12-gauge vs 14-gauge extension cords: 12-gauge wins for real work

12-gauge handles 20 amps and is safer for power tools, shop vacs, and space heaters; 14-gauge is fine for lights and phone chargers under 15 amps. Plug a table saw into 14-gauge and you risk tripping a breaker or fire from voltage drop. For cords over 50 feet, bump up to 10-gauge.