electrical diagram symbols

[JtotheJ]

https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwiOpe6RoaTZAhVK0WMKHQMcAl8QjRwIBw&url=https%3A%2F%2Fwww.electrical-symbols.com%2Felectric-electronic-symbols%2Felectrical-transformer-symbols.htm&psig=AOvVaw0xfu6D8BNVasDpedSnRbEJ&ust=1518658291787989

why does the test ask what the symbol above is but it's not in the electrical one line diagram symbols?

https://testguy.net/content/219-Electrical-One-Line-Diagram-Symbols

[EEBSMSPE96]

https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwiOpe6RoaTZAhVK0WMKHQMcAl8QjRwIBw&url=https%3A%2F%2Fwww.electrical-symbols.com%2Felectric-electronic-symbols%2Felectrical-transformer-symbols.htm&psig=AOvVaw0xfu6D8BNVasDpedSnRbEJ&ust=1518658291787989

why does the test ask what the symbol above is but it's not in the electrical one line diagram symbols?

https://testguy.net/content/219-Electrical-One-Line-Diagram-Symbols

I've been doing this for 30 years and I've never seen one document with all possible electrical symbols in it. It seems that every Utility, Industrial Plant and Engineering Firm has their own unique library of electrical symbols with many different variations of standard symbols in it. Even IEEE Standard 315 for electrical and electronics graphic symbols doesn't have every electrical symbol that I've seen used in my 30 years.