{
  "id": "protocols:body-voltage-survey",
  "collection": "protocols",
  "slug": "body-voltage-survey",
  "name": "Body-voltage measurement",
  "summary": "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.",
  "status": "verified",
  "lastVerified": "2026-08-12",
  "data": {
    "aliases": [
      "how to measure body voltage"
    ],
    "goal": "Quantify capacitive coupling from building wiring to a person at the sleeping position, and identify which circuits and devices contribute.",
    "quantity": "body-voltage",
    "equipment": [
      "body-voltage-kit",
      "ac-electric-field-meter"
    ],
    "steps": [
      "Establish and document the ground reference: protective earth at a socket, or a dedicated ground rod. Readings are not comparable across different references.",
      "Lie or sit in the normal sleeping position, holding the hand electrode, with the meter on AC millivolts.",
      "Record the baseline with the room in its normal night-time state.",
      "Unplug items one at a time — bedside lamp, charger, extension lead — recording the reading after each.",
      "Switch off individual circuits at the consumer unit, recording after each, to attribute the remainder to specific circuits.",
      "Repeat after any mitigation (demand switch, shielded cable, shielding paint) using the identical reference and posture.",
      "Report the ground reference, posture and circuit states alongside every number."
    ],
    "pitfalls": [
      "Comparing a reading against someone else's number when the ground reference differs",
      "Assuming a low body voltage means low magnetic field exposure — the two are independent",
      "Grounding a shielding surface incorrectly and creating a larger field than before",
      "Working inside a consumer unit without a qualified electrician"
    ],
    "interpretAgainst": [
      "limits:sbm-2024-electric-bands"
    ],
    "related": [
      "emitters:bedroom-wiring-electric-field",
      "shielding:demand-switch"
    ]
  },
  "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/protocols/body-voltage-survey",
    "html": "https://emfbase.com/protocols/body-voltage-survey",
    "markdown": "https://emfbase.com/protocols/body-voltage-survey.md",
    "collection": "https://emfbase.com/api/protocols"
  }
}