We have our first permit in for a residential roof top PV system install. This is my first review of one and need some guidance. Besides requiring a one line diagram of the install, cut sheets on all related equipment, what other things should I be looking for? Off the top of my head I can think of a few: Structural analysis of the current roof to verify it can handle the array(s), elevations showing where the arrays will be mounted on the roof in relation to ridge and eaves, get FD involved to approve install, get City owned utility involved for possible net metering, others? I understand all components need to be listed/UL listed, does this also include the racking system that supports the panels? Lots of questions, I know. Just want to make sure I am covering my bases. Thanks
Requiring a structural engineering stamp on every design is a big burden for installers and I would encourage you to adopt a formula that allows for approval without requiring that. A number of AHJs we work with have standard forms on which we certify that the existing structure meets their required standards, which are pretty much that they meet the current code for rafter spans. In other words, on older homes where we find overspanned rafters, we upgrade by sistering a larger rafter or adding strut or purlin support to a load bearing wall. On homes that meet current code we don't have to. Some AHJs require a section drawing of the attic with dimensioned rafter spans, some just have us fill out a form. The structural PSF load for PV systems is typically under 3PSF which is not that much. We always provide PSF and point load calculations with our plans. Some AHJs have a limit on point loads (e.g. 40lbs per attachment), above which they require an engineering stamp.
Besides a line diagram, our plansets include a site plan, roof plan, and mounting detail, but not an elevation. An elevation is something that we pretty much never do for any AHJ (except one that has a complicated local building height limit ordinance). However we do include a mounting detail that shows whether the modules are mounted flat to the roof, or tilted up, and the height above the roof. A full building elevation is asking too much in my opinion. Things like fire access pathways can be shown on the site plan.
How you involve your fire department is up to them and you. A few AHJs we work with require fire department review, but most simply check for fire setback guidelines at the building department. But since this is your first, you should review with the FD what the requirements are and decide who will approve those aspects.
Racking systems or accessory components may be listed for electrical grounding; most are nowadays, and we don't put lugs on every module for grounding anymore. Other engineering aspects of the racking systems are not subject to UL standards but any reputable racking manufacturer will have specifications and data available for you to check if the product is being used properly. Different rails and systems will allow for larger and smaller spans between mounting points.
Hopefully your local utility has already set up a process for approving net metering that shouldn't have to involve anything besides your normal duties. Large utilities usually just ask for the approved building final before approving interconnection.