Although the European standard for DC wire colors is Brown for +DCV and Blue for -DCV, the unofficial American "standard" is to use Blue for +DCV. The -DCV wire is usually White with a Blue trace, or Blue with a White trace.

 

If it were only that simple - http://www.control.com/1026198845/index_html

I believe that the lead you identify as -DC is actually DC common.

 

Perhaps you would like to join All About Circuits and even publish (or at least name) the standard you are talking about

My reading of EN60204-1 is different from yours.