{
  "id": "shielding:shielding-demand-switch",
  "collection": "shielding",
  "slug": "demand-switch",
  "name": "Demand switch (Netzfreischalter)",
  "summary": "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.",
  "status": "verified",
  "lastVerified": "2026-08-12",
  "data": {
    "aliases": [
      "Netzfreischalter",
      "automatic circuit cutoff",
      "demand shutoff"
    ],
    "form": "filter",
    "targets": [
      "elf-electric"
    ],
    "requiresGrounding": false,
    "failureModes": [
      "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": [
      "emitters:bedroom-wiring-electric-field",
      "limits:sbm-2024-electric-bands"
    ]
  },
  "sources": [
    {
      "id": "sbm-2024",
      "title": "Building Biology Evaluation Guidelines for Sleeping Areas (SBM-2024)",
      "publisher": "Institut für Baubiologie + Nachhaltigkeit (IBN)",
      "url": "https://buildingbiology.com/site/downloads/SBM-2024_EVALUATION_GUIDELINES_EN.pdf",
      "year": 2024,
      "kind": "ngo",
      "retrieved": "2026-08-12"
    }
  ],
  "links": {
    "self": "https://emfbase.com/api/shielding/demand-switch",
    "html": "https://emfbase.com/shielding/demand-switch",
    "markdown": "https://emfbase.com/shielding/demand-switch.md",
    "collection": "https://emfbase.com/api/shielding"
  }
}