A stackable moulded junction box section, suitable for construction of underground junction boxes. The section includes integrally moulded support means (55,56,57). The support means can comprise a step (52) and can also comprise a receiving means (56,57) for receiving and supporting a support (58), which may be moulded integrally with the section and then separated for use. The section may comprise inner (50) and outer (51) walls joined by cross-reinforcement portions (52) which divide the space between the walls into cavities (53). Provision to form apertures between the cavities, which may comprise a knock out portion (54), can be provided. The apertures may be open to the bottom of the section, so that the section may be placed over a conduit. The section may include projections to enable it to be stacked on end. In another embodiment the section is formed from two or more separate interlocking components.