The old way to lower an earth pit resistance was to pack it with salt and charcoal. A modern earth-enhancing backfill compound does the job better: it gives a lower, more stable resistance, does not corrode the electrode, and does not wash away - so the pit does not need re-treatment every year or two.
How they compare
| Factor | Compound vs salt and charcoal |
|---|---|
| Resistance | Compound lower and more stable |
| Electrode corrosion | Compound non-corrosive; salt eats the electrode |
| Wash-out | Compound stays; salt leaches away |
| Re-treatment | Compound none; salt pits need recharging |
| Standard | Conductive backfill covered by IEC 62561-7 |
