We have labelled our equipment with code 39 bar code labels. The labels also contain the asset number and the Trust name. We use DYMO type machines to produce them, there not brilliant quality, but they seem to survive ok, and it's a portable system. Our electrical safety testers all have bar code readers, which saves us having to type asset numbers in.
I wouldn't introduce a labelling system without them. Most portable capture units will require them so be prepared for the future!