Welcome to MiniProto's comprehensive guide to wire harness manufacturing. This documentation covers everything from basic concepts to advanced manufacturing processes, helping you understand how custom wire harnesses are designed, specified, and produced. Whether you're new to wire harnesses or looking to refine your specifications, this guide will walk you through the complete process from initial design communication through final quality assurance.

A wire harness is an organized assembly of insulated conductors bundled into a single, manageable unit. Each conductor keeps its own insulation, but the wires are grouped together for routing, protection, and ease of installation. Harnesses carry power, signals, and data while protecting against vibration, moisture, and abrasion through ties, sleeving, heat-shrink tubing, and jackets. They simplify wiring in complex systems by arranging wires and connectors into a defined, repeatable layout. *Suggested image: side-by-side photo of a loose bundle of wires vs. a finished harness.*

Both cable assemblies and wire harnesses manage multiple conductors, but their construction differs: - **Cable assembly**: conductors, shielding, and fillers are encapsulated in a common factory-applied jacket. - **Wire harness**: individually insulated wires are routed separately, then bound with ties, sleeving, or tubing. In short: cable assemblies are integral, pre-jacketed products; harnesses are flexible assemblies built from discrete wires. *Suggested image: diagram comparing a pre-jacketed cable assembly to a sleeved wire harness.*

MiniProto supports three main ways to share your design: 1. **Config Tool**: A step-by-step web tool for defining connectors, wires, lengths, labels, and sleeving. Best for prototypes and small runs when CAD is not available. 2. **Drawings**: Traditional PDF or CAD drawings remain standard for complex harnesses. Include schematics, lengths, gauges, and tolerances. 3. **Standards**: Referencing IPC/WHMA-A-620 (and specifying class 1, 2, or 3) ensures alignment on workmanship and inspection criteria.

The Config Tool is designed as a structured alternative to drafting and is best suited for basic harness designs. - **Add connectors/terminations**: Place connectors (or bare wire ends) on either side of the design canvas. These cover all termination types currently supported. - **Draw wires between ends**: Define each conductor by connecting one termination to another. Assign wire gauge, color, and length. - **Insert mid-elements**: Add splices or heat-shrink points directly into a wire path. - **Review & submit**: The tool automatically applies default tolerances, generates a schematic, and prepares a bill of materials for review. ⚠️ *Note: Multi-conductor cables are not yet supported in the Config Tool. It is intended for straightforward harnesses but is being continuously improved to handle more complex designs.* *Suggested image: screenshot of the Config Tool showing connector placement, wire drawing, and a splice element.*

To save time, MiniProto offers a library of **preconfigured harness types** built around the most common connector families and termination styles. For each preconfigured option, you can adjust: - Connector pin / wire count - Connector gender - Wire color - Wire length - Order quantity The connector families and termination styles themselves are fixed, which ensures parts are always in stock and lead times remain short. **Examples include:** - JST (PH, XH, VH series) - Molex (PicoBlade, Mini-Fit, KK) - Deutsch (DT and DTM series) **Benefits:** - Faster quoting and turnaround - Lower MOQs by standardizing around stocked connectors - No need to fully define a harness from scratch *Suggested image: thumbnail gallery of 3–4 preconfigured harness types (e.g., JST to JST, Molex to Molex, Deutsch to wire).*

### If you submit a drawing - **Quoting & engineering review** – Your drawing is reviewed for manufacturability and sourcing. Substitutions or design changes, if required, are noted in the quote email. The quote also confirms lead times and pricing (with quantity discounts when requested). - If the quote is not approved, adjustments can be made and a revised quote issued. This review–quote cycle continues until the design is finalized. - **Order confirmation** – Once you confirm acceptance of the quote by email, you'll receive a Stripe invoice. Production begins after payment is received. ### If you use the Config Tool - **Preliminary pricing** – You receive an instant price estimate and can place and pay for an order immediately. - **Engineering & sourcing review** – Our engineers verify manufacturability and material availability. Substitutions or adjustments, if needed, are communicated before production begins. If a design proves unmanufacturable, you will be fully reimbursed. ### Production Process (applies to both methods) 1. **Sourcing** – Components not held in stock are sourced at this stage. Lead times may be affected by supplier availability. 2. **Manufacturing** – Wires are cut and stripped, connectors crimped or soldered, conductors bundled, sleeved, and finished. 3. **Testing & inspection** – Visual and electrical checks ensure conformity, continuity, and proper dimensions. 4. **Packaging & shipping** – Harnesses are coiled or spooled, labeled, and shipped with tracking provided. *Suggested image: simple flow diagram showing Drawing path to Config Tool path to Production Process (Sourcing to Manufacturing to Testing to Shipping).*

MiniProto has developed specific recommendations based on years of wire harness manufacturing experience. These guidelines help ensure optimal cost, lead time, and quality for your custom harness projects. Our recommendations cover preferred components, quotation requirements, and strategies for reducing both cost and lead time while maintaining high manufacturing standards.

