# ELF (extremely low frequency)

> Fields below about 300 Hz, dominated by the 50 or 60 Hz power supply and its harmonics.

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

## Key values

- **Category:** physics

## Definition

Extremely low frequency covers roughly 3–300 Hz and in practice means power-frequency fields from wiring, appliances, transformers and transmission lines. ELF electric and magnetic fields are treated as separate quantities because they are not coupled at these frequencies, and the biological concern addressed by exposure limits is induced current in tissue, not heating.

## Sources

- `icnirp-2010` International Commission on Non-Ionizing Radiation Protection (2010). *Guidelines for Limiting Exposure to Time-Varying Electric and Magnetic Fields (1 Hz to 100 kHz)*. https://www.icnirp.org/en/publications/article/lf-guidelines-2010.html — guideline, link checked 2026-08-12
- `who-elf` World Health Organization (2007). *Electromagnetic fields and public health: exposure to extremely low frequency fields*. https://www.who.int/teams/environment-climate-change-and-health/radiation-and-health/non-ionizing/exposure — government, 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.