Precise Measurement + Safety Margin
This is the fundamental prerequisite for selecting the correct length:
Trace the path: Use a flexible tape measure to trace the route along the wall or desk surface from the socket to the device's power port; do not simply measure the straight-line distance between the two points.
Add a buffer: Allow for an extra 0.3–0.5 meters beyond the measured length to prevent the cable from remaining under constant tension, which could damage the plug terminals or internal copper wiring.
Special scenarios: For setups requiring frequent device movement, increase the buffer to 1 meter to prevent the plug from accidentally disconnecting when the device is dragged.
Recommended "Golden Lengths" for Various Scenarios
Desktop/Bedside (Close-range): Choose 1.2–1.8 meters. Suitable for computers, desk lamps, and bedside chargers; this length avoids cable clutter on the desk while perfectly bridging the gap between standard wall outlets and the device.
Living Room/Cross-room: Choose 3 meters. Suitable for TVs, floor fans, and living room heaters; this allows for flexible reach to distant locations, such as areas around the sofa or outlets in room corners.
ITX PC Builds: Standard lengths do not apply; measure the specific routing distance from the power supply port to the motherboard socket. Add a 2–3 cm margin to the measured value to avoid excess cable tangling behind the back panel or a cable that is too short and pulls the connector loose.
Standard Mid-Tower Cases (Cable Management): For the 24-pin motherboard power cable, a length of ≥55 cm is recommended; for the CPU 4+4 pin cable, ≥60 cm is recommended to ensure smooth routing behind the motherboard tray without tension.
EV Charging:5 meters is the standard choice, covering the distance from most parking spots to the charging station. For special cases where the parking spot is further away, upgrade to an extended 7–8 metercable.
Outdoor/Temporary Construction: Select a 5–10 meter industrial-grade cable with a waterproof sheath based on requirements; this prevents connection looseness caused by frequent dragging or pulling.
