1.3 Connector Families & Pinouts
AIn cable harness'sharness structuremanufacturing, documentation is as critical as the physicaldesign layoutitself. A harness only performs as intended if every detail—wire size, connector orientation, strip length, and organizationlabel placement—is communicated without ambiguity. Drawings, bills of its wires, connectors,materials, and protectivewire coverings.tables Theserve structureas the common language between engineering, production, and quality teams, ensuring that builds are consistent, testable, and free from interpretation errors. When all documents align, the result is designeda harness that can be built right the first time, even by someone new to fit the specific geometric and functional needs of an application, ranging from a simple point-to-point connection to a complex, multi-branched network.Choosing contacts, crimps, seals, and keying to avoid mis-mates.
Connectors are the handshake between harness and hardware, and a poor choice can cause leaks, mis-mates, or electrical noise. The right family depends on the environment, current, mating cycles, and service needs—not just what’s in stock. Details like contact type, plating, seals, backshells, and keying directly affect reliability, while clear pin numbering and grounding practices keep both assembly and testing straightforward. Mechanical coding, color cues, and CPA/TPA locks help prevent mix-ups in the field. When selection, crimping, sealing, and documentation all align, connectors become a quiet point of certainty in the harness—secure, repeatable, and trouble-free.product.
1.3.1 Cable Harness TypesFirst decide the job, then the family
A cable harness's structure is the physical layout and organization of its wires, connectors, and protective coverings. The structure is designed to fit the specific geometric and functional needs of an application, ranging from a simple point-to-point connection to a complex, multi-branched network.
Common Cable Harness Structures
1. Point-to-Point Harness (Jumper Cable)
This is the simplest structure, consisting of one or more wires connecting two points directly. It has a single origin and a single destination.
- Structure: A straight bundle of wires with a connector at each end.
- Example: A simple jumper cable used to connect a power supply to a circuit board or a USB cable connecting a phone to a charger. It serves one purpose: to create a direct link between two components.
2. Multi-Branch Harness
This is the most common type of complex harness. It features a main "trunk" of bundled wires from which several smaller "branches" or "breakouts" emerge. Each branch routes wires to different connection points.
- Structure: Similar to a tree, with a thick main trunk and smaller branches extending out. The length and direction of each branch are precisely defined to reach specific components.
- Example: An automotive engine harness. The main trunk runs along the engine block, and individual branches split off to connect to the alternator, fuel injectors, various sensors, and the main computer (ECU).
3. Flat Ribbon Cable Harness
This structure consists of multiple wires laid parallel to each other and bonded together to form a flat, wide cable. It is primarily used for internal data connections where space is limited and organization is key.
- Structure: Wires are arranged in a single plane, resembling a ribbon. The connectors are typically insulation-displacement connectors (IDCs) that can be quickly crimped onto the cable.
- Example: The internal wiring in a computer connecting the motherboard to the hard drive or other peripherals. Its flat design allows it to be neatly folded and routed in tight spaces while keeping the data lines organized.
4. Ribbon-Round Cable Harness
This is a hybrid structure that combines the benefits of flat ribbon and traditional round cables. It starts as a flat ribbon cable, which is then folded and jacketed to create a round profile.
- Structure: Internally, it's a flat ribbon cable, allowing for easy mass termination with IDC connectors. Externally, it has a round jacket, which provides better EMI/RFI shielding and durability than a flat cable.
- Example: Used in medical or aerospace equipment where a high-density connection is needed inside a device, but the cable must exit the chassis as a durable, shielded round cable.
5. Hybrid Cable Harness
This type of harness combines different types of wires and cables within a single assembly. It's designed to transmit power, data, and signals simultaneously.
- Structure: A single bundled harness containing a mix of wire types, such as twisted pairs for data, coaxial cables for video or RF signals, and standard power wires. Each wire type is chosen for its specific function.
- Example: A robotic arm harness. It needs to deliver high current to the motors, carry sensitive data from encoders and sensors, and transmit video from a camera, all through one integrated and flexible assembly.
