Your extension cord must be as thick as the wall wire feeding the outlet. If your tool draws 15 amps, you need a 14 AWG cord (or thicker). How to Calculate the Right Size If you’re installing a new circuit, use the 80% rule (Continuous Load Rule). If a device runs for more than 3 hours (lights, EV charger, heaters), you can only load the breaker to 80% of its rating.
Disclaimer: This guide is for informational purposes. Electrical work can be lethal. Always consult a licensed electrician and check your local building codes before beginning any electrical project. cable size
When you flip a light switch or plug in a space heater, you expect the electricity to just work . But behind your drywall, a silent battle is taking place. The copper (or aluminum) inside your cables is resisting the flow of current, and that resistance creates heat . Your extension cord must be as thick as
| Gauge (AWG) | Max Amps (Breaker) | Typical Use | | :--- | :--- | :--- | | | 15 Amps | Lighting circuits, general outlets (bedrooms) | | 12 | 20 Amps | Kitchen small appliances, bathroom outlets, garages | | 10 | 30 Amps | Water heaters, window AC units, RV hookups | | 8 | 40 Amps | Small sub-panels, oven ranges | | 6 | 55 Amps | Large sub-panels, EV chargers, central AC | If a device runs for more than 3