A corded line trimmer is an electric weed cutter that runs on household AC power through an extension cord and spins a nylon line to slice grass.
The spinning line — not a metal blade — does the cutting. Centrifugal force stiffens the nylon as the head whips around, and only the tip touches the grass. The cord is the trimmer’s defining advantage and main annoyance: unlimited runtime, no battery, no gas, but you stay tethered to an outlet.
How a Corded Trimmer Cuts Grass
The motor spins a spool at the cutting head, and the line’s spinning tip is the only part that touches vegetation. On a typical corded model, the head turns fast. The PS8213 13-inch corded trimmer manual lists a no-load speed of 9000 RPM, and Greenworks rates its 4 Amp 13-inch model at up to 9000 RPM as well. At that speed the line straightens and stiffens, turning limp nylon into a cutting tool.
Corded models run on standard household power. The PS8213 manual specifies AC 120 V, 60 Hz, drawing 4 amps. Amperage varies by model: CRAFTSMAN sells 3.5 Amp corded string trimmer/edgers with a 12-inch cutting swath, and the Greenworks unit steps up to 4 Amps. More amps mean more cutting muscle, most noticeable in thick weeds.
How the Line Advances as You Trim
The line extends about 1/4 inch per stop-start cycle on many models and keeps feeding until it reaches the blade on the grass deflector, which trims it to the right length. Greenworks calls this auto-feed, and on its trimmers the line also advances when you bump the head against the ground.
Auto-feed models do the work for you: release the trigger, the motor stops, and the spool lets out line; press the trigger again and the line snaps to full extension. Bump-feed and trigger-cycling versions work the same way in practice — they just respond to a different action. Either way, you never stop to hand-pull line.
Line diameter matters more than most owners realize. The PS8213 manual calls for 0.065-inch monofilament line specifically. Thicker than the manual allows and the head can bog down or overheat; thinner and the line snaps constantly. Match the size printed in your manual, every time.
| Trimmer Spec | Typical Corded Value | Why It Matters |
|---|---|---|
| Power source | 120 V AC household outlet | No battery, no fuel, unlimited runtime |
| Motor amperage | 3.5 to 5.5 Amps | Higher amps cut thicker weeds |
| No-load speed | Up to 9000 RPM | Faster spin stiffens the line for cleaner cuts |
| Cutting swath | 12 to 15 inches | Wider swath covers more ground per pass |
| Line diameter | 0.065 in. monofilament | Wrong size causes feed jams or breakage |
| Feed type | Auto-feed or bump-feed | Both extend line without stopping work |
| Cord requirement | Approved outdoor extension cord | Indoor cords are not rated for yard use |
Safety Rules You Cannot Skip
Use only an approved outdoor extension cord, keep it routed through the tool’s cord retainer, and keep the cable clear of the cutting head. The line will cut a cord as easily as grass — the most common corded-trimmer accident.
Never trim in wet conditions. A University of Hawaii string trimmer safety manual states the tool should not be used in wet weather and the extension cord must be in good condition before you start. If the cord gets nicked, disconnect immediately.
Wear eye and face protection, gloves, long pants, and boots, and add hearing protection for longer sessions. Toro’s safety documentation and the University of Hawaii program both recommend that kit.
Mind your footing. Keep the head below waist level, cut with the tip of the line rather than the hub, and move slowly. Burying the head in grass or dragging it along the ground only burns through line.
Where a Corded Trimmer Fits Best
Corded trimmers shine on small to mid-size yards where an outlet is within cord reach. They cost less than comparable battery or gas models and never run out of power mid-job. The trade-off: gas and battery trimmers go anywhere the yard goes, while a corded model stops where your extension cord stops. For most suburban front yards, driveways, and fence lines, that is a non-issue.
If you are weighing specific models, our breakdown of the best corded line trimmers we tested covers swath width, amp ratings, and feed systems side by side.
FAQs
Can a corded trimmer cut thick weeds?
Yes, within limits. A 4 Amp or higher corded model handles tall grass and light weeds, especially in auto-feed mode. Dense, woody brush will stall a corded motor; for that, a gas trimmer or brush cutter is the right tool.
Do corded trimmers need any maintenance?
Very little. No fuel to mix, no battery to store, so upkeep is keeping the cutting head clean, replacing line with the diameter your manual specifies, and inspecting the extension cord before each use. If the cord shows nicks or worn insulation, replace it rather than tape it.
How long can an extension cord be?
That depends on the cord’s wire gauge, not a universal number. Heavier-gauge outdoor cords carry power farther without voltage drop. A shorter, thicker cord gives the motor cleaner power; an overly long, thin cord can make the trimmer feel weak. Check the cord’s rating against the trimmer’s amp draw.
References & Sources
- University of Hawaii Office of Procurement and Facilities. “Use of String Trimmers.” Safety program manual covering wet-condition restrictions, cord condition, and protective gear.
- Toro. “String Trimmer Safety.” Manufacturer safety documentation on trimmer handling and protective equipment.
- Queensland Department of Education. “Safe Operating Procedure: Line Trimmer.” Standard operating procedure on line trimmer use and hazards.