The following notes relate to BS 7845:1996 ..Guide to the use of BS 3939 and BS EN 60617
A block diagram is a simple diagram in which an installation or equipment system together with its functional relationships are represented by block symbols or outlines with annotation without necessarily showing connections.
Circuit diagrams are completed to show the full functioning of a circuit showing all its essential
components and connections by means of graphical symbols. It shows the
operations without necessarily showing the physical layout.
A connection diagram shows all of the connections between components. This diagram assists
in the actual wiring of circuits.
An interconnection diagram represents the connections between the different units of and installation. Its purpose
is to show the external connections of a unit. The internal connections are shown on a wiring diagram.
Links Providing information on Drawing Diagrams and