Earthing system for electronic appts. - uses screened lead in bore-hole to avoid earth-surface currents

摘要

The system makes contact with a stratum, below the upper strata, which is free from currents flowing through upper strata. An earthing point is connected to a screened leade which is fed down a bore-hole in the earth. When the lead reaches the required stratum, the screening is removed and terminated in its characteristic impedance. The unscreened section of the lead is connected to a weight making contact with the bottom of the bore-hole.