Quick answer
An itemized record of a solar system’s specified components and materials, with units and quantities for procurement and installation planning. Scope, prices and completeness require review.
What Is a Solar Bill of Materials?
Answer: A solar bill of materials, or BOM, is an itemized record of the components and materials specified for a system. It supports purchasing, delivery checks and installation planning by identifying parts, units and quantities. Prices and supplier details can be added for procurement. A BOM needs a defined design revision and scope; a generated list is not proof that every required item is included.
Autodesk’s BOM documentation distinguishes the CAD structure from an engineering BOM that can also contain additional purchased items. This matters in solar: items absent from the model may still need to be supplied.
A bill of quantities focuses on described and measured work for tendering or cost control. A BOM focuses on the selected parts to procure and stage. The documents can overlap, but a priced materials list alone does not establish the entire installed project cost.
What to Include in a Solar BOM
Use categories appropriate to the actual system. Do not assume every project uses optimizers, combiner boxes, a particular conductor size or a ground rod simply because a template lists them.
| Category | Examples to review | Quantity or specification source |
|---|---|---|
| Modules | Exact manufacturer, model and quantity | Released array layout and equipment selection |
| Power conversion | Inverters, applicable module-level equipment and accessories | Compatible system configuration and exact product instructions |
| Racking and attachments | Rails, clamps, splices, attachment and flashing components | Site-specific racking design and manufacturer requirements |
| DC circuits | Conductors, compatible connectors and applicable protection | Electrical design, actual routes and termination requirements |
| AC circuits | Conductors, conduit, fittings, disconnects and protection | Connection design, routes and equipment requirements |
| Grounding and bonding | Specified conductors, connectors and bonding components | Applicable design and equipment instructions |
| Monitoring | Required communication, monitoring and metering equipment | Selected architecture and supported configuration |
| Labels and consumables | Required signs and specified installation materials | Applicable installation requirements and documented site scope |
For each line, record a stable item identifier, description, manufacturer/part number where applicable, unit, quantity and source revision. A purchasing view can add supplier SKU, unit price, currency, quote date, validity, availability and lead time. Mark estimated or unresolved entries visibly.
Views for Different Project Stages
Engineering view: organize selected components by system function and preserve the design reference. A missing part in a drawing does not mean it is unnecessary.
Procurement view: group items for vendors and purchasing. Distinguish the manufacturer part number from the distributor’s SKU, pack size and order unit. Confirm substitutions through the responsible design review before ordering.
Installation view: create delivery and staging lists suited to the site and installation sequence. Check received materials before mobilization rather than discovering shortages during work.
Installed record: reconcile accepted field substitutions, actual equipment identifiers and material changes at handoff. Connect the record to as-built drawings. Specific warranty, inspection and handoff requirements depend on the product, agreement and authority.
These are practical views of the same project information, not a mandatory worldwide BOM classification.
Quantity Review Before Purchasing
- Modules: reconcile layout count with the selected model. Capacity arithmetic does not determine rail, attachment or protection quantities.
- Racking: use the actual roof type, module arrangement and engineered attachment/rail configuration. Panel count alone cannot establish clamp or splice counts.
- Wire and conduit: distinguish measured route length from conductor length. Multiple conductors in one route, vertical drops, terminations and approved allowances can change purchasing quantities.
- Accessories: review compatible connectors, fittings, monitoring and labels against the selected system and instructions.
- Ordering units: account for packs, stock lengths and available inventory. Separate installation quantity, purchased quantity, approved spares and waste allowances.
Do not use a universal 5–10% waste factor as a substitute for review. Record the reason and basis for an allowance, then compare it with actual use and returns.
A Checked Cost-Variance Example
Suppose a hypothetical BOM estimates $14,200 of materials, and comparable actual material expenditure is $14,850:
Actual minus estimated cost = $14,850 − $14,200 = $650.
Cost variance = $650 / $14,200 × 100 = 4.58% over estimate.
Actual-to-estimated cost ratio = $14,850 / $14,200 × 100 = 104.58%.
That ratio is not a general “BOM accuracy score.” A cost increase can result from quantity changes, price changes, freight or a changed scope. It does not prove missing hardware or lost profit. Compare the same scope and cost basis, then separate quantity and price differences. For another illustrative scale check, 5% of a $15,000 material budget is $750, without implying any observed margin outcome.
What Automation Can Support
Auto BOM generation can help organize supported design quantities. Verify which items come from geometry, a component library, user inputs or assumptions, and identify items excluded from the export.
As a vendor-specific example, IronRidge’s Design Assistant page describes project editing, distributor ordering and access to permit-pack services from its BOM page. This does not establish that any tool produces every electrical, structural and field-dependent quantity or that a BOM guarantees permit acceptance.
When changing equipment or layout, review affected quantities and compatibility rather than assuming every dependency updates correctly. Version the list and identify approval for purchasing separately from draft design status.
Designers own quantity sources and unresolved scope. Procurement and installation teams reconcile receipts, shortages, approved substitutions and leftovers. Sales teams should use dated supplier quotes and make exclusions clear; listing premium equipment does not establish performance or price superiority.
Book a SurgePV demo with a sample project to evaluate the actual export fields, supported quantities and review workflow you need.
Frequently Asked Questions
What is included in a solar BOM?
The components and materials within its defined system scope, with descriptions, units and quantities. Procurement details can include part numbers, supplier references and dated prices. Completeness requires review against the actual design and site requirements.
Does a BOM include labor?
A solar procurement BOM primarily tracks components and materials. Labor and installation costs are usually handled in related estimating or work-pricing records. Document conventions vary, so state the scope explicitly rather than relying on the acronym.
Can a panel layout generate a complete installation BOM?
A layout may support module counts and some modeled quantities. Routes, equipment configuration, structural design, accessories and field conditions require their own inputs and checks. Confirm what the tool includes and excludes.
Related Glossary Terms
About the Contributors
Solar-industry contributor
Nimesh Katariya contributes to SurgePV content concerning solar project workflows. This profile intentionally does not assert certifications, project totals, seminar counts, or technical-review authority without retained verification evidence.
Editorial contributor · SurgePV
Rainer Neumann is credited as an editorial contributor on SurgePV content. This profile does not assert engineering credentials, project totals, software-testing experience, education, speaking engagements, or media citations because independent verification evidence is not retained in the publication record.