MiniProto maintains an extensive inventory of high-quality components from leading manufacturers. Using our preferred components ensures faster turnaround times, competitive pricing, and proven reliability. Our component selection is based on manufacturability, availability, and long-term support from trusted suppliers.

There are several ways to reduce the cost of a harness without compromising performance: - **Use our stocked components.** Choosing wire types, connectors and sleeving that we already carry avoids special‑order fees and minimum buy quantities. - **Minimize part count.** Combine conductors into multi‑core cables, reduce the number of distinct connector and conductor types, and eliminate unnecessary splices where possible. - **Relax tolerances.** Specifying standard tolerances instead of high‑precision options avoids extra setup and measurement steps and can lower cost by 15–40% (see the tolerance table in the Process & Quality section). Tolerances for wire harnesses rarely need to be designed to tight tolerances as slack can be easily dealt with when designing systems. - **Design for automated assembly.** Avoid extremely short branch lengths, choose common connectors, and allow enough stripped length for tooling. Automated cutting and crimping reduce labor cost. - **Order higher quantities.** Larger runs benefit from economies of scale on material and setup. We will work with you to establish scheduled deliveries and first article checks to decrease risk and minimize costs.

Lead time depends on part availability, production scheduling and shipping. To get your harness faster: - **Choose in‑stock wires and connectors.** Our standard UL1061, UL1007, silicone and GXL wires and common terminals are always on hand, whereas special colours or exotic connectors must be ordered. - **Provide complete information up front.** Clear drawings, accurate lengths and part numbers minimise back‑and‑forth and prevent delays during engineering review and manufacturing. - **Use off the shelf products.** Bypass the design phase and allow us to start cutting wire immediately. - **Allow standard tolerances.** Avoid specifying ultra‑tight tolerances unless truly necessary; standard tolerances allow us to use automated equipment and reduce rework. - **Plan ahead.** If you have a deadline, communicate it early and consider expedited processing or air freight.

Understanding the fundamental components of a wire harness is essential for effective design and specification. Each component serves a specific purpose in the overall assembly, from conducting electrical signals to providing mechanical protection. This section covers the key materials and components that make up a professional wire harness assembly.

Conductors are the electrical pathways in a wire harness, responsible for carrying power and signals. They come in two main forms: individual wires and multi-conductor cables.

We support most commonly available wire types, though only consistently stock a few varieties in order to minimize lead times. Users may request additional wire types in design notes, though additional fees may apply to account for shipping and supplier minimum order quantities. We highly encourage designing components to use our standard wire types when possible. Our standard wire types and colors are described in detail below.

The following table shows which wire colors are available for each of our standard wire types: | Spec | BK | BU | BN | GD | GN | GY | OG | PK | RD | SR | TQ | VT | WH | YE | | :---- | :---: | :---: | :---: | ----- | :---: | :---: | :---: | :---: | :---: | ----- | ----- | :---: | :---: | :---: | | UL1061 | ✔️ | ✔️ | ✔️ | ❌ | ✔️ | ✔️ | ✔️ | ❌ | ✔️ | ❌ | ❌ | ✔️ | ✔️ | ✔️ | | UL1007 | ✔️ | ✔️ | ✔️ | ❌ | ✔️ | ✔️ | ✔️ | ❌ | ✔️ | ❌ | ❌ | ✔️ | ✔️ | ✔️ | | UL1429 | ✔️ | ✔️ | ✔️ | ❌ | ✔️ | ✔️ | ✔️ | ❌ | ✔️ | ❌ | ❌ | ✔️ | ✔️ | ✔️ | | Silicone | ✔️ | ✔️ | ✔️ | ❌ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ❌ | ❌ | ✔️ | ✔️ | ✔️ | | GXL | ✔️ | ✔️ | ❌ | ❌ | ✔️ | ✔️ | ✔️ | ❌ | ✔️ | ❌ | ❌ | ✔️ | ✔️ | ✔️ |

Overview comparison of our standard wire types: | Spec | Type | Material | Gauge Range | Insulation | Voltage Rating | Temperature Rating | Supplier | | :---- | :---- | :---- | :---- | :---- | :---- | :---- | :---- | | UL1061 | Stranded | Tinned Copper | 28AWG - 16AWG | Semi-Rigid PVC | 300V | 80°C (176°F) | Remington Industries | | UL1007 | Stranded | Tinned Copper | 28AWG - 14AWG | PVC | 300V | 105°C (221°F) | Remington Industries | | UL1429 | Stranded | Tinned Copper | 28AWG - 16AWG | Irradiated XL-PVC | 150V | 105°C (221°F) | Remington Industries | | Silicone | Stranded | Tinned Copper | 30AWG - 6AWG | Silicone | 600V | 200°C (392°F) | BNTECHGO | | GXL | Stranded | Bare Copper | 20AWG - 8AWG | XLPE | 60V | 125°C (257°F) | Del City and Remington Industries |

