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Macros to insert earth symbols are found in the Symbol Insert Tool, under resource category d – Earth… as shown in the figure above.

 

Six different appearances of the Earth symbols are available.

 

▪Simplified Chassis Earth

▪General Earth symbol

▪Chassis Earth

▪Protective Earth

▪Noiseless Earth

▪Equipotential bonding

 

These are all earth symbols defined by IEC617.

 

When an earth symbol is inserted, it is automatically rotated correctly in relation to the line which it is inserted on. Therefore, it is not possible to insert an Earth symbol in “the air” and draw the line to it afterwards. You must start with the line and insert the symbol on the line.

 

Each one of the mentioned six earth symbols exists in two different variants. These variants are called “SERIAL earth” and “TERMINAL earth” respectively. The difference between them is how the symbols are interpreted connection-wise, or in other words how the resulting wire list will look like.

 

Six appearances each one available in two variants give a total of 12 earth symbols, which are shown in the figure above.

 

•All symbols that are connected to earth with SERIAL earth symbols will be considered as connected in a chain, in the same way as if ordinary potential reference symbols would have been used.

 

•If TERMINAL earth symbols are used, the earth connections are separated, and will not be in a chain. A conventional earth rail is an example where that interpretation fits well.

 

 

 

SERIAL earth symbols are in fact potential reference symbols. This means that all SERIAL earth symbols of a certain kind belong to the same electrical potential. You can specify the potential name when you insert the earth symbol. A dialogue box will appear for that purpose.

 

TERMINAL earth symbols are in fact connector symbols, like terminals. You can specify the connector name when you insert the earth symbol. A dialogue box makes that possible.

 

In both these cases, it may be suitable to stick to the guidelines that are given in IEC445.

 

The table below is a short summary of the guidelines in IEC445 concerning potential names for earth connections of different kinds.