Key Takeaways (Executive Summary)
- The Goal: A perfect drawing results in an accurate quote. Vague requirements lead to "No Bid" or expensive padding to cover unknown risks.
- The "Big 3" Specs: You must define Electrical (Voltage/Current), Mechanical (Length/Connectors), and Environmental (Temp/IP Rating) parameters explicitly.
- Tolerances: Loose tolerances save money. Standard cable length tolerance is usually +/- 1%. Demanding +/- 1mm on a 5-meter cable drives up cost unnecessarily.
- The Data Pack: A complete RFQ includes a 2D PDF drawing, a Bill of Materials (BOM), and a Pinout Table (Netlist).
- Garbage In, Garbage Out
In the contract manufacturing world, we have a saying: "If it isn't on the print, it doesn't exist."
We receive dozens of RFQs every week. Some are detailed engineering marvels; others are a photo of a napkin sketch. The difference determines whether your project launches on time or gets stuck in "Engineering Query" purgatory for weeks.
To help you get an accurate quote and a perfect prototype on the first try, we have compiled this Design Checklist. Before you hit send on your next cable project, run it through these 5 steps.
Step 1: Electrical Requirements (The "Inside")
Don't just list the connectors. You must define what is flowing through the wires.
- Voltage: Is this 12V DC or 480V AC? This determines the insulation thickness and UL rating.
- Current (Amps): What is the continuous load? This dictates the Wire Gauge (AWG). (Refer to our AWG Ampacity Chart).
- Signal Integrity: Are you running high-speed data (USB, Ethernet)? If so, you must specify Twisted Pairs and Shielding.
- Pinout (Netlist): A simple table showing "Pin 1 to Pin 1." Never assume a 1-to-1 mapping unless stated.
Step 2: Mechanical Constraints (The "Outside")
- Overall Length: Defined from connector face to connector face.
-
Tolerances: Standard industry tolerance is IPC Class 2.
- Cable < 1ft: +/- 0.5 inches
- Cable > 10ft: +/- 2 inches
- Tip: Only use tight tolerances where it physically matters (e.g., inside a tight enclosure).
- OD (Outer Diameter) Limit: Does this cable need to fit through a specific grommet or hole size? State the "Max OD" allowed.
- Flexibility: Will this cable move? (See our High Flex guide). If yes, specify the minimum bend radius.
Step 3: Environmental Specs (The "Survival")
Where will this cable live?
Comparison Table: Selecting the Right Protection
Match your environment to the required specs.
|
Environment |
Key Threat |
Recommended Spec / Material |
|---|---|---|
|
Office / Home |
Mild |
PVC Jacket (Standard UL 1007) |
|
Factory Floor |
Oil, Impact, Traffic |
PUR Jacket, IP67 Connectors |
|
Outdoor |
UV Sun, Rain, Cold |
Carbon Black UV Stabilized, IP68 |
|
Automotive |
Heat, Vibration, Fluids |
XLPE Wire (TXL/GXL), 125°C rating |
|
Medical |
Sterilization |
Silicone, USP Class VI, Autoclave safe |
Step 4: The Components (The BOM)
- Connectors: List the Manufacturer and Part Number (e.g., Molex 39-01-2040).
- Contacts: Don't forget the terminals! They are sold separately.
- Alternates: Add the phrase "Or Equivalent Approved" if you want to lower costs. This allows us to use compatible generic connectors if the brand name is out of stock.
Step 5: Compliance and Testing
- RoHS / REACH: Mandatory for almost all global markets.
- UL Labeling: Do you need a UL sticker on the cable? This requires a certified UL wiring harness shop (like us).
-
Testing:
- Standard: Continuity (Open/Short).
- Advanced: Hipot (High Voltage), Pull Force, VSWR (RF).
The "Perfect Data Pack" Example
When you submit your RFQ, your email should contain:
- PDF Drawing: Visual representation with dimensions.
- Excel BOM: Part numbers and quantities.
- Excel Pinout: From/To list.
- CAD Files (Optional): STEP files help us design custom molds, but the PDF is the master legal document.
Frequently Asked Questions (FAQ)
Q: Can you build a cable from a sample? A: Yes, this is called Reverse Engineering. You send us the physical cable, and we measure it, identify the connectors, and create the drawing for you. (Note: There is usually a small NRE fee for the drawing creation).
Q: What is a "First Article" (FAI)? A: Before we build 1,000 cables, we build one. We measure every dimension and record it in a First Article Inspection report. You review this sample and report. Once you say "Approved," we start mass production.
Q: Do I need to specify the wire colors? A: Yes! If you don't, we will pick standard colors (Red/Black) or whatever is in stock. If you need a specific color code (e.g., DIN 47100 for sensors), list it in the Pinout table.
About the Author
Michael Wang
Senior Technical Engineer
As the technical lead at TeleWire, Michael bridges the critical gap between complex engineering requirements and precision manufacturing. With deep expertise in Design for Manufacturing (DFM) and signal integrity, he oversees the technical validation of custom interconnect solutions for mission-critical automotive, industrial, and medical applications.
