{
  "id": "questions:can-you-shield-magnetic-fields",
  "collection": "questions",
  "slug": "can-you-shield-magnetic-fields",
  "name": "Can you shield a magnetic field?",
  "summary": "Almost no common material blocks ELF magnetic fields; mu-metal gives a factor of 2–5 at high cost. Distance and source correction are the real options.",
  "status": "verified",
  "lastVerified": "2026-08-12",
  "data": {
    "question": "Can I shield magnetic fields from power lines or wiring?",
    "answer": "Barely, and rarely economically. Power-frequency magnetic fields pass through nearly all common building materials, including aluminium foil, conductive paint and shielding fabric, so the only materials that help are high-permeability alloys such as mu-metal, which typically deliver a factor of two to five in a real retrofit and lose their properties if bent or drilled. The effective interventions are distance and fixing the source — correcting a net-current wiring fault, relocating a bed away from the service panel, or reducing the current causing the field.",
    "cluster": "shielding",
    "aliases": [
      "block magnetic field",
      "mu metal shielding",
      "shield power line EMF"
    ],
    "related": [
      "shielding:high-permeability-alloy",
      "emitters:transmission-line",
      "glossary:net-current"
    ]
  },
  "sources": [
    {
      "id": "niehs-emf",
      "title": "Electric and Magnetic Fields",
      "publisher": "National Institute of Environmental Health Sciences",
      "url": "https://www.niehs.nih.gov/health/topics/agents/emf",
      "kind": "government",
      "retrieved": "2026-08-12"
    },
    {
      "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/questions/can-you-shield-magnetic-fields",
    "html": "https://emfbase.com/questions/can-you-shield-magnetic-fields",
    "markdown": "https://emfbase.com/questions/can-you-shield-magnetic-fields.md",
    "collection": "https://emfbase.com/api/questions"
  }
}