Hey everyone! I'm currently in the process of building a new home, and I've designed it with a large south-facing roof for future solar panel installation. My plan is to first move in, monitor our energy consumption, and then size the solar system accordingly. To keep the exterior looking clean, I'm considering running conduit through the walls from the attic to the basement now, or even just installing holes with string. I'm anticipating that the future system may be around 15 kW and am open to options like micro-inverters or an all-in-one unit with batteries in the basement. However, I'm unsure about how many wires I would need to run and what size conduit to install. Any advice would be great!
3 Answers
For your conduit, I’d suggest using 1.5” for the run from the roof to the sub-panel. That should give you enough space for the wires you'll need.
I recommend running more conduit than you think you'll need—maybe three times the amount. Also, adding junction boxes on the main level can be really handy for future needs beyond just solar. You never know how useful those conduits could be in a few decades!
According to NEC regulations, it's important to use metal conduit for solar wires inside buildings, like EMT, which is pretty straightforward to install. Also, consider how to effectively firestop inside the conduit, especially between different floors. A good tip is to place accessible junction boxes at floor transitions so you can easily apply firestop putty if needed.
Got it! If I’m running a straight line from the attic to the basement, is it feasible to set up a string pull for future wires? I'm curious about how to handle firestop in that case.
Absolutely! While it can be a bit of an investment in CPVC, spending a little now will save you a lot of headaches later, especially if you want to reconfigure things down the line without having to create new openings in finished walls.