Why does a chimney made of bricks need a lightining conductor and not a steel chimney of the same height
Answers
A steel chimney is conductive and likely tied to ground in the building foundation, though it is standard practice to bond all metallic components on a roof to a common loop conductor that is grounded in any lightning protection system. A chimney made of brick is not considered electrically conductive. However, if it is wet it may be able to conduct some electricity from lightning to ground and it is suceptable to lightning strikes due to its prominence on the roof. This is dangerous because since it is not a true conductor, electricity will always find the most conductive path to ground and may flashover to adjacent structures or even people if they create a better path to ground. This causes a potential electrical hazard during a lightning storm. Adding an air terminal or lightning rod to the top of a non-conductive chimney is a safe way to channel all lightning strikes from the chimney safely to ground with a much lower likelihood of dangerous flashovers.