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In principle, cadett ELSA does not distinguish between internal and external connections.

 

•An external connection is a connection between cabinets. That is the reason for calling it external.

 

•An internal connection is a connection within a cabinet. That is the reason for calling it internal.

 

There is no major difference between these connection types. In both cases it is a connection between two connection points.

 

On the other hand, what cadett ELSA really distinguish, are wires and cable cores:

 

•A wire is a sole conductor, for instance a RK.

 

•A cable core is a conductor within a cable that contains several conductors, for instance one of the cores of an ordinary EKK cable.

 

Symbols are connected with lines in the circuit diagrams. All such connections are by default interpreted as wires.

 

To define a cable, a so-called “cable symbol” is used. A cable symbol is used to turn a wire into a cable core.

 

With such a cable symbol, the item designation and type of the cable, as well as the cable core numbers, can be specified directly in the circuit diagram.

 

 

Strictly IEC-wise, cable information does not belong in a circuit diagram. Instead, it should be presented in a cable list or a cable core list. However, the cable symbol is a very practical aid, not the least to enable automatic creation of these cable core lists. For this reason, cable symbols are placed in separate cable layers, which makes it easy to hide the cable symbols, thus creating a documentation fully compatible with the standard. Of course, it is also possible to keep the cable symbols visible. That indeed constitutes a deviation from the standard but is nevertheless both practical and popular.

 

The cable symbol differs from other symbols in an important way. A cable symbol in fact only provides additional information about a connection, namely, to say that a certain connection should be interpreted as a cable core instead of a wire, and to give some details about that cable core.

 

A cable is not a device in the sense that for example a fuse or a motor is. Therefore, the cable symbol is not breaking the lines that it is placed on. The cable symbol is placed on top of the lines.