UL1061 wire is a lightweight, flexible, and cost-effective solution for internal wiring in electronic devices, appliances, and control panels. Its thin-wall PVC insulation provides a small overall diameter, making it ideal for smaller pitch connectors where space is limited. With a 300V rating and good flexibility, it's easy to route in tight assemblies, though it lacks high-temperature resistance and is not suited for outdoor or high-voltage applications. This makes it our go-to choice for compact, low-to-medium voltage applications where precision and space efficiency are key. | Size | Overall Diameter (in) | Conductor Diameter (in) | Insulation Thickness (in) | Configuration | | :---- | :---- | :---- | :---- | :---- | | 28AWG | 0.035 | 0.0126 | 0.010 | 7/36 | | 26AWG | 0.039 | 0.0159 | 0.010 | 7/34 | | 24AWG | 0.044 | 0.0201 | 0.010 | 7/32 | | 22AWG | 0.051 | 0.0254 | 0.010 | 7/30 | | 20AWG | 0.057 | 0.0320 | 0.010 | 7/28 | | 18AWG | 0.068 | 0.0403 | 0.010 | 16/30 | | 16AWG | 0.080 | 0.0508 | 0.010 | 26/30 |

UL1007 stranded hookup wire is a versatile, durable, and widely used wire for internal wiring in electrical and electronic applications. With PVC insulation and a 300V rating, it offers better temperature resistance 105°C (221°F) than UL1061, making it suitable for a broader range of environments. Its moderate flexibility and durability make it ideal for control panels, appliances, and general-purpose wiring, though its thicker insulation means it's less suited for small-pitch connectors where space is a concern. We often choose UL1007 when a balance of flexibility, durability, and temperature resistance is needed, but not in ultra-compact applications. However, its large insulation thickness makes it incompatible with many small pitch connectors. | Size | Overall Diameter (in) | Conductor Diameter (in) | Insulation Thickness (in) | Configuration | | :---- | :---- | :---- | :---- | :---- | | 28AWG | 0.046 | 0.0126 | 0.015 | 7/36 | | 26AWG | 0.050 | 0.0159 | 0.015 | 7/34 | | 24AWG | 0.056 | 0.0201 | 0.015 | 7/32 | | 22AWG | 0.062 | 0.0254 | 0.015 | 7/30 | | 20AWG | 0.070 | 0.0320 | 0.015 | 10/30 | | 18AWG | 0.080 | 0.0403 | 0.015 | 16/30 | | 16AWG | 0.094 | 0.0508 | 0.015 | 26/30 | | 14AWG | 0.105 | 0.0641 | 0.015 | 41/30 |

Silicone wire is a high-flexibility, high-temperature hookup wire with tinned copper stranded conductors and silicone insulation, making it ideal for demanding environments. With a 600V rating and heat resistance up to 200°C (392°F), it outperforms PVC and XLPE-insulated wires in extreme conditions. Its exceptional flexibility makes it perfect for robotics, RC applications, electric vehicles, and high-movement assemblies, though its soft insulation is less abrasion-resistant than tougher materials like XLPE. We use silicone wire when heat resistance, flexibility, and high current capacity are critical factors. However, its large insulation thickness makes it incompatible with many small pitch connectors. | Size | Overall Diameter (in) | Conductor Diameter (in) | Insulation Thickness (in) | Configuration | | :---- | ----- | ----- | ----- | :---- | | 30AWG | 0.031 | 0.012 | 0.010 | 11/.08TS | | 28AWG | 0.047 | 0.014 | 0.017 | 16/.08TS | | 26AWG | 0.059 | 0.020 | 0.020 | 30/.08TS | | 24AWG | 0.063 | 0.023 | 0.020 | 40/.08TS | | 22AWG | 0.067 | 0.028 | 0.019 | 60/.08TS | | 20AWG | 0.071 | 0.036 | 0.017 | 100/.08TS | | 18AWG | 0.091 | 0.044 | 0.023 | 150/.08TS | | 16AWG | 0.118 | 0.057 | 0.030 | 252/.08TS | | 14AWG | 0.138 | 0.073 | 0.033 | 400/.08TS | | 12AWG | 0.177 | 0.095 | 0.041 | 680/.08TS | | 10AWG | 0.217 | 0.118 | 0.051 | 1050/.08TS | | 8AWG | 0.256 | 0.148 | 0.054 | 1650/.08TS | | 6AWG | 0.354 | N/A | N/A | 3200/.08TS |

GXL wire is a high-temperature, automotive-grade hookup wire with cross-linked polyethylene (XLPE) insulation, offering superior heat resistance up to 125°C (257°F), abrasion resistance, and chemical durability. It's tough yet flexible, though thicker and stiffer than UL1007. Ideal for automotive harnesses, engine compartments, and industrial systems, GXL is our choice when heat, vibration, and chemical exposure demand durability over compactness. | Size | Overall Diameter (in) | Conductor Diameter (in) | Insulation Thickness (in) | Configuration | | :---- | :---- | :---- | :---- | :---- | | 20AWG | 0.084 | 0.038 | 0.023 | 7/28 | | 18AWG | 0.094 | 0.048 | 0.023 | 16/30 | | 16AWG | 0.102 | 0.056 | 0.023 | 19/29 | | 14AWG | 0.116 | 0.070 | 0.023 | 19/27 | | 12AWG | 0.141 | 0.089 | 0.026 | 19/25 | | 10AWG | 0.174 | 0.112 | 0.031 | 19/23 | | 8AWG | 0.218 | 0.144 | 0.037 | 19/21 |

Multi-conductor cables bundle multiple insulated wires within a common jacket for simplified routing and enhanced protection.

