The Short Answer: What a Complete Wire Harness RFQ Contains
A complete wire harness RFQ gives the supplier everything needed to price and build without guessing: a released drawing with its revision, a bill of materials with manufacturer part numbers, the wire and connector details, the test and acceptance criteria, the operating environment, quantities and delivery, and any supplier requirements. Each item you leave out forces an assumption, and assumptions are either priced in as risk or discovered later as a requote.
This checklist lists the 15 details, grouped into four parts, and says why each one changes the quote. Use it as a pre-submission check. A printable version is in our wire harness factory requirements checklist.
Why the BOM alone is a lot to specify
A typical wire harness BOM can contain 50 to 100 different items, according to this industry analysis, and each unspecified item is a place where the supplier has to make an assumption. (Source: Cadonix, RFQ challenges in the wire harness industry)
Whether you are sourcing custom cable assemblies, connector-specific harnesses, automotive harnesses or industrial wire harnesses, the same 15 items apply.
Part 1: Drawing, Materials and Test (Items 1 to 6)
These six items define what is being built and how it is checked. They are the foundation of the quote, and they are also the ones most often incomplete.
| # | Item | What to include | Why it changes the quote |
|---|---|---|---|
| 1 | Released drawing and revision | Assembly drawing (PDF plus native CAD if you have it), current revision letter, and the revision history if it changed recently. | The supplier prices what is drawn. An unclear revision means quoting, or building, the wrong version. See drawing revision control. |
| 2 | Bill of materials with manufacturer part numbers | Wire, connectors, terminals, seals, sleeving and labels, each with manufacturer and part number, not just a description. | Connectors and terminals set most of the cost and lead time. A generic description forces the supplier to guess a part or ask. |
| 3 | Wire specification | Gauge (AWG or mm²), insulation type and voltage rating, stranding, color or color code, and length with tolerance for each circuit. | Insulation and stranding change material cost and crimp tooling. Length tolerance affects cutting and fit. See AWG ampacity and size chart. |
| 4 | Connectors, terminals, seals and pinout | Housing and terminal part numbers, seals and plugs, cavity-to-wire pinout, and any keying or coding. | A wrong terminal-to-wire match is a reliability risk, and sealed connectors need the right seal and wire OD. A wire list or pinout table removes ambiguity. |
| 5 | Shielding, twisting, protection and marking | Shield type and termination, twisted pairs, sleeve, tape or conduit, overmold, label content and placement. | Each option adds a process step and material. Leaving it off the drawing means the first quote may not include it. |
| 6 | Test and acceptance criteria | Workmanship standard and class (for example IPC/WHMA-A-620), electrical tests (continuity, hipot if required), pull test and sampling rules. | Test time and fixtures are part of the price. Class 3 versus Class 2 changes inspection effort. See the IPC-620 inspection guide and quality testing methods. |
Part 2: Operating Environment (Items 7 to 9)
Environment decides material and sealing. Describe where the harness actually lives, not only the nominal conditions.
| # | Item | What to include | Why it changes the quote |
|---|---|---|---|
| 7 | Temperature range | Minimum and maximum ambient, plus any hot spots near the harness. | Sets insulation and sleeving material; higher-rated materials cost more and may be longer lead. |
| 8 | Ingress, fluids and UV | Required IP rating, exposure to oil, fuel, coolant or chemicals, and sunlight. | Determines sealed connectors, overmolding and jacket material. |
| 9 | Mechanical loads | Vibration, flexing or torsion, bend radius, routing constraints and strain relief. | A harness that flexes needs different cable construction than a fixed one, and strain relief is often missing from first-draft drawings. |
Part 3: Commercial Terms (Items 10 to 13)
Commercial details change unit price and how the supplier plans material and production.
| # | Item | What to include | Why it changes the quote |
|---|---|---|---|
| 10 | Quantity tiers and annual usage | The immediate order size, plus expected annual usage and the quantity breaks you want priced. | Volume drives material pricing and how setup is spread across units. Tiers let the supplier price accurately. |
| 11 | Delivery date and ship-to | Required delivery date, ship-to location, and whether delivery is one lot or scheduled releases. | Short dates can force expedited material. Scheduled releases change how stock is held. See the lead time guide. |
| 12 | Packaging, labeling and traceability | Packaging method, labeling format, lot or serial traceability and the records you want back. | Labeling and traceability add handling and documentation time. |
| 13 | Compliance requirements | RoHS or REACH, UL recognition or listing, and any customer specification or industry standard. | Compliance limits the parts and materials the supplier can use. |
Part 4: Supplier Requirements (Items 14 and 15)
State what you expect from the supplier up front so you receive quotes you can compare.
| # | Item | What to include | Why it changes the quote |
|---|---|---|---|
| 14 | Approved alternates and change control | Acceptable alternates for long-lead or allocated parts, and your rule for changes (written approval for any substitution). | Pre-approved alternates avoid a stop while waiting for approval. See the connector shortage RFQ guide. |
| 15 | Quality documents you want | First-article report, certificate of conformance, test records, and any supplier audit or qualification requirement. | Documentation is part of the work and the cost, and it is cheaper to define before the build than to request afterwards. |
Five Common RFQ Gaps and What They Cost
These gaps are the ones that most often turn a one-round quote into a back-and-forth. The cost of each is described qualitatively, because it depends on the program.
