When three or more planets are 120 degrees from one another in three parts of the
birth chart, they form a triangular configuration called a grand trine. Usually, the planets are in the same
element (
Fire,
Earth,
Air, or
Water), and the formation is described, for example, as a "Fire" or "Earth" grand trine. This pattern shows special protection and can be beneficial, although it does indicate a closed circuit of energy. It may also show areas where the person is self-sufficient.
SOURCE: The Truth About Astrology, Gloria Star