6. Overmolded Cable Harness
In this structure, the area where the cable meets the connector is encapsulated in a solid block of molded plastic (like PVC or thermoplastic elastomer). This creates a very durable and sealed connection point.
- Structure: The connector and the end of the cable are seamlessly integrated. The overmold provides excellent strain relief and environmental sealing (IP rating).
- Example: A heavy-duty industrial sensor cable or a USB charging cable. The molded ends prevent the wires from breaking at the connector, which is a common point of failure, and protect the connection from moisture and dust.
Pick the connector family by environment, current, mating cycles, and mis-mate risk—not by what’s in the drawer.
Rule of thumb: if the harness can be unplugged by a customer or field tech, prefer sealed families with secondary locks and clear keying.
1.3.2 Contacts & plating—pick for current, cycles, and noise
Crimp discipline: use manufacturer dies & applicators, verify crimp height and pull force, and crimp insulation support where provided.
1.3.3 Cable Harness Components Seals, backshells & IP rating—dry inside, always
A cable harness is an engineered assembly of electrical conductors and components that transmit signals or power. Its components can be categorized into four main groups: conductors, termination and connection components, sealing and mechanical protection components, and fastening and identification components.
1.3.3.1 Conductors
These are the core components responsible for transmitting electrical current or data.
Wire/Cable: The primary element. A wire consists of a conductor, typically made of Electrolytic Tough Pitch (ETP) copper or a copper alloy, chosen for its high conductivity. The conductor can be a single solid core or multiple strands, which provide flexibility. The conductor is encased in an insulation material, such as PVC, XLPE (Cross-linked Polyethylene), or high-performance fluoropolymers like PTFE (Teflon), which provides dielectric strength and protection. The choice of insulation is dictated by the required voltage rating, temperature class (e.g., T3 for 125°C), and resistance to fluids and abrasion.
Strand Types:
Concentric Strand: A concentric stranded conductor consists of a central wire or core surrounded by one or more layers of helically laid wires. Each layer after the first has six more wires than the preceding layer. Except in compact stranding, each layer is usually applied in a direction opposite to that of the layer under it. If the core is a single wire and if it and all of the outer strands have the same diameter, the first layer will contain six wires; the second, twelve; the third, eighteen; etc.
Bunch Strand: The term bunch stranding is applied to a collection of strands twisted together in the same direction without regard to the geometric arrangement.
Rope Strand: A rope stranded conductor is a concentric stranded conductor each of whose component strands is itself stranded. A rope stranded conductor is described by giving the number of groups laid together to form the rope and the number of wires in each group.
Sector Conductor: A sector conductor is a stranded conductor whose cross-section is approximately the shape of a sector of a circle. A multiple conductor insulated cable with sector conductors has a smaller diameter than the corresponding cable with round conductors.
Compact Strand: A compact stranded conductor is a round or sector conductor having all layers stranded in the same direction and rolled to a predetermined ideal shape. The finished conductor is smooth on the surface and contains practically no interstices or air spaces. This results in a smaller diameter.
Compressed Strand: Compressed conductors are intermediate in size between standard concentric conductors and compact conductors. A comparison is shown below:
1.3.3.1.1 Wire Cable Types
Single-Core Cable
A single-core cable consists of a single conductor surrounded by a layer of insulation and, in some cases, an outer jacket. The conductor is the current-carrying element, usually made of copper or aluminum. The insulation prevents direct contact with other conductors or the environment, ensuring electrical safety and signal integrity.
- Construction: One central conductor.
- Application: Commonly used in power distribution, both AC and DC systems, where separate conductors for different phases, neutral, or earth are run independently. For example, wiring for residential power circuits or high-voltage transmission lines.
Multi-Core Cable
A multi-core cable contains two or more insulated conductors bundled together within a single outer jacket. These individual conductors are called 'cores'. This configuration simplifies installation by consolidating multiple wires into one manageable assembly.
- Construction: Multiple insulated conductors laid up (often twisted or parallel) and enclosed in a common protective sheath.
- Application: Ubiquitous in control systems, instrumentation, data communication, and multi-phase power applications where multiple connections are needed between two points (e.g., control panels, network wiring, and appliance power cords).