| Gap | What happens | How to avoid it |
|---|---|---|
| Missing or unclear drawing revision | The quote may be for an older version, and a requote follows when the revision is clarified | Put the revision letter on the drawing, the BOM and the RFQ cover note |
| BOM without manufacturer part numbers | The supplier picks an equivalent or asks, which adds a clarification round and can change cost and lead time | List manufacturer and part number for every connector, terminal and seal |
| No test or acceptance criteria | Test effort is guessed; the first quote may omit fixtures or hipot | State the workmanship class and the electrical tests required |
| Only the order size, no annual usage | The supplier cannot price volume tiers or plan material | Give the order size and the expected annual usage |
| Environment and strain relief left off | Materials are underspecified, which shows up as underquoting or field failures | Describe temperature, fluids, vibration or flex, and strain relief on the drawing |
The One-Page Checklist
Tick each box before you send the RFQ. If an item does not apply, write “not applicable” rather than leaving it blank, so the supplier knows it was considered.
Drawing and materials
- ☐Released drawing with revision
- ☐BOM with manufacturer part numbers
- ☐Wire gauge, insulation, color and length with tolerance
- ☐Connector, terminal and seal part numbers and pinout
- ☐Shielding, sleeving, overmold and labels
- ☐Workmanship class and tests
Environment
- ☐Temperature range
- ☐IP rating, fluids and UV
- ☐Vibration, flex and strain relief
Commercial
- ☐Order size and annual usage
- ☐Delivery date and ship-to
- ☐Packaging, labeling and traceability
- ☐Compliance (RoHS, REACH, UL, customer specs)
Supplier requirements
- ☐Approved alternates and change control
- ☐Quality documents (first article, CoC, test records)
How to Package and Send the RFQ
Send the documents together so the supplier can open one package and quote: the drawing as a PDF (and native CAD if you have it), the BOM as a spreadsheet, and the wire list or pinout as a table or CSV. Put the drawing revision and the quantities in the cover note. If the harness is to be built to a design guide you follow, mention it; our wire harness design guide covers the design side, and the custom wire harness cost guide explains what moves the price once the RFQ is complete.
If your connectors have long lead times or are allocated, flag that in the RFQ and list approved alternates, as described in the connector shortage RFQ guide. For marine and similar programs with weekly delivery needs, see the marine harness RFQ and buffer stock guide.
Next Steps: Submit a Complete RFQ
A complete RFQ is the foundation of a smooth harness project: quotes are easier to compare, the first quote is closer to the final price, and fewer assumptions are carried into production. Our work follows IPC/WHMA-A-620 workmanship; see the capabilities page for current certificate information and what each facility holds. To send a drawing and BOM for engineering review, contact the engineering team.
Related Resources
Cable Assembly vs Wire Harness - understanding the differences
Wire Harness Design Guide - critical steps for engineers
Wire Harness Lead Time Guide - what drives delivery time
Manufacturing Capabilities - equipment and certifications
Frequently Asked Questions
What should a wire harness RFQ include?
A complete RFQ provides the assembly drawing with its revision, the bill of materials with manufacturer part numbers, the wire list and connector pinout, quantities and expected annual usage, the operating environment, test and acceptance criteria, and packaging and delivery expectations. The more complete it is, the faster and more accurate the quote.
Why do incomplete RFQs cause delays?
Missing specifications force the manufacturer into clarification cycles and often a requote once the gaps are filled. Each round adds time and increases the risk of building to the wrong assumption.
What is the most commonly overlooked RFQ detail?
Strain relief, test requirements and the operating environment are frequently left off. They directly affect material choice and reliability, so omitting them leads to underquoting or field failures.
Should I specify approved alternate components?
Yes. Listing acceptable alternates for long-lead or allocated parts lets the manufacturer source without waiting for a fresh approval, and the alternates should be covered by your change-control rule.
How does quantity affect the quote?
Quantity drives unit pricing through material pricing and how setup and tooling are spread across units. Share both the immediate order size and the expected annual usage so the supplier can price tiers accurately.
What lead-time information should I provide in an RFQ?
State your required delivery date, the ship-to location, whether delivery is one lot or scheduled releases, and your annual usage, so the supplier can plan procurement and, if needed, recommend buffer stock for long-lead components.
What file formats should I send with a wire harness RFQ?
A PDF of the assembly drawing (plus native CAD if you have it), the BOM as a spreadsheet, and the wire list or pinout as a table or CSV. State the drawing revision in the cover note so everyone is quoting the same version.
Can I get a budgetary quote with less information?
Often yes, but it will carry assumptions and is not a firm price. The supplier can usually give a rough range from a drawing and quantities, then firm it up once the BOM part numbers, test requirements and environment are confirmed.
