The permit set for a Waterbury rooftop was approved in September. The system was installed in October. In between, the inverter on the set went on backorder, the crew installed a different model, and a string was moved to a second roof plane because of a vent stack nobody had surveyed. The building inspector passed it. Now the utility wants to know what is actually on the house. That is the job of Waterbury solar as-built drawings.
An as-built is not a new design. It is a record of what was installed, drawn clearly enough that the utility, the town, and the next electrician can trust it. In Connecticut it is often the last drawing between a finished system and permission to operate.
When Waterbury solar as-built drawings are needed
Waterbury is in Eversource's Connecticut territory. Residential systems connect under the Residential Renewable Energy Solutions program, and the utility compares what was installed with what was approved in the interconnection application. When those match, the as-built can be the approved set marked "as built" with no changes. When they do not, the drawings have to change.
Field changes that require a revised one-line or plan:
- Inverter or microinverter model change. Even with the same AC rating, the model, listing, and data sheet change.
- Module count or model change. DC size, string configuration, and possibly the AC size move with it.
- String or array layout change. A string moved to another roof plane changes the roof plan and the conductor path.
- Point of connection change. A load-side breaker that became a supply-side tap, or a panel that was replaced.
- Rapid shutdown device change. The equipment and the labels both change.
- Conduit route change. The route, length, and conductor sizing on the schedule.
Our post on Connecticut solar PTO covers the steps after inspection. The Eversource Connecticut interconnection post covers the application those as-builts are compared against.
What a usable as-built looks like
Athol Energy prepares as-built drawings from field information supplied by the installer. We were not on the roof. That is why the field package matters. To draw an accurate as-built we need:
- Photos of every label: modules, inverter or microinverters, disconnect, main panel, meter, and rapid shutdown devices.
- A marked-up roof plan showing what was actually installed, string by string.
- The inspection result and any corrections the inspector required.
- Conduit route with approximate lengths and where it entered the building.
The revised one-line should show the installed equipment, the actual DC and AC sizes, and the point of connection as built. The roof plan should show the actual array. The title block should say "As-Built," with the date and a short revision note that lists what changed. A reviewer should not have to compare two PDFs to find the difference.
Keep the record matched to the utility file
The most common delay is not a bad drawing. It is an as-built that changes the AC size without anyone telling the utility. If the installed inverters change the AC rating, the interconnection application may need an update before PTO. Check that before the as-built is submitted. The as-built drawings after inspection post covers the most common bouncebacks.
The code edition stays the one the permit was issued under. Connecticut's 2022 State Building Code adopts the 2020 NEC with amendments. An as-built for a Waterbury job does not switch to another state's edition just because the drafter's last job was in Massachusetts.
The homeowner should get a copy
An as-built is also a homeowner document. It is what the next roofer, electrician, or buyer's inspector will ask for. Give the customer a PDF with the final one-line, the roof plan, and the equipment list. If they ever add a battery, an EV charger, or a plug-in device under Connecticut's new law, the next designer starts from the right drawing. Our post on Connecticut plug-in solar explains why noting every source on the premises matters.
Questions about as-built drawings in Connecticut
When does a Connecticut solar job need as-built drawings?
When the installed system differs from the approved set, for example a different inverter, module count, string layout, or point of connection. If nothing changed, the approved set can usually be marked as built.
Does an inverter swap with the same AC rating need an as-built?
Yes. The model, listing, and data sheet change even if the rating does not. The one-line and equipment schedule should show the installed model.
What do I need to send for an as-built?
Label photos of all equipment, a marked-up roof plan of the installed array, the inspection result, and the conduit route.
If you have Waterbury or Naugatuck Valley jobs waiting on PTO because of field changes, send the photos and markups. Connecticut solar design from Athol Energy will turn them into a clean as-built set. Contact us.