Cable routing

Cable routing is a single switch in the Inspector — Calculate AC cable trench. When it's on (and your plan allows it), SolarLayout places DC string cables, AC home-run cables to ICRs, and the shared AC trench corridor, and reports the cable bill of materials in the PDF and CSV exports. When it's off, no cables are drawn and generation is faster.

When to turn it on

Turn Calculate AC cable trench on when:

• You're producing a BoQ or BoM that needs cable lengths.
• You want the PDF report's cable section populated.
• You're comparing plant designs where cable cost matters.

Leave it off when:

• You only need capacity and energy yield numbers (first-look estimates, parcel screening, early-stage BD work).
• You want the fastest possible generation. Cable routing adds meaningful compute time, especially on large multi-plot projects.

Where to find the switch

The switch is in the Inspector → Plant Layout tab, under the Site section, labelled Calculate AC cable trench. On Free plans this row shows a "Pro" chip and the switch is disabled — cable routing is a Pro-plan feature.

Change the switch before clicking Generate layout. Changing it after a layout has been generated doesn't re-route the cables for that result — you need to click Generate layout again.

What gets placed when it's on

With Calculate AC cable trench on, the layout includes:

• DC string cables from each string of modules to its assigned inverter.
• AC home-run cables from each string inverter (or central inverter SMB) to its ICR.
• The AC trench corridor — a single shared trench / cable-tray path through the plant, computed as a minimum spanning tree over the inverter and ICR positions. This is what the EPC civils team digs once.

The PDF report's cable section lists:

• Total DC cable — sum of per-string copper lengths.
• Total AC cable (copper BoM) — sum of per-inverter home-run copper, what your procurement team orders.
• AC trench length — the physical corridor length; usually considerably shorter than total AC copper because the corridor is shared.

CSV exports include the per-cable detail you need to load into a BoQ spreadsheet.

What it costs in run time

Cable routing adds compute time on top of the layout placement step. On a typical 50 MWp single-plot project, expect a few minutes of additional generation time compared with the no-cable run. On large multi-plot projects, it scales with plot count and table density.

If you're iterating on table parameters (tilt, GCR, table size) and only care about capacity, leave the switch off — you'll iterate much faster. Turn it on for the final pass once the layout shape is settled.

What gets placed when it's off

With Calculate AC cable trench off, the layout still includes:

• Module tables.
• ICRs.
• String inverters (in string-inverter mode) or central inverter positions (in central mode).
• Lightning arresters.
• Perimeter road and setbacks.

The PDF report's cable section reads Cable routing skipped and the cable BoM rows are empty. You can re-run the project with the switch on later — the previous result stays on file under the Inspector's Runs list.

Multi-plot warning

On multi-plot projects with Calculate AC cable trench on, the Inspector shows a small pre-flight notice. Cable routing is plot-local — each plot's cable trench is computed independently within that plot's boundary. There's no inter-plot trench in v0.1. If your civil design needs a shared inter-plot corridor, you'll need to add that on top of what SolarLayout produces.