These questions are adressed in the article 164 of the RGIE (Règlement Général des Installations Electriques). Further information can be found at the site of the Belgian FPS Economy, SMEs, independent Professions and Energy (partially developped in English, complete in French and Dutch, tab Energie – Electricité – Contrôle des installations électriques).
The company that owns the line must of course respect these standards. In case of a building under an existing line, the builder must also respect these constraints.
If you would like an answer independent from the transmission system operator, you should contact an inspection, verification, testing and certification company. You can also contact your electricity supplier (see your electricity invoice).
The distance between the cable and the roof depends on the voltage of the line and of course on the location of the house along the span, and also the ambient temperature, the sun and the wind. An additional safety distance is also adopted in case of overvoltage. When introducing a new regulation, the more critical case is considered, i.e. maximal load in the line, maximal insolation (around 1000 W/m2), maximal ambient temperature and a low wind of 0.6 m/s.
For example, according to the article 164 of the RGIE, the minimum distance between the roof of a house and a low voltage line (400 V) is 2 m. The higher the voltage of the line is, the higher the distance will be.
En Belgique, à ce jour, il n’y a pas de réglementation en rapport avec une limitation d’implantation de maison. On peut donc s’installer juste en dessous d’une ligne.
Les limitations règlementaires concernent les distances de sécurité verticales et horizontales à respecter en cas de proximité avec une ligne. Elles sont fixées par le RGIE (article 164) en fonction du niveau de tension et de quelques paramètres – voir des informations sur le site du Service Public Fédéral – Economie, PME, Classes moyennes et Energie / Onglet Energie – Electricité – Contrôle des installations électriques).
Vous trouverez également plus d’informations à la page Normes.
This authorization varies from country to country. In Belgium, in consideration of population density (one of the highest in the world), it is possible to build a house under a powerline.
Safety distances are imposed by RGIE / AREI (*) (Règlement Général des Installations Electriques / Algemeen reglement voor elektrische installaties) and can be obtained on demand to the electrical society (Elia in Belgium) that is responsible of the line. It depends of course of the voltage of the line but also of the conditions of installation (sag of the conductor in case of maximale temperature).
If you construct such a building, it is essential to design your wiring strickly in compliance, especially by installing an excellent ground wiring, by the grounding of all metallic structures (heater, pipes, drainpipe…). We advise you to consult a certified organization.
(*) http://economie.fgov.be/ (in French or in Dutch)
(Energie – Electricité – Contrôle des installations électriques)
(Energie – Elektriciteit – Controle van de elektrische installaties)