I have a problem with autocad electrical, I would like to change the layer color "wireref" but for my entire project portfolio in all my 20 same time and not one by one, the command line can be?

Thank for advance

I don't think it can be done all at one time.  I think you would have to do it sheet by sheet.  Maybe you could write a script that you could then use to batch process all 20 drawings.