Strings per inverter input
The plan starts from each roof face that has panels: the rows from the eave up, the panels along the eave, the face's tilt and azimuth. The inverter is the one in the selected installer's package; without one, a reference profile sized on the array's STC watts is used, and when the layout does not fill its inputs the plan steps to the next larger profile, at most 3 times, and records each step. An installer's inverter is never swapped. The result is a set of strings per MPPT input with their panel count, voltage and current, checked against the inverter's start voltage, MPPT window, maximum DC voltage and input currents.
Strings that follow the shade
With the sun, the trees and the obstacles of the roof as an environment, the panels are grouped by shade over the hourly tables of the year, so one shaded panel does not pull down a whole string. The plan then reports the electrical yield of the chosen string count against the ideal and the plain geometric grouping, one row of options per possible string count, and the mismatch loss of each string from the model instead of a rule table. Micro-inverter and per-panel MPPT plans have no string count to choose: every panel has its own MPPT.
Cables round obstacles, least cable in series
Each face's chimneys, skylights and other obstacles are projected onto the roof plane, and the jumpers between panels and the home-run legs down the slope are routed round them with 0.1 m clearance, so the metres in the table are the routed ones; a detour longer than the module leads adds its extension cable. Within a string the series order and the two end panels are the ones with the least cable, and the plan says how many metres that saves against the plain row order. One face of 110 panels with 10 obstacles plans in about 30 ms.
Design temperatures by latitude
The cold check uses the open-circuit voltage at a design minimum that follows the house's latitude: −25 °C south of 60° N, −30 °C from 60° to 64° N and −35 °C north of 64° N. The hot check uses the maximum-power voltage at a cell temperature of 70 °C for a flush roof mount (65 °C for a tilted one). Both are compared with the inverter's limits, and the report shows the June and December voltage frames.
The stringing report and the single-line diagram
The stringing report PDF lists every number of the wiring pane: each string's panels in series order with the roof diagram, Voc and Isc at both design temperatures, cable lengths, the inverter's limits, the assumptions, the standards and the disclaimer. It is rendered once per plan version and cached; a new run or a scene edit makes a new version. The wiring template adds a single-line diagram per inverter with strings and panel counts, protection, cable types and lengths, battery, EV charger and the grid, and applies one DC switch-disconnector per inverter that isolates every used MPPT input at once, per SS 436 40 00 and IEC 60364-7-712.
All of this is a planning estimate. The registered electrical installation company makes the final design, selects the protection and cables and is responsible for the installation; the report's protection values are marked as suggestions.
