Solar design automation, without the hand-waving
Every vendor says “automation.” This page says what the word actually covers in a solar construction document set, what to automate first, and the three honest ways to get there — including the two we sell and the one we teach for free.
The definition
Automation does the drafting. The engineering stays yours.
A commercial solar drawing set contains two kinds of work. The first is judgment: equipment selection, conduit and OCPD sizing, SLD content, AHJ-specific details — the work a licensed engineer owns and stamps. The second is mechanical: placing strings inside temperature-corrected voltage windows, routing homeruns, generating tags, exporting cable lengths, filling schedules. The second kind consumes drafting hours on every single project and is drawn the same way every time.
Solar design automation is software doing that second kind of work — with the arithmetic shown, so the first kind can check it. A tool that hides its numbers is not automation an engineering firm can use; it is a liability with a progress bar.
Automatable: stringing, homerun routing, NEC conductor arithmetic, circuit-length export, tagging, schedule tables, SolarEdge Designer PDF import.
Not automatable: the stamp, the judgment behind it, and anything an AHJ will ask a human to defend.
Three honest paths
Write it, install it, or type it.
1. Write the tools yourself
Python or C# against the AutoCAD API gives you exactly the automation you design, at the cost of building and maintaining it. We publish the full recipe free, because an engineer who understands the automation reviews it better: start with Python for AutoCAD or C# and Visual Studio, then the 200-line solar stringer.
2. Install the finished tools
Branch ships the stringing, homerun, tagging, schedule, and SolarEdge-import tools inside AutoCAD 2018–2026. Flat $299/mo per daily active user, no seat limits, 14-day trial. This is the path for teams that want the drafting hours back this month.
3. Type what you need
Leaf Automation Studio runs real drafting tools in the cloud from a plain-English prompt — describe the task, review the result, keep the tool. Runs are Leaf-hosted, you confirm before anything executes, and the authoring-and-export path is being built in the open with the evidence published. Demo mode works in the browser without an account.
The sequence
How to automate a solar drafting workflow.
1.Inventory the repeatable drafting tasks
List what a drafter redraws on every project: strings, homeruns, tags, schedules, cable lengths. Anything drawn the same way twice is a candidate; anything requiring judgment stays with the engineer.
2.Automate stringing first
Stringing is rule-bound and high-volume: module counts and NEC 690.7 voltage windows are mechanical once equipment is chosen. Verify the tool shows its arithmetic so the engineer can check it.
3.Add homerun routing and cable schedules
Route homeruns from string endpoints to inverters or combiners, then export circuit and cable lengths to a schedule. This is where drawing data starts feeding engineering analysis instead of being retyped.
4.Keep the review step explicit
Every automated output needs a human acceptance step: what ran, what changed in the drawing, and the numbers behind each result. If a tool cannot show that record, it cannot be reviewed, and unreviewable output does not belong in a stamped set.
5.Only then generalize
Once the per-project tasks are automated, look at the workflow between projects: reusable company tools, templates, and standards. Automating a broken process just produces wrong drawings faster.
Straight answers
The questions engineers actually ask.
What is solar design automation, concretely?
It is software doing the repeatable drafting work inside a solar construction document set: placing strings within NEC voltage windows, routing homeruns, sizing conductors with the arithmetic shown, generating tags and schedules, and exporting circuit lengths. It is not software making engineering decisions — the engineer sets the inputs, reviews the output, and stamps the set.
What should a solar engineering team automate first?
Stringing. It is the highest-volume, most rule-bound drafting task in a commercial set: module counts, temperature-corrected voltage windows, and layer discipline are all mechanical once the engineer picks the equipment. Teams that automate stringing first typically recover hours per project before touching anything else.
Does automation replace the engineer of record?
No. Automation produces drafting objects and cited intermediate calculations. A licensed engineer reviews, corrects, and stamps the set, and owns every judgment call — conduit, OCPD, SLD content, AHJ specifics. The point is to delete the hand-drafting hours between an engineered design and the deliverable, not the engineering.
Do I need to learn Python or AutoLISP to automate solar drafting?
No, though both work. Scripting gives you full control at the cost of building and maintaining the tools yourself — our tutorials teach exactly that path. A plugin like Branch ships the finished tools inside AutoCAD. Leaf Automation Studio is the third path: describe the drafting task in plain English and the Studio authors the tool; run it on Leaf or export it to AutoCAD. The authoring-and-export path is being built in the open, with the evidence published.
What does solar drafting automation cost?
Scripting costs engineering time instead of license fees. Branch is $299 per month per daily active user, averaged monthly, with no seat limits and a 14-day trial. Hosted runs on Leaf are metered per run. Vendors in adjacent categories meter differently — per-design credits, per-deliverable fees, project caps — which is why the comparison pages on this site quote each vendor's own published terms.
Comparing specific tools instead? The comparison pages quote each vendor's own published pricing and terms.
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