A module includes a parallelepiped main body having four lateral faces extending between an upper face and a lower face, in which an inner chamber is provided in the main body, opening in the top and bottom faces in order to receive, on the inside, a distribution or regulation device. The inner chamber includes, consecutively, an upper bore, an intermediate bore that has a smaller diameter than the upper bore, and a lower bore that has a smaller diameter than the intermediate bore. A plate is provided on each lateral face for attachment to a plate of a similar adjacent module, the plate having peripheral holes used for the passage of attachment screws and a central blind hole suitable for guiding a drill hole opening in the upper bore or in the intermediate bore.