🔐 DIY Faraday Cage for Generators & Power Stations (Bigger, Better, Tested)
JR (DIY Prepper) built a full-size Faraday cage to protect a solar power station / inverter generator (e.g., EcoFlow Delta 3 Ultra, Honda EU2000i) from EMP/E1. He shares what worked, what didn’t, and how to cut costs without losing protection.
Why it matters
E1 (fast, high-freq) can fry small electronics & gensets
E2/E3 mostly threaten long lines & the grid
Cage = extra insurance for backup power + radios
Build snapshot
Frame: 2×2 top/bottom, 2×3 verticals (approx. 32″ × 20″ × 20″)
Skin: Copper mesh + conductive copper tape over all seams
Lid: Cardboard lid wrapped with mesh + conductive gasket (foil-wrapped weatherstrip)
Floor: Particle board + rubber mat
Overlap & continuity are the real keys (not “airtight”)
Testing (quick & practical)
NOAA weather radio → static when lid closed
Phone inside: no ring, no “Find My” (Wi-Fi on/off)
Effective from ~162 MHz up to 2.4 GHz+
Cost & lessons learned
Copper mesh + tape = pricey (>$200 in mesh/tape alone)
Cheaper alt: heavy-duty aluminum foil in multiple crossed layers + foil tape on seams
Add more lid overlap, cover seams, and avoid long ground leads (can act like antennas)
Best practice: nest protection (Faraday bag inside trash-can cage, or foil box over mesh cage)
Materials (budget version)
2×2 & 2×3 lumber, screws/pocket screws
Heavy-duty aluminum foil (3–5 layers, perpendicular), foil tape (conductive adhesive)
Cardboard sheathing (smooth base for foil), weatherstrip + foil for a conductive gasket
Optional: Faraday bags for radios, flashlights, charge controllers
Tips
Smooth sharp edges; avoid tears in mesh/foil
Prioritize continuous conductive path with generous overlap at every seam
Test before you trust (radio + phone checks)
What are you protecting first—generator, solar power station, or comms gear—and what build materials worked best for you?