground | Safety ground |
Standard Receptacles: 12-16" above floor
Kitchen Counter Receptacles: 4" above countertop
Switches: 48" above floor (center of box)
ADA Compliant Receptacles: 15-48" above floor
ADA Compliant Switches: 48" maximum above floor
This comprehensive electrical work cheat sheet is designed for DIY homeowners and beginner electricians who need quick access to essential wiring information. Whether you're installing a new outlet, replacing a light switch, or planning a more extensive electrical project, this guide provides the critical specifications you need to work safely and meet code requirements.
Understanding wire gauge sizes, circuit breaker ratings, and proper safety protocols is essential for any electrical work. This reference covers the most common residential electrical scenarios, from determining what size wire for a 20 amp circuit to understanding the color coding of electrical wires. While this guide provides valuable reference information, always consult local building codes and consider hiring a licensed electrician for complex projects or if you're uncertain about any aspect of the work.
Electrical work requires precision and attention to safety. Mistakes can result in fire hazards, code violations, or serious injury. Use this guide as a quick reference, but never skip important safety steps like turning off power at the breaker and verifying circuits are de-energized before beginning work.
Having quick access to electrical specifications helps ensure your projects are safe, code-compliant, and professionally executed. This guide saves you time and helps prevent costly mistakes.
Permit check
New circuits and new outlets are permitted electrical work almost everywhere.
Inspections: Rough-in before drywall, then Final
Job checklist
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Code changes
Model codes update every three years, and the parts that move this sheet are GFCI and AFCI requirements, wire sizing and receptacle spacing. Leave an email and we will tell you when we update it for a new code cycle.
Local code notes for your county
Cities and counties amend the NEC, and the amendments are what inspectors fail people on. Tell us where the job is and your project gets the notes that apply there.
Ask about your situation. Posting needs a free account, and your question carries over so you get an answer with your project in view. Questions we hear often get answered on this sheet.
Use this on a project
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