What types of cables should I use for fixed wiring inside walls during an electrical upgrade?

For concealed fixed wiring in walls, building wires such as H07V-U or H07V-R with a thermoplastic PVC insulation are commonly used. However, to enhance fire safety, always choose cables with a Construction Products Regulation (CPR) Euroclass of at least Eca, though B2ca or Cca offer significantly better reaction to fire performance. These cables must meet EN 50575 and carry a CE mark along with a valid Declaration of Performance (DoP) that confirms their flame propagation, smoke production and flaming droplet characteristics, ensuring compliance with EU Regulation (EU) No 305/2011.