Extraneous Conductive Part
A conductive part that is not part of the electrical installation itself, but which can introduce earth potential because it is connected to earth or otherwise carries a risk of potential transfer — for example metal water, gas or heating pipes, metal building structures, or a reinforced-concrete floor. Extraneous conductive parts that come within reach of earthed installation components must, under NEN 1010, be included in the main and/or supplementary equipotential bonding to prevent dangerous potential differences during an earth fault. The distinction from an 'exposed-conductive-part' (a conductive part of electrical equipment that can become live under fault conditions) is essential: an extraneous conductive part is not itself part of the electrical equipment.
Bij een verbouwing constateert de inspecteur dat een metalen gasleiding door de meterkast loopt binnen handbereik van de aardrail; hij adviseert deze leiding met een aansluitklem in de hoofdpotentiaalvereffening op te nemen.
Kunststof leidingen (bijvoorbeeld PVC-waterleiding of pex-buis) toch meevereffenen 'voor de zekerheid' — een vreemd geleidend deel is per definitie geleidend; niet-geleidende leidingen hoeven niet in de potentiaalvereffening te worden opgenomen en onnodig vereffenen kan zelfs verwarring geven over wat wel/niet spanningvrij is.
See also
- → §411.3 / Praktijk Cathodic protection versus main bonding — why connecting a pipeline can defeat the protection it's meant to have
- → §411.3.1.2 Main equipotential bonding — which extraneous-conductive-parts must be connected (§411.3.1.2)
- → §414 SELV, PELV & FELV — the extra-low-voltage measure
- → §706 Conductive locations with restricted movement (§706) — working inside tanks and boilers
- → IEEE 80 / praktijk Ground enhancement material (bentonite, conductive concrete) in high-resistivity soil — when extra earth electrodes are not enough
- → §543 (IEC 60364-5-54) Sizing the protective conductor — the adiabatic formula versus the simplified table