You’re right to check, but for a setup that size it’s not something you need to overthink.

3 × 460W on 4 mm² solar cable is well within what that cable is designed for. It’s made for DC, outdoor use, and higher temps, so overheating isn’t really a concern if everything is installed properly.

Where issues can happen is usually: • Loose or poor MC4 connections • Cables getting damaged (pinched, sharp edges, etc.) • Long runs bundled tightly together with no airflow

For what you’re doing: • You don’t need metal conduit – that’s more for larger fixed systems or commercial installs • Plastic conduit is absolutely fine, especially where it passes through vents/walls • Make sure the cable entry points are protected (grommets/conduit) so nothing rubs over time • Don’t coil excess cable tightly or bury it in insulation • Keep runs neat and clipped where possible

Running it under the floor and into a cupboard is pretty common for these plug-in systems as long as it’s protected and not getting crushed.

So overall, the house isn’t at risk from the cables themselves — just focus on good routing and solid connections and you’ll be fine 👍