**What is a Cable** A cable is a bundle of multiple insulated wires encased in an outer jacket. Cables may include shielding for EMI protection and fillers for structure and strength. **Commonly Used Cables** - **UL2464** – general-purpose signal cable. - **PVC Jacketed Multi-Conductor Cables** – cost-effective and compact. - **High-Flex Robotic Cables (Igus Chainflex, Belden Flex)** – for continuous motion and harsh environments. - **Shielded Communication Cables** – twisted pairs with foil/braid shielding for noise-sensitive applications. **Use Cases** - Chosen when space efficiency, EMI shielding, or long-distance durability is required. - Cables simplify organization, protect against abrasion, and reduce labor vs. sleeving multiple wires individually. - Individual wires remain preferable where unique routing, color coding, or flexibility in layout is needed. **MiniProto Practices** - Recommend cables for EMI-sensitive systems, long harness runs, or moving assemblies. - Select jackets (PVC, TPE, silicone) and shielding based on environmental and customer requirements.

Terminations create reliable electrical and mechanical connections between wires and equipment. Proper termination is critical for harness performance and longevity.

Connectors terminate wires to interface with boards, equipment, or other harnesses, providing both mechanical attachment and electrical continuity.

**What is a Connector** A connector terminates wires so a harness can interface with boards, equipment, or other harnesses. Connectors provide mechanical attachment and reliable electrical continuity. **Common Connector Types** - **Crimp Connectors**: open-barrel (automotive), closed-barrel (ring/spade), machined contacts. - **Soldered Connectors**: compact terminations where crimps aren't feasible. - **Ferrules**: used with stranded wires for screw clamps or terminal blocks. - **Lugs**: heavy-gauge ring/spade lugs for power distribution. **Use Cases / Selection** - Crimped terminations = most reliable, scalable, and standard practice. - Solder terminations = specialty or low-volume use. - Ferrules = improve reliability in terminal blocks. - Lugs = necessary for high-current applications. **MiniProto Practices** - Default to crimp connections whenever possible. - Validate terminal choice against both conductor gauge and insulation OD. - Follow IPC standards for all connector terminations.

Protection and finishing components safeguard the harness from environmental factors, provide organization, and enable identification and traceability.

Protective covers that bundle wires together while providing abrasion resistance and, in some cases, electromagnetic shielding.

**What is Sleeving** Sleeving is a non-shrinking protective cover that groups and protects wires in a harness. **Common Sleeving Types** - **PVC** – economical, basic protection. - **PET Expandable Sleeving** – abrasion resistance, expandable for easy assembly. - **EMI Sleeving** – conductive mesh to provide additional shielding. **Use Cases** - Used for bundling, abrasion protection, and aesthetics. - EMI sleeves supplement or replace cable shielding where required. **MiniProto Practices** - Apply sleeving when abrasion resistance or neat appearance is important. - Customers may specify sleeve type; if not, MiniProto selects based on durability needs.

Heat-activated tubing that shrinks to provide insulation, strain relief, sealing, and identification.

**What is Heatshrink** Tubing that shrinks when heated to provide insulation, strain relief, sealing, or identification. **Common Types** - **Single-Wall** – insulation only. - **Dual-Wall / Adhesive-Lined** – insulation plus sealing against moisture. - **Printable Heatshrink** – for labeling and traceability. **Use Cases** - Insulating bare splices or terminals. - Sealing connections against moisture or mechanical stress. - Providing durable wire and harness identification. **MiniProto Practices** - Use adhesive-lined heatshrink for all splices. - Apply printable heatshrink where durable labeling is required.

Connections that join wires mid-run to create branches or extend wire length.

**What is a Splice** A splice is a connection that joins wires mid-run to branch signals or power to multiple destinations. **Common Splice Methods** - **Solder Splice** – compact and reliable, default method at MiniProto. - **Crimp Splice** – used in some commercial harnesses. - **Ultrasonic Splice** – production method for high-volume applications. **Use Cases / Considerations** - Inline splices = compact and low-profile. - Lap splices = side-by-side joining. - Splices should not be placed in flex zones; stagger them to avoid bulk. - Allow sufficient clearance for heatshrink coverage. **MiniProto Practices** - Perform all splices per IPC/WHMA-A-620, with RoHS-compliant solder. - Cover all splices with adhesive-lined heatshrink for insulation and strain relief. - Maintain standard splice lengths per AWG to ensure strength and consistency.

Identification marking for wires, cables, and harnesses to enable traceability and simplify installation.

