Prototype Cable Assembly Checklist for NPI

Prototype cable assemblies allow engineers to evaluate electrical, mechanical, routing, connector, and manufacturing requirements before a product transitions into repeat production.

A useful prototype is not simply a small production order. It should help identify incomplete documentation, fit issues, component concerns, testing requirements, and manufacturing questions while changes are still easier to make.

Use the following checklist when preparing a prototype cable assembly or wire harness project.

1. Prepare the Latest Drawing

The drawing should identify applicable requirements such as:

Cable length
Branch lengths
Connector locations
Mechanical dimensions
Tolerances
Labels
Cable exit direction
Revision

Make sure the manufacturer knows which drawing revision is current.

2. Provide a Detailed BOM

The BOM should identify available information such as:

Connector manufacturer
Connector part number
Terminals or contacts
Wire manufacturer or specification
Cable specification
Heat-shrink
Sleeving
Labels
Other customer-approved components

Manufacturer part numbers are especially useful for avoiding ambiguity.

3. Confirm the Pinout and Wiring

For electrical connections, provide:

Pin-to-pin wiring
Wire colors
Wire gauges
Signal identification
Ground connections
Shield termination
Splices when applicable

Any differences between the drawing, BOM, and pinout should be resolved before the prototype is built.

4. Define Mechanical Constraints

Prototype evaluation should consider how the cable actually fits into the equipment.

Provide information about:

Routing space
Bend radius
Connector orientation
Cable exit direction
Enclosure dimensions
Moving components
Strain near connectors
Installation sequence

Mechanical information can prevent a cable that works electrically but does not fit the finished product.

5. Define Electrical and Environmental Requirements

Depending on the application, specify:

Voltage
Current
Signal type
Data requirements
Shielding
Grounding
Temperature
Flex or movement
Vibration
Moisture
Chemical exposure

Requirements should reflect the actual product application.

6. Identify Long-Lead Components Early

Prototype schedules can be affected by:

Connector availability
Custom cable
Specialty terminals
Minimum order quantities
Obsolete components
Long supplier lead times

If a potential alternate component is identified, it should be reviewed and approved through the customer's change process before use.

7. Define Prototype Testing

Testing depends on the product.

Requirements may include:

Pinout verification
Continuity
Miswire detection
Dimensional inspection
Pull-force testing when specified
Insulation resistance when specified
Hi-Pot when specified
Functional testing when specified

Do not assume every prototype requires exactly the same testing.

8. Define First Article Requirements

Some programs require formal first-article documentation, while others require only prototype evaluation.

Before ordering, confirm:

Required inspection documentation
Critical dimensions
Component verification
Test results
Customer approval requirements

First-article requirements should be defined by the individual program.

9. Plan for Production Early

Even during prototype development, consider:

Expected production quantity
Annual forecast
Production location requirements
Material lead times
Required tooling
Test fixtures
Packaging
Revision control

A design that works for a few engineering samples may still require additional planning before repeat production.

Prototype vs. Released Production

Prototype builds are typically used when design or manufacturing requirements are still being evaluated.

Released production should rely on controlled documentation including:

Approved drawings
BOM
Pinout
Current revision
Work instructions
Inspection criteria
Testing requirements

For released products, visit Build-to-Print Cable Assembly Services.

What to Send for a Prototype Quote

Send:

Drawing
BOM
Pinout
Connector information
Cable specifications
Mechanical requirements
Prototype quantity
Testing requirements
Current revision
Target schedule

For prototype and NPI manufacturing support, visit Quick-Turn Cable Assembly Prototyping.

Request a Prototype Cable Quote