Extension Cords

Power your boat, shop, or backyard projects with confidence using Sierra 15 Amp and 13 Amp outdoor extension cords, engineered with durable 12/3, 14/3, and 16/3 SJTOW cable to deliver reliable performance in the harshest marine environments while remaining versatile for everyday outdoor use. Built with marine-grade toughness, these heavy-duty extension cords are designed to withstand moisture, UV exposure, abrasion, and temperature extremes without cracking or failing, making them ideal for dockside power, marine maintenance, lawn equipment, power tools, and general outdoor applications. The high-visibility jacket—available in bright, easy-to-spot colors—helps reduce tripping hazards and improves safety in busy work areas, while the grounded 3-prong design ensures consistent, safe power delivery for outdoor tools, lighting, and equipment. Flexible yet rugged, Sierra extension cords combine corrosion-resistant durability with dependable conductivity, making them the smart choice when you need to buy outdoor extension cords that are heavy duty, marine grade, and built to perform in demanding conditions.