Start by matching the cord to your generator’s outlet and amperage. Most portable units use:

• 30A 120/240V (4-prong): NEMA L14-30 locking cord, typically 10 AWG.
• 30A 120V (3-prong): NEMA L5-30 locking cord, typically 10 AWG.
• 50A 120/240V (4-prong): NEMA 14-50 or SS2-50 locking cord, often 6/3 + 8/1 AWG.

For plugging in individual appliances, use heavy-duty outdoor-rated extension cords (SJTW/STW) with grounded plugs and the right gauge for the load. Keep runs as short as practical to limit voltage drop. If powering home circuits, a transfer switch or inlet box installed by a licensed electrician is advisable. Choosing a cord that’s ETL/UL listed and weather resistant can help with safe, reliable use.

The “80% rule” is a practical guideline many users follow to keep the total load around 80% of a generator’s rated output. Operating with a buffer can help reduce heat, manage voltage drop, and provide headroom for startup surges.

• Why it matters for cords: A lighter load reduces stress on cables and connectors.
• Sizing: Choose cords with amp ratings equal to or higher than the circuit (e.g., 30A circuits use 10 AWG generator cords; 50A circuits use 6/3 + 8/1 AWG).
• Length: Shorter, heavier-gauge cords can help limit voltage drop.

This guideline isn’t a substitute for the generator’s manual or local codes, but it can help you plan loads and cord choices more conservatively.

For small appliances plugged into a generator’s household outlets, 12 AWG outdoor cords usually handle higher current with less voltage drop than 14 AWG, which can be helpful over longer runs. 14 AWG may be suitable for lighter loads over shorter distances on 15A circuits.

• Important: These sizes are for standard 5-15/5-20 style cords. They’re not appropriate for 30A or 50A generator receptacles.
• For 30A: Use 10 AWG cords with the correct NEMA plug (e.g., L5-30 or L14-30).
• For 50A: Use cords built with 6/3 + 8/1 conductors and the proper NEMA (e.g., 14-50 or SS2-50).

Always choose outdoor-rated (SJTW/STW) cords and keep lengths reasonable to help reduce voltage drop.

Generator extension cords are typically heavy-duty, outdoor-rated cables with copper conductors and durable jackets:

• Jacket types: STW or SJTW for weather resistance and flexibility.
• Connectors: Locking NEMA L14-30 (30A 120/240V) or L5-30 (30A 120V); straight-blade TT-30 for RVs (30A 120V); and 14-50/SS2-50 for 50A 120/240V setups.
• Conductors: 10 AWG is common for 30A cords; 6/3 + 8/1 for 50A cords.

Many cords include features like twist-lock ends for a secure connection, LED power indicators, and organizers for storage. Look for UL/ETL listings and match voltage, amperage, and plug type to your generator and equipment for a compatible setup.

There isn’t one “right” length, but shorter and heavier-gauge is generally better to help limit voltage drop and heat. Practical generator cords often range from 10–50 ft (some longer options exist), but needs vary by setup.

• 30A circuits: 10 AWG cords; shorter lengths (e.g., 25–50 ft) can help reduce voltage drop.
• 50A circuits: 6/3 + 8/1 cords; keep runs as short as practical.
• Avoid daisy-chaining: Linking multiple cords can increase resistance and trip hazards.
• Use outdoor-rated cords: SJTW/STW, fully uncoiled, with connections kept dry and off the ground.

If you’re powering home circuits, a properly installed inlet box/transfer switch by a licensed electrician is advisable.