Weather vanes, grounded or not grounded?

When planning the installation of your weather vane, the question arises, does the weather vane need to be grounded? I have designed grounding systems for the petrochemical industry for almost 50 years, and during that time I have designed some grounding and lightning protection systems. A construction site, be it a house, garage, barn, or whatever, can have multiple grounding systems. One main system is the electrical safety ground system. This is the wire that connects to a ground electrode, sometimes a water pipe, to the switch panel and runs to all receptacles. The electrical safety ground ensures a good ground connection that is required to trip the circuit breaker in the event of a short circuit. If you have a computer system, you may need to have a separate isolated ground system to prevent electronic noise through the ground system. The one we want to talk about now is the lightning protection system and its weather vane. An effective lightning protection system will have a series of lightning rods, properly spaced at the high points of the structure. The lightning rods will be connected to each other and to ground with copper or aluminum conductors. The lightning protection system helps drain negative ions in the air as it moves through the lightning rods, decreasing the likelihood of a direct lightning strike. Negative ions accumulate as air moves across the ground. This is similar to static electricity, like sliding your feet across the carpet and then touching something and drawing an arc, and as you know, the rays are more powerful.

In conclusion, I think your weather vane should Never be connected to your electrical safety ground or to the isolated ground of your computer. If you have a lightning protection system installed in your structure, then you must connect your weather vane to your system with an appropriate conductor. If you don’t have a lightning protection system installed, then a ground connection to your wind vane is not needed and it can even cause damage during a storm.