Replies

1. 
   jonny_h | Jun 30, 2021 10:16am | #1

   Here's a few thoughts that may vary depending on what stage of construction / planning you're in:
   1) In the design stage, make sure you have roof surface(s) optimally oriented for solar. This means looking at the ideal angle for your latitude and weather patterns, and also aimed ideally south (northern hemisphere, north in the southern hemisphere) or at least southeast / southwest. (Alternately, if you have a flat roof, you can use racking to set the angle) Also, on the roof surfaces that you want to install solar, make sure to minimize "bumps" -- no plumbing vents or attic vents, skylights, dormers, valleys, or other random roof plane changes.

   2) Yes, running conduit from the location of the main panel to the attic is a start. If possible, I'd go two steps further: First, (assuming a pitched roof), have the conduit brought to a flashed junction box (like a SolaDeck) put in at the same time as the roof is installed. (Ideally, if you can do a preliminary layout, you could also have all the rack mounting points installed when the roof goes on, too). Second, look into what the solar disconnect requirements are in your area -- you may actually want to run the conduit to somewhere near where your utility meter is located in order to place a solar disconnect outside next to the meter. (There's a lot of intricacies and local differences here depending on your intended setup, so it's hard to say exactly what you'd need)

   3) Ensure that the panel itself is capable of handling the capacity of the solar array you want. Again, there's several different ways to handle this, and smaller arrays are easier to handle than larger arrays -- but things like the busbar capacity vs. the main breaker capacity start to matter. There are some "solar ready" main panels that provide alternate / additional connection options to ensure the sizing requirements for solar are met.

   In short, it's hard to say exactly what to do without knowing more about your location / utility requirements, house, and intended solar plan (microinverters or central inverter? strictly grid-tie or providing for battery backup? etc...). But, in addition to just getting a conduit in the wall, I'd suggest (a) looking more into the exact electrical requirements and making sure your main panel can meet them and that you've provided access for any required disconnects (as well as space for any ancillary solar equipment), and (b) getting the conduit, and if possible racking mounts, built into the roof when the roofing is installed to minimize disturbances later.

   In terms of costs, the materials for these kinds of things would be a small percentage of the cost of the whole solar system -- but I can't speak to labor costs. I'd think, though, that paying a bit more up front could potentially save a lot more in the future by making the install substantially easier.

1. 
   arnoldk | Jun 30, 2021 10:41am | #2

   Hi Jonny,

   Thank you for the in-depth response. We have not yet started to house build which is why I am going through the construction plans to make sure I have accounted for everything I will need during construction or for future projects.

   I have reached out to a couple of company to find out what the cost would be for around a 7 kW system. The plan is the be grid-tied and I like the idea of microinverters though I suspect they do cost a bit more.
   We will be installing a metal standing seam roof which has connectors which clip directly to the standing seams, reducing additional penetration.

   For the conduit, is EMT or PVC most commonly used from the attic to the utility room? I know this vary a bit from location to location.

   Thank you,
   Arnold

2. Expert Member
   BILL WICHERS | Jun 30, 2021 12:16pm | #3

   >"For the conduit, is EMT or PVC most commonly used from the attic to the utility room? I know this vary a bit from location to location."

   Use EMT conduit here. Metallic conduit offers shielding (better for RFI), and most importantly is much better if you ever have a nearby lightning hit since the solar panels are like antennas for lightning energy. EMT does cost more, but the difference isn't as much as it once was at the moment since PVC prices have skyrocketed this year (there is a global shortage of PVC resin).

   Check with whomever you have doing the solar system design to find out what size conduit you need, and if you need more than one.

   You might want to have your roofer flash in some hard points for mounting too, but you really need to know more about what your final system will be to be able to specify where those hardpoints need to be.

   Bill

3. Expert Member
   Akos | Jun 30, 2021 10:35pm | #4

   I would check with your local utility on what type of system they allow. For example, a feed in tariff setup requires a 2nd meter base for the generation meter, this is cheap to add in at the start but cots a fair bit to swap out down the road.

   Even without PV, if you are in the land of ADUs or basement suites, a two gang meter base might be a good idea.

4. GBA Editor
   Kiley Jacques | Jul 01, 2021 11:29am | #5

   In terms of the roof, this article might be of interest to you:
   Designing for Solar Power.