Calculators are a Pro feature

The NEC 2026 Box Fill and Conduit Fill calculators with live compliance gauges are available to Electrical Safety Compass Pro subscribers. Subscribe to unlock instant, code-accurate fill calculations.

Box Fill (NEC 314.16)

Live conductor & device fill compliance gauge.

Conduit Fill (Ch. 9)

Trade-size & conductor area capacity checks.

Reference data per NFPA 70 National Electrical Code 2026. Always verify against the published code and local AHJ requirements.

Electrical Safety Compass is a supplemental study aid and field reference tool only. It is designed to help prepare apprentices for their licensing exams and to assist working electricians in the field. It does not replace any required classroom instruction, formal apprenticeship coursework, or supervised on-the-job training mandated by your state, licensing board, or apprenticeship program. Always complete all legally required education and supervised hours before performing electrical work.