The previous British colours, switching to current European.
For anyone who has not been paying attention in class:
Previous British = Red/yellow/blue phases, plus black neutral.
New European = Brown/black/gray phases, plus blue neutral.
From C-H's link:
‚ÄúThe change was made‚Ä¶to create a single European market for cables,‚ÄĚ explained Hodge.
But there are still cable types used in the U.K. but not in Continental Europe and vice versa.
Safety was considered an issue as companies and individuals operating across different countries in Europe previously used different colour coding systems.
And those different systems will still be in use for decades to come, plus we now have the new system to add to the collection.