Definition

Clearance is the minimum allowed spacing between conductive elements (traces, pads, vias, planes). Clearance rules derive from two considerations: electrical (voltage withstand, creepage distance) and manufacturing (etch capability, yield). High-voltage designs require larger clearances per IPC-2221 tables based on voltage and coating. Standard PCB fabrication maintains 100 µm (4 mil) minimum spacing for 1 oz copper; finer spacing requires advanced processes. Clearance also affects crosstalk between adjacent traces.