**What is a Label** Labels identify wires, cables, or harnesses for traceability, installation, and troubleshooting. **Common Labeling Methods** - Heatshrink labels (durable, permanent). - Wrap-around labels. - Printed markers. **Use Cases** - Mandatory for regulated industries (aerospace, medical, defense). - Useful for complex harnesses to simplify installation and maintenance. **MiniProto Practices** - Apply labels according to customer specifications. - Default to heatshrink labels where durability is essential.

Manufacturing quality wire harnesses requires precise processes, appropriate tolerances, and comprehensive testing procedures. Our manufacturing approach follows industry standards while maintaining the flexibility needed for custom applications. This section details our manufacturing processes, quality standards, and the steps we take to ensure every harness meets specification requirements.

Precise measurements and clear specifications are fundamental to manufacturing consistent, high-quality wire harnesses.

Manufacturing tolerances define acceptable variation in harness dimensions, ensuring quality while maintaining cost-effectiveness.

For harness lengths, MiniProto follows a modernized, tiered version of the IPC/WHMA-A-620 tolerance scheme designed for practical, automated manufacturing. ### Wire and Harness Length Tolerances (Metric) **MiniProto's default, unless specified.** | Wire Length Range | Standard Tolerance | Precision Tolerance | High Precision Tolerance | |------------------|-------------------|-------------------|------------------------| | ≤300 mm | ±12.5 mm | ±7.5 mm | ±2.5 mm | | >300 mm – 1500 mm | ±25 mm | ±15 mm | ±5 mm | | >1500 mm – 3000 mm | ±50 mm | ±30 mm | ±10 mm | | >3000 mm – 7500 mm | ±75 mm | ±50 mm | ±25 mm | | >7500 mm | ±2.5% | ±1.5% | ±1.0% | | **Pricing Surcharge** | +0% | +15% | +40% | Tolerancing on other features is defined on a feature by feature basis throughout this documentation. ### Why Bilateral Tolerances? Because unilateral tolerances (+X / -0) are a relic of manual processes that no longer make sense in modern manufacturing. - They were designed for hand-cut wire—an outdated process in today's automated manufacturing environments. - They increase scrap and cost – forcing unnecessary overcorrection that serves no real function. In short, unilateral tolerances are outdated, arbitrary, and inefficient. That's why we use bilateral tolerances, which actually align with real-world production and measurement processes. ### Cost & Design Considerations #### Design Tips - **Tighter tolerances increase costs.** Precision is expensive, and overly strict tolerances can significantly drive up manufacturing costs with little to no functional benefit in many typical applications. - **Design for real-world manufacturability.** Advanced manufacturing tools naturally produce variation in both directions, making bilateral tolerances the practical choice. - **Looser is better (when it works).** Always design for the loosest tolerance that still meets your fit and function requirements. #### Specifying Special Tolerances - **Call out critical tolerances.** If your design requires a tighter tolerance than our standard scheme, clearly note this in your drawings or design notes. - **We'll review and price accordingly.** Our team will assess your request and provide any necessary pricing adjustments based on the manufacturing impact. Our tolerances are built for real-world manufacturability, not outdated constraints from a bygone era.

Reference points from which all harness branch lengths are measured, ensuring dimensional accuracy.

A distance datum is a reference point from which all harness branch lengths are measured. In our drawings we designate a **zero datum** (often the centre of the first connector or the end of the main trunk) and dimension each leg's cut length from that point. Using consistent datums eliminates cumulative errors when multiple branches stem from a common node. When specifying a harness, identify where you want the datum and measure each segment straight along the intended routing path. If branches terminate at different locations on the same connector, note the pin positions to avoid confusion. *Proposed graphic: a simplified harness drawing with a highlighted zero datum and arrows showing how each branch length is measured from it.*

Wire and cable preparation is the first step in harness assembly, involving cutting, stripping, and preparing conductors for termination.

Removing insulation from wire ends to prepare conductors for termination while maintaining conductor integrity.

Stripping is the removal of insulation from the end of a conductor so that it can be terminated. Most crimp terminals, solder cups and wire nuts require a specific strip length to ensure that the bare conductor fills the barrel without leaving exposed strands. During assembly the wire is cut to the overall length and then stripped using automatic cutters that clamp and pull off the insulation. Proper stripping should not nick or score the conductor strands, as this weakens the wire and increases resistance. For multi‑conductor cables, only the outer jacket is removed at branch points while the individual conductor insulations remain intact until termination. Always consult the connector manufacturer's datasheet for the recommended strip length; if unspecified, leave enough bare conductor to fill the wire barrel plus 0.5 mm for inspection.

Wire termination is the process of connecting wire ends to connectors, terminals, or other components to complete the electrical circuit.

Termination methods create electrical and mechanical connections between conductors and connectors, forming the functional harness.

Mechanical compression of terminals onto conductors to create reliable, gas-tight electrical connections.

