NEN 1010 §542
Main earthing electrode
Hoofdaardelektrode
Also known as: grondpen, grondplaat, earth-electrode, aardpen
Ground electrode: conductor in the earth (rod, plate, loop, or foundation earth) connecting the installation to the earth mass. Requirement Re ≤166 Ω for TT with ALS 30 mA, often much lower via a foundation earth (ring earth around the foundation).
Practical example
Main earthing electrode. In a TT installation with a 30 mA RCD, a ground resistance of 80 Ω is measured via the foundation earth, well within the ≤1666 Ω requirement.
Common mistake
Main earth electrode Common mistake: Assuming an old, corroded earth rod without remeasuring resistance — actual Re may have risen significantly due to corrosion and soil drying.
See also
Related terms
- Main earthing terminal
- PE (Protective Earth)
- Earth electrode resistance measurement
- TT system
- Plate Earth Electrode
- Connection capacity / contracted power
- Fire-Protection RCD (300 mA)
- EV charging point (Mode 3)
- Foundation earth electrode / ring earth electrode
- Mobile or Transportable Unit — Electrical Provisions (§717)
In-depth guides
- → Earthing and earthing systems (TN, TT, IT)
- → §542 / IEC 60364-5-54 Sizing an earth electrode — the calculation formulas for rod and plate electrodes
- → §542 Earth Electrodes — Foundation Earth Electrode, Rod and Ring Electrodes (§542)
- → §542 (elektrodemateriaal) Galvanic corrosion of earth electrodes — material choice copper versus steel
- → §411.5 (IEC 60364-4-41) The TT system — why an installation's own earth electrode makes an RCD mandatory
- → IEEE 80 / praktijk Ground enhancement material (bentonite, conductive concrete) in high-resistivity soil — when extra earth electrodes are not enough
- → §542.4 (IEC 60364-5-54) The main earthing terminal (§542.4) — why every connection must be individually disconnectable for measurement
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