The good news for engineers at CERN is that a part of the massive particle accelerator known as the Large Hadron Collider is getting an upgrade. The bad news: getting the job done isn't easy.

The cables are being removed as part of CERN's LHC Injectors Upgrade Project, scheduled for 2019. Three injectors — which assist in accelerating particles before they enter the Collider — each have approximately 3,000 unused cables. A team of 60 engineers has already started identifying those cables, using a database and manual check-ins, ahead of a plan to begin disconnecting them during a "technical stop" at the end of this year. Fully disconnecting all of the cables will take four years.

As Motherboard reports, pulling the wrong cable could lead to major problems with the Collider. It sounds a bit like defusing a bomb: pull the right wire and you're in the clear, but pull the wrong wire, and in this case, you might have a very expensive, very broken piece of machinery.