A harness enquiry that arrives as a photo of a sample and a quantity can be quoted, but the quote will carry assumptions, and every assumption is a risk to price, lead time and fit. An enquiry with a complete data pack is quoted faster and more tightly, and the first article is far more likely to be right. This checklist covers what to send.
Drawings
Send the harness drawing at its current revision, showing the layout, branch lengths and take-out positions with tolerances, and the connector views. If the harness is built on a formboard at full scale, say so. For rolling stock and locomotives, include the relevant schematic or wiring diagram reference.
Wire list
A from-to list gives every circuit: its number, wire type, size and colour, and the connector and cavity at each end. The wire list is what the continuity tester is programmed from, so errors in it pass straight into the product.
Bill of materials
| Item | What to specify |
|---|---|
| Wire | Standard and type (for example ISO 6722 class, FLRY-B, AVSS, GXL, or rail cable to ELRS or EN specification), size and colour |
| Terminals and connectors | Manufacturer and part number, plating, and whether an equivalent is acceptable |
| Seals and cavity plugs | Part numbers matched to wire insulation diameter |
| Protection | Conduit, sleeving, tape or overmould, with material and fire rating where required |
| Identification | Labels, ferrule markers, sleeves and their text |
Requirements
State the tests to be performed and recorded, the workmanship standard, and the applicable specifications. For railway coach and locomotive harnesses these are usually the EDTS and RDSO specifications named on the drawing; for rolling stock built to European practice, the EN 45545-2 hazard level. For vehicles, state any customer approvals required. Give annual volume, batch sizes and the call-off pattern, and the packaging and labelling needed at the receiving line.
What sets lead time
The longest item usually decides the date. For many harnesses that is a connector or terminal with a long factory lead time, particularly where the drawing names one manufacturer’s part with no approved equivalent. Crimp applicators for a new terminal family, a formboard for a new layout, and special wire that has to be produced to order also add time. First-article approval sits on the critical path for any new part number, so a prompt review by the customer shortens the overall programme. Flagging which components the customer will free-issue, and which the supplier should buy, removes a common source of delay.
APAR builds harnesses for automotive and EV platforms, railway coaches, locomotives and solar projects, from simple earthing leads to complex assemblies with multiple connectors, overmoulds and strain relief. Send the data pack through the enquiry form on any of those pages.