Depending on the type and size of system you want the conduit details will be different. But to be safe, you should only need 2x 1" conduits (enough for 20kw worth of array easily) but they need to be metallic, either emt, metal flex, or galvanized rigid conduit. We run emt inside building almost always. The reason for metallic conduit is because if you a string inverter system, then the wires in the building will have DC voltage, and the national electric code(NEC) requires DC wiring in a house to be in metallic conduit. The 2014 NEC now has a requirement for a rapid shutdown feature, which MIGHT require a separate conduit for signal wires to go to the array and sever the DC connection at the roofline. So an additional 3/4" PVC conduit might be a smart idea as well. In reality the 2014 NEC is so new, that there is no real standard solution for the rapid shutdown requirement, but as you are planning for the future, 3/4" PVC is super cheap insurance. Using micro inverters solves the issue, but the is no guarantee that micro inverters will be the best fit for your site, so it goes back to adding the cheap insurance... |