Guideline: for a continuously-run load, size the fuse at ≥125% of the steady-state current — a common conservative engineering practice that avoids nuisance blowing from normal tolerance and thermal drift while still protecting the wiring. If there's a brief inrush current (motor start, incandescent lamp, capacitor charging), a slow-blow (time-delay) fuse rated for the continuous current will usually ride through it; a fast-blow fuse sized only for steady-state current will likely trip on that inrush. This is general guidance, not an electrical-code citation — for code-mandated circuits, follow your local wiring regulations.