Business
Outsourcing solar design: what to send so the set comes back right
Short answer
Send the address, the equipment list with exact model numbers, the main service panel rating and its location, the racking system, and photographs of the service panel label, the roof, and the attic framing. Most back-and-forth on an outsourced set comes from a missing panel photograph or a model number given as a family name rather than a part number.
The information
- Site address. Determines the jurisdiction, the adopted codes, and the wind and snow criteria.
- Module make, model and quantity. The exact part number, not the series. Wattage varies within a family.
- Inverter or microinverter make and model. Same rule. Output current drives the busbar arithmetic.
- Main service panel rating and location. Both. The rating drives the interconnection method; the location drives conduit routing and disconnect placement.
- Racking system. Attachment spacing and allowable spans come from the manufacturer's tables.
- Battery and EV charger, if any. Each adds requirements and a sheet.
The photographs
These are what actually prevent a round trip:
- The service panel with the label legible. Busbar rating, main breaker size and available spaces, all readable. This single photograph resolves more questions than any other.
- The meter and its surroundings. For disconnect placement.
- The roof, wide. Planes, obstructions, vents, existing conditions.
- The attic. Rafter size, spacing and whether it is truss or stick framing. A tape measure in the shot is worth a paragraph of description.
- Anything unusual. A problem corner, odd framing, a previous array.
What slows a set down
| What is sent | What it costs |
|---|---|
| Model given as a series name | A query, because wattage is ambiguous |
| Panel photograph unreadable | A query, because the busbar rating is the whole interconnection question |
| Panel location not stated | Conduit routing and disconnect placement guessed |
| No attic photograph | Attachment detail cannot be drawn to the actual framing |
| Roof covering unstated | Wrong attachment detail, and possibly a missed structural stamp |
A note on scope
Systems under 20 kW are quoted flat. Above that, system details drive the price, so send the specifics and ask. Contractors sending work on a standing weekly schedule are on a reduced rate — worth setting up if solar design is a regular line in your business rather than an occasional one.