If you look in the deep underbelly of AutoCAD Electrical you might stumble into one of the folders where it stores all its CAD blocks which get used for your Electrical schematics.
When you discover these files they will make absolutely no sense. Instead of seeing words like Capacitor, relay, pilot light etc. you will find a combination of letters and numbers. For example HPB12M. So what does this mean and why is it represented in this fashion?
All these letters and numbers tell AutoCAD Electrical what it is about and how it should interact with the other electrical components it is being placed with in the drawing.
The first character will always be either H or V. This tells AutoCAD if the insertion of this component is going to be horizontal or vertical.
The next 2 characters describe the type or family name of the component. PB stands for Push Button, CR stands for Control Relay, LS for Limit Switches etc.
The fourth character will either be the numeral 1 or 2. 1 signifies that the component is a Parent Symbol (think Relay) and 2 would signify that the component is a Child component (think Contact)
If the symbol is a contact then the fifth numeral would signify if it is normally open (NC) or normaly closed (NC). 1 is NO and 2 is NC.
If the 4th character is zero, it confirms to AuutoCAD Electrical that the wire passing through that component does not get a wire number change.
The last character is random to keep the naming convention unique.