Demand switch (Netzfreischalter)
A relay in the consumer unit that de-energises a circuit when no load is drawing current and re-energises it when a switch is thrown, eliminating the bedroom AC electric field overnight.
filterelf electric
Last verified 12 August 2026.
Also searched as: Netzfreischalter, automatic circuit cutoff, demand shutoff
- Form
- filter
- Targets
- elf electric
- Grounding required
- No
Failure modes
- Does nothing for magnetic fields, RF, or circuits other than the one it controls
- Standby loads on the protected circuit keep it energised, defeating the purpose
- Requires a qualified electrician and must not be fitted to circuits serving safety devices such as alarms or medical equipment
Related records
- Bedroom wiring AC electric field
Live conductors in walls and in lamp flex create a power-frequency electric field that couples to the body whether or not any current flows; building biology grades below 1 V/m with ground reference as 'no anomaly'.
Sources & emitters
- Building Biology SBM-2024 AC electric field 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'.
Exposure limits
Sources
- sbm-2024 Building Biology Evaluation Guidelines for Sleeping Areas (SBM-2024) — Institut für Baubiologie + Nachhaltigkeit (IBN), 2024. ngo, link checked 2026-08-12.
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