Roof stand
A roof stand is a small overhead line mast that stands on a house roof .
Power supply
In residential areas with overhead line supply, an overhead line for power supply from house to house is often stretched over roof stands . From around 1970, the power supply in new building areas in Germany is mainly provided via underground cables , but overhead lines are still to be found in many older residential areas, especially in rural areas. Laying underground cables is much more expensive.
In addition to greater susceptibility to failure and higher maintenance costs (e.g. regular pruning of trees), the appearance of the roof lines is also a disadvantage. Lightning protection is a major problem .
To supply the respective house, a tap on the overhead line is led into the house through a cable inside the roof stand. Usually three outer conductors and the PEN conductor at 400 or 230 V are used (see also three-phase network ). However, more conductors can also be laid, for example to also supply the switched street lighting .
Telecommunication technology
Roof stands for overhead telephone lines no longer exist in Germany today.
Higher tensions
Overhead line masts for higher voltages are not designed as roof stands, since the static requirements of such masts exceeded the load-bearing capacity of the roof structure due to the higher safety distances.
An exception are the high-voltage lines from the Kozienice power plant , which are laid on roof stands on the power plant roof. This is justifiable in this case because this building - and thus also the roof - can only be entered by specialist staff. However, in the case of such roof stands, because of the high static requirements, the construction still extends far into the building, and there can even be an independent mast that is located inside the building.
A roof-post-like construction of a traction power line can be found in Germany as mast No. 9108 in a shed in the goods station in Fulda . However, it is not on the roof, but on the floor inside the shed; it is therefore not a roof stand.
