What size extension cord do you need for a generator?
The wrong extension cord can be a weak link in your generator setup, causing voltage drop or overheating.
This guide explains basic cord sizing ideas so you can choose something safer for your loads and distances.
Why cord size matters
Extension cords that are too light for the load can overheat, drop voltage, and damage equipment. Generator cords should be heavy-duty, outdoor-rated, and properly sized for both amperage and length.
Basic cord sizing guidelines
- For smaller loads up to 15 amps and shorter runs, a 12-gauge cord is a solid choice.
- For 20-amp circuits or longer distances, many people step up to 10-gauge cords.
- Look for cords labeled for outdoor use with appropriate plug types for your generator.
Using dedicated generator cords
Many setups use generator-specific cords and inlet boxes that simplify connections and keep wiring sized correctly. An electrician can help design a setup that matches your generator and panel.
Tip: you can always use the calculators on the GeneratorCalc home page to turn these ideas into rough numbers for your specific generator and situation.