PVC conduits are acceptable when used properly (lots of expansion joints). Metallic conduits (EMC, IMC, RGS) are more expensive, but should be in areas subject to physical contact with other items (such as riser up walls, in electrical rooms, etc)....

Solar arrays are valuable revenue generating assets that require a certain amount of maintenance. How much exactly depends on what type of installation we are talking about (ground mount vs. roof mount), the size of the installation (obviously...