Crimping compresses a terminal barrel around the conductor to create a low‑resistance joint. During this process, the barrel is deformed plastically so that it flows between the individual strands, forming a gas‑tight connection that resists vibration. IPC‑620 defines requirements for crimp height, width and bellmouth (flared end), which we monitor using go/no‑go gauges. For best results: - Use the correct applicator or die set matched to the terminal series and wire gauge. Mismatched tooling can cut strands or leave the crimp loose. - Confirm the strip length so that the conductor fully fills the wire barrel but no bare strands protrude beyond the crimp. - Inspect crimped joints visually—look for evenly compressed barrels, no cracks, proper bellmouth and proper positioning relative to the insulation support. - Perform pull‑force tests on sample crimps to verify that they meet manufacturer specifications. Crimps should not be soldered after compression, as the heat can anneal the metal and compromise the joint.

Creating metallurgical bonds between conductors and terminals using heat and solder alloy.

Soldering in harness production is used for terminations that cannot be crimped, such as solder cups, posts or direct board attachment. The goal is to form a metallurgical bond between the conductor and terminal without overheating the wire insulation. Our soldering process typically involves: 1. **Tinning.** Stripped wire ends are lightly coated with solder and flux to improve wetting and prevent oxidation. Excess solder is wicked off to avoid lumps. 2. **Insertion and heating.** The tinned conductor is inserted into the cup or wrapped around the post. Heat is applied to the terminal, not the solder, until the solder flows freely into the joint. IPC‑620 specifies that solder should fully fill the cup or wrap and form a smooth, concave fillet. 3. **Inspection.** Completed joints are checked for proper fillet shape, absence of voids or cracks, and minimal solder protrusion. Insulation clearance is verified to ensure no burning or melting has occurred. Because solder joints are rigid, additional strain relief is typically provided with heat‑shrink tubing or epoxy potting. Flux residues are cleaned off if they could promote corrosion or electrical leakage.

When wires must be joined mid‑run (for example, to branch off a sensor wire), a splice is used. Two techniques are common: - **Crimped butt splices:** A metal sleeve is crimped around the stripped ends, forming a cold‑welded connection. This method is preferred for its strength and repeatability. Heat‑shrink tubing is applied over the splice for insulation and strain relief. - **Soldered splices:** The conductors are twisted together, soldered and then insulated with heat‑shrink tubing. Solder splices offer a lower profile and are sometimes used in applications with limited space. Care must be taken to prevent solder wicking under the insulation, which can create a stiff "solder spike" that breaks under flexing. Regardless of the method, ensure that the splice is protected against moisture and mechanical stress and that it does not increase the bundle diameter beyond what your sleeve or connector can accommodate.

Many circular and rectangular connectors—such as MIL‑spec 38999 or D‑subminiature connectors—are supplied with solder cup contacts. Each contact has a small cup into which the stripped conductor is inserted. When heated, solder flows into the cup and up into the wire strands, forming a solid bond. Proper technique requires filling the cup completely without overflowing onto adjacent contacts. A good solder cup termination exhibits a concave fillet and no exposed strands. After soldering, the wire should be secured with a strain‑relief clamp or a potting compound to prevent movement from stressing the solder joint.

Surface‑mount termination is less common for harnesses but may be used when wires need to be attached directly to a printed circuit board without through holes. In this case, wires are terminated with solder tabs or pre‑attached eyelets that are placed onto solder paste and reflowed along with the board assembly. Alternatively, flexible printed circuits (FPCs) can replace traditional wires for compact, high‑density interconnects. SMT harnesses require careful design of pads, solder mask openings and strain‑relief features to ensure reliability.

Through‑hole termination refers to inserting wire leads into plated holes in a printed circuit board and soldering them from the opposite side. This method provides strong mechanical support because the wire is anchored by the hole wall. Harness leads intended for thru‑hole boards are typically pre‑tinned, inserted through the board, bent slightly to hold them in place, and then wave‑soldered or hand‑soldered. After soldering, excess lead length is trimmed flush. It is important to maintain proper clearance between adjacent leads and to avoid wicking solder up the insulation.

Specialized techniques for terminating multi-conductor cables while maintaining signal integrity.

Cable termination involves connecting multi-conductor cables to connectors or terminal blocks while maintaining signal integrity and mechanical reliability.

Final assembly steps that organize, protect, and prepare the harness for installation and use.

Organizing and securing multiple conductors into a cohesive, manageable harness assembly.

Bundling refers to organising wires or cables into a coherent group so that they can be routed together. After termination, conductors are arranged in the specified order and secured with cable ties, lacing cord, or strategically placed heat‑shrink tubing. Proper bundling ensures that branches exit at the correct lengths and positions and that the harness remains flexible. When bundling: - Start from the datum and work outward, aligning the wires so that the final connectors face the correct orientations. - Use soft‑edge cable ties or waxed lacing to avoid cutting into insulation. Do not over‑tighten ties; harnesses should remain slightly pliable. - Place ties at regular intervals (typically every 150 mm) or where branches split. Tie spacing may be reduced for small‑diameter bundles. - Trim the ends of cable ties flush to avoid sharp edges. Once bundling is complete, sleeving or heat‑shrink tubing may be applied over the bundle for additional protection. For a practical cable-or-bundle decision flow, see our <a href="/guides/how-to-bundle-a-wire-harness" class="font-semibold text-mp-orange hover:text-mp-blue">wire harness bundling guide</a>.

