Ampacity

Definition

Ampacity is how much current a cable can carry without overheating the insulation. It depends on conductor size, insulation temperature rating, bundling and ambient heat. Voltage-drop percent is a separate performance budget. Size copper for both: the drop formula for volts lost, and a conservative ampacity table so the insulation is not the fuse. Then protect the cable with a fuse or breaker at 125% of continuous current, not above that ampacity.

Calculators that use this

• wiring

  12V/24V/48V DC Wire Gauge (AWG) Calculator

  Pick a copper AWG size for 12V, 24V or 48V DC runs from current, one-way length and a 3% voltage-drop budget.

• wiring

  DC Inline Fuse & Circuit Breaker Sizer

  Size a DC fuse or breaker at 125% of continuous current, then check it against copper cable ampacity.

• wiring

  Grounding Rod & Wire Sizer

  Estimate copper GEC size for a ground rod or other electrode and EGC size from the DC overcurrent device.