I have always struggled with which symbol to use.  Even when IEC 60617 was current we had issues.  My field is Machine Tools so we have a combination of Electronic, Electrical and Electro-mechanical.  The pace of evolution of equipment has been fast.  There is another poignant fact that muddies the water as well, we used technology from all over the world.  When symbols are created they are invariably based on the local prevailing 'Standard', actual or company.  When viewing older machine tool electrical drawings, Machine tool companies made up their own symbols for their preparatory parts ( it's a black box ! ).  Then there were companies that supplied major components who did the same.  Some of these symbols stuck as the brands were dominant or stuck in certain markets and not others.


In an ideal world, the IET would sit down and create a Standard and a standard method for creating new symbols.  This is not practical.  There are lots of projects like this that have proved to be too big and impossible to complete.  Just look at the Guidance of machine tool guarding that the HSE started to undertake, well before the Machinery Directive.  They started creating guidance for each type of machine, they only covered a small number of the actual variations and then they were out of date very quickly as the machines and technology moved on.  These guidance documents are still around and causing confusion, with the advent of faster more complex machines and functional safety requirements they are now dangerous in many instances if applied. 


If we take lessons from history, it makes sense to have IEC 60617 free to have and use and is a good starting point and allows new generations to understand a common base.  Then we have to design our own new symbols based on that IEC 60617 foundation.  As long as we have a table of symbols in the appendix of our drawings then our drawings can be understood and used safely, but this only applies if we can have, use and reproduce the IEC 60617 symbols freely.


It is a case of understanding the fundamentals and applying them, building on good foundations.  Directives and Standards can help with this.  Conversely,  Standards can prohibit this, they cost a lot especially when it very quickly becomes apparent that there are multiple required for even a simple project. The people that need then the most, the new engineers, the innovators or those using ideals from a field outside their own might not have access to them.

IEC 60617 is still current - I guess you're getting at the fact that it costs a packet to subscribe to ... and when you read into it, it's not the end of the line because there are additional symbols in other standards for fire, security, P&ID, etc.?


We've definitely had a few goes at this discussion in the past, to name but a few:

• https://www2.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=16776

• https://www2.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=25910

• https://www2.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=25910

• https://www2.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=45307

• https://www2.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=107335