Cable Assembly Guidelines for Quoting

To obtain a quote for a custom cable assembly, manufacturers require detailed information in order to provide a firm cost and project timeline. Even just a budgetary quote response will require a sketch with preliminary design information. Since most development projects will yield several design iterations and prototypes along the way, it is important to understand what information is required to complete a quote and what information is not relevant for a custom build quotation. The most important piece of information is a 2-dimensional drawing. For example, this can be a sketch with dimensions or a completely detailed production drawing. To help understand the overall design objective, many cable manufacturers will request information such as the application, environmental requirements, the type of electrical signal being passed, and the overall program timeline.

The more information provided at the quote stage the better, allowing for a faster and more robust quote. At Epec, we can support your program whether you have a napkin sketch or a complete 3D model and drawing package. Our goal is to help understand your project so we can steer your design toward a low-cost, low-risk, and high-reliability solution.

At a minimum, the following information is required to launch your custom cable quote:

  • Wire AWG size and material
  • Wire length
  • Number of conductors
  • Connectors on each end
  • Required overmolding
  • Specialty components or processing

Below you will find a guideline of the critical design inputs that are needed to quote your custom cable assembly. If some of this information is not known or unavailable, Epec can help gather the required information to complete your quote.


Application

It's critical for manufacturers to understand the design application for your custom cable. What is your custom cable going to do? Where will it be used? Is this something you are already making and with design history on, or is this a brand-new application? Does this project carry an export control designation, or are their supply chain constraints that we must know? Sharing as much information about the application and design intent will allow our team to quickly quote and build your custom cable assembly.

  • What industry is this for?
  • Is this a new or existing design?
  • What is the design intent or what does the cable do?
  • What is your program timeline?
  • Are there qualification or test requirements?
  • What quantities are required for samples and production?
  • Will you consider locally sourced equivalent wire and components?
  • Is this export controlled?
  • Do you require any First Article Inspection data?

Conductor

The wire's center conductor is the internal copper core that transmits the electrical signal. The conductor design will drive flexibility, the amount of power, and can even dictate type of electrical signal.

  • The wire size
    • AWG (gauge)
    • CM (circular mils)
    • mm2
  • The type of stranding
    • Single/solid
    • Stranded
    • High strand count
  • Conductor coating
    • Bare copper
    • Tinned copper
    • Silver plated
    • Other

Drawing Information

The majority of cable assembly drawings already contain the required information to complete a quote, especially if its already in production. If a drawing is not available, there are several critical pieces of information that are required to complete a quote. Even a budgetary quote is not possible without most of this information.

  • Sketch or drawing of the desired design
  • Electrical Schematic
    • Pinouts need to be stated
  • Overall length
    • Location and length of breakouts
  • Tolerances
  • Critical dimensions
  • Testing requirements

Insulation/Jacket

The wire jacket, also known as insulation, is the plastic covering around the conductor that electrically insulates the cable. This can be both the internal insulation or the outside jacket seen by the user. Typically, red, black, green, or white, the insulation color is standardized but can also be customized for the application. The insulation and jacket material will also drive the temperature rating, flexibility, and overall resilience to the elements and chemicals.

  • UL style or AWM rating
  • Voltage and temperature rating
  • Jacket color
  • Outdoor/water exposure
  • Chemical resilience

Shielding

The shield layer on a cable is a conductive sheath of foil or braided wire around the outside of a jacketed wire. Shielding helps protect the internal electrical signal from outside interference and keeps all electronic emissions inside the cable. It's critical to understand the industry and application since this will drive certification requirements and the type EMI/EMC shielding necessary.

  • Braided shield layer
    • Tinned copper
    • Wire mesh and overbraid
  • Foil shield layer
    • Polyester foil shield
    • Metallized tapes
  • Connector shielding
    • Conductive housings
    • Foil layers within overmold

Connector

A cable's connector is a metal and plastic interconnect that allows the wire's internal copper conductor to be properly mated with the other parts of the assembly. Connectors range in cost and complexity, so it's best to properly match the application with your connector scheme. Some connector systems have lower cost "equivalent" or "sub" options, offering a form, fit, and function replacement.

  • Manufacturer's P/N
  • Connector type and gender
  • Orientation of the connector
  • Locking and polarization
  • Shielding
  • Overmolded strain relief

Overmolding

The overmolding on a cable assembly is typically used to ruggedize delicate components or provide an added level of customization. The overmold material is selected to address a specific design challenge and must be matched to the cable's jacket material. Overmolds can use existing house tooling for common connectors or customized tooling dedicated to the project. Epec can support both the overmold design and the fabrication of tooling.

  • Material requirements
    • PVC
    • TPE/TPU
    • Polypropylene
    • Others are available upon request
  • Color requirement
    • Color match a sample
    • PMS color
  • Dimensional Information
    • 3D model/.STP model
    • 2D drawing
    • Critical dimensions
  • Specialty requirements
    • Fungal resistance
    • Shielding

Environmental and Test Considerations

Many cable assembly projects require some type of testing in order to validate a design requirement. This can include submersion tests, pull and flex mechanical tests, or sophisticated electrical tests that require specialized instrumentation. Testing can be performed on 100% on units or can be performed on a subset of specimens.

  • Waterproofness and leak testing
    • IP rating
    • Mil-spec evaluation
    • Pressurization tests
  • Mechanical testing
    • Pull testing
    • Bend radius test
    • Cyclic bending
  • Electrical testing
    • Continuity and resistance
    • HIPOT
    • Insulation resistance
    • Insertion loss
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