Applying protective sleeving to bundled harnesses for abrasion resistance and professional appearance.

Applying sleeving is one of the last steps before final testing. For braided sleeving, the sleeve is expanded and slid over the bundle. Heat‑shrink boots are then placed at each end and shrunk to grip both the sleeve and the underlying wires, preventing the braid from unravelling. For convoluted tubing, the tubing is slit along its length; the harness is laid into the channel and the tube is closed, sometimes with an additional wrap to secure it. Cables requiring shielding may have a separate braid or foil applied under the outer sleeve—see the Shielding section for details. Always ensure that the sleeve length accounts for any branch break‑outs and that it does not interfere with connector backshells or mounting hardware.

Comprehensive inspection and testing procedures ensure every harness meets specification requirements before delivery.

Systematic inspection and electrical testing procedures verify harness quality and functionality.

Visual inspection verifies that the harness meets workmanship standards. Inspectors check: - **Connector integrity.** All terminals are fully seated in their housings, retaining latches are engaged and polarising keys are oriented correctly. - **Wire insertion.** There should be no exposed conductor outside the crimp or solder cup; insulation should enter the insulation support of the terminal. - **Label legibility.** All labels are present, properly located and readable; colours and text match the drawing. - **Bundling and sleeving.** Ties are evenly spaced and not over‑tightened, sleeving is intact without frays, and heat‑shrink boots have fully recovered. - **Mechanical damage.** Check for cuts, nicks or abrasions in the insulation. Strain‑relief clamps and backshells should be secure. Harnesses that fail visual inspection are reworked or scrapped depending on the defect severity.

After visual inspection, each harness undergoes electrical testing. A continuity tester or custom test board is used to verify that every pin‑to‑pin connection matches the wiring diagram and that there are no opens, shorts or crossed circuits. The board can detect mis‑wires and partial breaks by measuring continuity and resistance. For high‑current harnesses, we may perform a resistance check using a micro‑ohmmeter to ensure that the total resistance is within specified limits. In some cases, hipot (high‑potential) tests are conducted to confirm insulation integrity. Only harnesses that pass all tests are approved for packaging.

Final packaging and shipping procedures ensure harnesses arrive safely and ready for installation.

Protective packaging and identification labeling for safe transit and easy traceability.

Packaging is designed to protect the harnesses during transit and to provide traceability: - **Coiling or spooling.** Short harnesses are coiled into loops of large diameter to avoid kinks; long harnesses may be wound onto spools. Anti‑static bags or bubble wrap are used as required. - **Labelling.** Each harness is tagged with a barcode label containing the part number, revision, date code and serial number. The outer packaging also carries a packing list identifying the contents and quantity. - **Documentation.** Test reports or certificates of conformance are included when requested. Drawings or configuration printouts may accompany the shipment to aid in installation. Packaging personnel ensure that connectors are capped if necessary and that sensitive components are protected from electrostatic discharge. Shipping cartons are sized appropriately and cushioned to prevent damage.

Worldwide shipping options with tracking and documentation for domestic and international orders.

We ship harnesses worldwide via major carriers. Standard shipping methods include ground, two‑day and overnight services; expedited options are available for urgent orders. Lead time begins once the quote is approved and all materials are on hand. International shipments are accompanied by commercial invoices and any required customs documentation. For large or sensitive harnesses, we may recommend freight service or custom crating. Please notify us of any special handling instructions (such as orientation requirements or temperature limits) when placing your order.

MiniProto provides comprehensive support for your wire harness projects, from initial consultation through post-delivery service. Our support policies are designed to ensure your project success and long-term satisfaction. This section covers our terms of service, warranty policies, and procedures for reorders and modifications.

Our Terms of Service outline the responsibilities of both MiniProto and the customer. In summary: - **Quotations and orders.** Quotes are valid for 30 days, or until material costs change by more than 10% due to forces beyond our control. Orders are accepted upon receipt of a purchase order and payment terms as agreed. Changes to an order (such as design revisions or quantity adjustments) may affect price and lead time. - **Payment.** Full payment is required before production begins. We accept credit card (preferred for orders under $10,000) and ACH. Credit terms (Net 15/30) are available for repeat customers with established accounts - never on first orders. - **Lead time.** Estimated ship dates are based on current material availability and manufacturing load. MiniProto is not liable for delays caused by carriers, supplier shortages, or force majeure events. - **Customer supplied materials.** If you provide connectors or special components, you are responsible for ensuring they arrive on time and meet specifications. We are not responsible for defects arising from customer‑provided parts. Please account for overage when sending parts - contact us for recommended quantities. - **Shipping.** Orders ship FOB origin from Kingston, NY. Title and risk of loss transfer to customer upon shipment. Claims for shipping damage must be filed with the carrier. - **Liability.** MiniProto is not liable for how harnesses are used or any failures, damages, or injuries resulting from their use. Our liability is limited to the value of your order. We are not responsible for indirect, incidental, or consequential damages.

