08.12.16
During use of a gas boiler, static voltage is generated on its body, which has a hazardous impact upon people and the electric equipment. The gas used for its operation requires reliability and responsible handling. A slightest accidental spark may result in a fire in the premises, so any residential house that has such equipment must be equipped with earthing.
It is not an easy task to design and mount earthing for a gas boiler, since a certain requirement is imposed upon its quality: the current spreading resistance shall not be greater than 10 Ohm. Many readers ask questions or request advice on configuration. We will answer the most popular questions.
Question: Is it possible to connect both earthing of the gas boiler and lightning protection to one earthing rod? What configuration should an earthing rod be: one point to 15 meters, or following the 3-point scheme of lightning protection? At which distance from the gas pipe should we bury the earthing rod?
Answer: It must be done that way. According to PUE 7-th ed. p.1.7.55 the earthing should be common. There are no requirements for the structure of the earthing device for protective earthing or for a gas boiler. If the all-in-one earthing kit ZANDZ ZZ-000-015 is installed at 3 points integrated by a horizontal band, it can be also used for lightning protection. However, there are requirements to the earthing resistance, which should be no more than 10 Ohm (EIC, PUE) 7th edition, par.1.7.103.
In such soils like clay, loam and black earth, the all-in-one earthing kit ZANDZ ZZ-000-015 will ensure 10 Ohm during assemblage at both 1 and 3 points. As regards the requirement for earthing devices in a lightning protection system, in this case the resistance is not normalized, and the structure is regulated by RD 34.21.122-87 п.2.26. There shall be at least 2 vertical electrodes of at least 3 meters long integrated by a horizontal conductor. The distance between the electrodes shall be at least 5 meters. The distance from the electrodes to the object at least 1 meter.
If you are planning to connect a gas boiler and the lightning protection system, it is necessary to comply with all the above listed requirements simultaneously. The distance to the gas pipe is usually set to be at least 2 meters.
In each particular case, a custom solution is possible. To know more about the earthing of a gas boiler, read here. Do you need assistance with calculations for lightning protection? Contact our Technical center ZANDZ.com!
Read also:
- Diagram for the connection of earthing in an out-of-town house IT earthing system
- Feasibile options for residential houses
- Earthing in lightning protection