# Faraday cage

> A continuous grounded conductive enclosure. Effective in principle, and in practice limited entirely by its apertures.

- Canonical URL: https://emfbase.com/glossary/faraday-cage
- Collection: Glossary
- Record id: `glossary:faraday-cage`
- Status: verified
- Last verified: 2026-08-12
- JSON: https://emfbase.com/api/glossary/faraday-cage

## Key values

- **Category:** physics

## Definition

A Faraday cage excludes external electric fields and, if the conductor is continuous relative to the wavelength, radiofrequency fields. It does not exclude low-frequency magnetic fields, which pass through ordinary conductors essentially unattenuated. Any aperture larger than a small fraction of the wavelength behaves as a slot antenna, so seams and openings determine real performance — and a transmitter left inside a partial enclosure raises levels within it by reflection.

## Sources

- `sbm-2024` Institut für Baubiologie + Nachhaltigkeit (IBN) (2024). *Building Biology Evaluation Guidelines for Sleeping Areas (SBM-2024)*. https://buildingbiology.com/site/downloads/SBM-2024_EVALUATION_GUIDELINES_EN.pdf — ngo, link checked 2026-08-12

Data licence: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Dataset version 2026.08.1. Retrieved from EMFBase, https://emfbase.com.

This record is reference data, not medical or legal advice. Regulatory limits, scientific guidelines and precautionary values are labelled separately and answer different questions.