This logo symbolizes neutrality (convergence of the three branches) and ground.
Many things come in threes: the three branches of government, the saying ``three's a crowd'', and so on.
In the Marshall McLuhan sense, we live in the electric age where we wear all of humankind as our technological clothing.
Electricity also comes in threes. The three phases of electricity are denoted using the standard colours red, black, blue (section 4-036 of the electrical building code). Neutral, at the center of the three phases, is denoted as white. Ground is denoted as green, and is underlined with the universal symbol for electrical ground. The grey background is the typical grey of breaker panels and electrical boxes.
In movie production sets, you can often see the five wires for electricity running along sidewalks, down the hallways, across roads, etc., in the colours: Red; Black; Blue; White; and Green. In a circuit breaker panel, the 3 "hot" wires coloured: Red, Black, Blue (in that order) usually come into three rails that run up through the panel, with the phase angle between any two of these rails being 120 degrees (e.g. as symbolized in the logo above). Neutral is a white wire. Ground is green or bare copper (which turns green as it oxidizes over the years), and connects the metal frame of the breaker panel to earth, usually by way of a copper pipe (which may also turn green in time).
Electricity is at once both nostalgic and modern, symbolizing both the past and the future.
McLuhan often said that we live in the electric age, and that the computer is our technological clothing. McLuhan spoke of clothing in the electric age as a metaphor, but soon we will actually wear or implant our computers on or in our bodies, which themselves use electricity as a signalling medium. Whether by wires, or wirelessly, we communicate, interact, and live by electricity itself, or by electricity in the form of electromagnetic radiation. But at the same time, we run the risk of lost opportunity if the industries and researchers of the electric age fail to agree on standards, fail to collaborate, and fail to recognize and appreciate each other.
The rivalries among those who could best design the technological clothing of the future may greatly delay progress, in the same way that the disputes between Edison and Westinghouse greatly slowed down the widespread use of electricity itself.
In the politically charged climate of today's technological world, we need to find a Neutral Ground!
Usage of the Neutral Ground logo.