/**
 * Simplified electrical clearance guidance.
 *
 * IPC-2221's actual clearance tables (Table 6-1 through 6-4) have many bands split
 * by altitude, coating, and external/internal placement, with fine voltage
 * breakpoints. Reproducing that table precisely risks getting a breakpoint subtly
 * wrong — and a wrong *clearance* value is a safety-relevant mistake in a way a wrong
 * *trace-width* estimate on the conservative side is not. Rather than approximate the
 * fine breakpoints, this module offers a small number of deliberately coarse,
 * rounded-up bands that follow IPC-2221's general "clearance grows with voltage"
 * shape, clearly labeled as a starting estimate.
 *
 * **Always consult the current IPC-2221 revision's actual tables (or your
 * fabricator's certified minimums) before finalizing a safety-critical or
 * regulatory (e.g. mains-adjacent) clearance.**
 *
 * @module
 */
export type ConductorLocation = 'external' | 'internal';
export interface ClearanceInput {
    /** Voltage difference between the two conductors (peak, if AC), in volts. */
    voltageV: number;
    location: ConductorLocation;
}
export interface ClearanceResult {
    minClearanceMm: number;
    minClearanceMils: number;
    bandMaxVoltageV: number;
    source: string;
    caveat: string;
    outOfRange?: boolean;
}
export declare function lookupClearance(input: ClearanceInput): ClearanceResult;