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A DIY project I'm working on uses electronics embedded in concrete, including 110V AC heating elements. As I was verifying my wiring before testing the device I was surprised to discover conductivity on the order of ~1MΩ+ between my hot and ground (and also neutral and ground).

Concrete conducts electricity! TIL.

From a standards and safety perspective, what's an acceptable amount of resistance/current to allow between hot and ground?

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  • \$\begingroup\$ I guess the way I worded it is technically wrong. Resistance of about 1MΩ, conductivity of about 1μS. \$\endgroup\$
    – sirbrialliance
    Commented Jul 12 at 20:32
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    \$\begingroup\$ you can edit the question \$\endgroup\$
    – jsotola
    Commented Jul 12 at 20:33
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    \$\begingroup\$ "Concrete conducts electricity!" - yes - google "Ufer ground". \$\endgroup\$
    – brhans
    Commented Jul 12 at 20:59
  • \$\begingroup\$ Concrete is a sponge. It will absorb moisture from its surroundings and the absorbed water will be even more conductive. \$\endgroup\$
    – Sotto Voce
    Commented Jul 12 at 21:15
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    \$\begingroup\$ I'd be really worried about electrolytic activity even if the leakage current is acceptable. Liquid concrete is a dangerously strong caustic (similar pH to drain cleaner) and I'm sure a bunch of ions are left hanging around waiting for some moisture. AFAIK, SOP is to use thick PVC conduits. \$\endgroup\$
    – Spehro 'speff' Pefhany
    Commented Jul 12 at 21:56

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