# AC electric field meter

> Reads power-frequency electric field strength in V/m, the quantity that reveals energised wiring behind a bed head even when no current is flowing.

- Canonical URL: https://emfbase.com/meters/ac-electric-field-meter
- Collection: Instruments
- Record id: `meters:ac-electric-field-meter`
- Status: verified
- Last verified: 2026-08-12
- JSON: https://emfbase.com/api/meters/ac-electric-field-meter
- Also known as: E-field meter, electric field meter

## Key values

- **Band covered:** power frequency plus harmonics
- **Quantities measured:** electric field strength
- **Axes:** single
- **Typical price:** $60–$500

## Detects

- Live conductors in walls, floors and ceilings
- Unshielded lamp flex and extension leads near sleeping positions
- Ungrounded metal surfaces acting as re-radiators

## Cannot detect

- Magnetic fields — an unshielded conductor can show a high E field and negligible B field, and vice versa
- Radiofrequency fields

## What to insist on

- A defined measurement mode: potential-free or with ground reference, since the two disagree by a large factor
- A supplied grounding lead if ground-referenced readings are wanted
- Resolution to 1 V/m or better, since precautionary bands start at 1 V/m

## Example models in this class

- TriField TF2
- Gigahertz Solutions ME3830B

## About the model list

Named models illustrate the class and are not endorsements or verified specifications. Confirm the current frequency range and calibration statement with the manufacturer before purchase.

## Related records

- [Body-voltage measurement](https://emfbase.com/protocols/body-voltage-survey): The building-biology method for grading a sleeping area's AC electric field: a high-impedance millivoltmeter, a hand electrode, and a documented ground reference.
- [Building Biology SBM-2024 AC electric field bands](https://emfbase.com/limits/building-biology-ac-electric-bands): Sleeping-area grades with ground reference: below 1 V/m no anomaly, 1–5 weak, 5–50 strong, above 50 V/m extreme; body voltage below 10 mV is 'no anomaly'.

## 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.