MiniProto warrants that harnesses will be free from defects in workmanship for 90 days from the date of shipment. This warranty covers manufacturing defects such as poor crimping, mis‑wiring or faulty soldering. It does not cover damage caused by improper installation, misuse, modification or environmental conditions outside the specified ratings. At our discretion, we will repair, replace or refund defective products. To initiate a warranty claim, contact support with your order number, a description of the issue and photographs if possible.

Every shipment includes: - **Completed harnesses** built to your submitted design or drawing, with all connectors, labeling and sleeving installed. - **Quality documentation** such as a test report or certificate of conformance (when requested) showing that the harness passed visual and electrical inspection. - **Packing list and identification labels** detailing the part number, revision, quantity and manufacturing date. - **Ancillary hardware** such as mounting hardware or mating connectors if they were included in the order. We encourage you to inspect the harnesses upon receipt and store them in a clean, dry environment until installation.

If you discover an issue with a harness (e.g., incorrect wiring, damaged connector or mislabeled wire), please follow these steps: 1. **Document the problem.** Immediately take clear photographs and describe the defect in detail. Include the order number, part number and serial number. 2. **Contact support.** Send the documentation to our customer service team via email or through the support portal. We will respond within one business day. 3. **Return authorization.** If a physical return is necessary, we will issue a return authorization (RMA) number and provide shipping instructions. Do not return products without an RMA. 4. **Resolution.** Once received, we will evaluate the harness and determine whether the issue is covered under warranty. If so, we will repair or remake the harness at no cost. If not, we will provide a quote for rework or adjustment.

Reordering is simple: 1. **Use the same part number.** Every custom harness is assigned a unique part number and revision. Referencing this part number ensures that we build to the correct specifications. 2. **Specify quantity and delivery date.** Let us know how many units you need and when you need them. We will quote price and lead time based on the current material inventory and production schedule. 3. **Confirm any changes.** If you need to revise the design (e.g., change a connector or wire length), submit an updated drawing or Config Tool file. Revisions may change the part number and will require a new quote. 4. **Place the order.** Send us a purchase order or order through the online portal. We will acknowledge the order and begin production per our standard process.

Quick reference materials for wire harness specification and design. These charts and abbreviations are commonly used in the wire harness industry and provide essential information for accurate specification. Use these references when creating drawings, placing orders, or communicating harness requirements.

It is often helpful to abbreviate colors when working with wires and cables. To avoid confusion, we abide by IEC60757 for color abbreviations shown below: | Color Name | Two Letter Abbreviation | |-----------|------------------------| | Black | BK | | Blue | BU | | Brown | BN | | Gold | GD | | Green | GN | | Grey | GY | | Orange | OG | | Pink | PK | | Red | RD | | Silver | SR | | Turquoise | TQ | | Violet | VT | | White | WH | | Yellow | YE | ### Multi-Color Combinations Explanation The IEC 60757 standard defines how to represent multi-color electrical wiring using specific formatting rules. Below are the key methods for designating multi-color wires: #### 1. Multiple Colors on a Single Wire If a wire has multiple colors applied together (such as stripped wires), the color codes are written in sequence without separators. Example: - A wire that is both Red and Blue is designated RDBU - A wire that is Black, Brown, Grey, Blue, and Green-Yellow is designated BKBNGYBUGNYE #### 2. Green-Yellow for Protective Earth (Special Case) - The combination of Green and Yellow is reserved for protective earth grounding conductors and must always be designated as GNYE. - Green and Yellow must not be used together in any other context or rearranged. Example: - A protective earth wire is always GNYE, never YEGN or split into separate Green and Yellow designations. #### 3. Alternating Colors on the Same Wire If a component alternates between two colors, such as in color-changing indicators, the colors are separated by a forward slash "/". Example: - An LED that flashes Blue and White alternately is designated BU/WH #### 4. Different Colors for Separate Conductors in a Cable For cables that contain multiple conductors with different colors, the colors are separated by a plus sign "+". Example: - A cable containing Black, Brown, Grey, Blue, and Green-Yellow conductors is designated BK+BN+GY+BU+GNYE - If a connector has multiple terminals, each with a different color, the colors are listed with the "+" separator to indicate they are distinct conductors within the same assembly. #### Summary of Multi-Color Representation Rules: 1. Multiple solid colors on a wire: Colors are written in sequence (e.g., RDBU for a Red-Blue wire). 2. Green-Yellow for Protective Earth: Always GNYE (never rearranged or separated). 3. Alternating colors on a component: Use "/" (e.g., BU/WH for an LED alternating between Blue and White). 4. Different conductors in the same cable: Use "+" (e.g., BK+BN+GY+BU+GNYE for a multi-conductor cable).

For accurate wire specification, refer to our comprehensive [AWG ↔ mm² conversion chart](https://docs.google.com/spreadsheets/d/19tUpupGNO1kgyuXSIghCePk2Q2k9F5P86qhNwlZQWz0/edit?gid=616318744#gid=616318744) which includes detailed specifications for common wire gauges used in harness manufacturing.