Shielded Cable
A shielded cable is an electrical cable that includes a conductive layer, or shield, to protect the inner conductors from electromagnetic interference (EMI). EMI, also known as radio-frequency interference (RFI), can degrade signal quality and disrupt data transmission. The shield is typically grounded and works by reflecting or absorbing the interfering noise.
- Construction: The shield can be a braided mesh of copper wires, a solid or laminated conductive foil (like aluminum foil), or a combination of both. It is positioned around the insulated conductor(s) but beneath the outer jacket.
- Application: Essential for data cables (like Ethernet), audio/video cables (like coaxial cables), and instrumentation wiring in environments with high electrical noise, such as industrial plants or near motors and transformers.
Flat Cable
A flat cable consists of multiple conductors running parallel to each other in the same flat plane. As a result, the cable has a wide and flat profile. The conductors are individually insulated.
- Construction: Parallel conductors laminated between flexible insulating materials.
- Application: Frequently used in applications requiring high flexibility and space efficiency, such as in robotics, automated equipment, and elevators, where repeated bending and movement occur.
Ribbon Cable
A ribbon cable, also known as a multi-wire planar cable, is a specific type of flat cable where the conductors are arranged in a precise, parallel, and evenly spaced manner, resembling a ribbon. This design allows for mass termination with insulation-displacement connectors (IDCs).
- Construction: Multiple small-gauge wires running parallel, bonded together by a flexible insulating material.
- Application: Widely used for internal interconnections within electronic equipment, such as connecting peripherals to a motherboard inside a computer, due to its space-saving design and ease of termination.
Coaxial Cable
A coaxial cable is designed to transmit high-frequency signals with low loss. It features a central conductor surrounded by an insulating dielectric, which is then enclosed by a metallic shield (braid or foil) and an outer insulating jacket. This concentric construction creates a controlled electromagnetic field, minimizing signal radiation and susceptibility to EMI.
- Application: Used for cable television (CATV), broadband internet, and radio frequency (RF) applications.
Copper Calculations in Cables
Copper is an essential part of wires and cables and is listed on the stock exchange.
The name DEL is derived from the German exchange "Deutsche Elektrolytkupfer Notiz für Leitzwecke". Based on the official quotation at the LME (London Metal Exchange), the value of the DEL list is calculated every trading day. The standard price for automotive cables is based on a copper value of 150.00 EUR / 100 kg.
Copper Weight [g / km] x ( ( Medium DEL [EUR / 100 kg] + 1 % procurement costs ) - copper base [EUR / 100 kg] ) / 100 = Copper Surcharge [EUR / km]
Example Calculation of Copper Surcharge
The total price will be the quoted price in the online shop + copper surcharge (in EUR / km):
9.60 [kg / km] x ( ( 590.00 [EUR / 100 kg] + 5.90 [EUR / 100 kg] ) - 150.00 [EUR / 100 kg] ) / 100
= 42.81 [EUR / km]
19.2.2.1.2 Wire Insulations
Wire insulation is the non-conductive material surrounding a wire's conductor. Its primary job is to prevent short circuits by keeping the conductor from touching other conductors or conductive surfaces. It also protects the wire from environmental factors like moisture, chemicals, and physical damage.
The selection of the right insulation is a critical engineering decision that directly impacts the safety, reliability, and lifespan of a cable harness.
1.3.3.2 Selection Criteria ⚙️
Choosing the correct insulation involves balancing performance requirements and cost. The main criteria are:
- Electrical Requirements: The insulation must have a high enough dielectric strength to withstand the system's voltage without breaking down.
- Temperature Range: It must perform reliably within the expected operating temperature range, from the coldest startup condition to the hottest peak temperature, without becoming brittle or melting.
- Mechanical Stress: The material must be tough enough to handle the physical demands of the application, including resistance to abrasion, cutting, vibration, and flexing.
- Chemical and Fluid Resistance: It must not degrade when exposed to fluids it might encounter, such as oil, fuel, hydraulic fluid, or solvents.
- Environmental and Safety Requirements: The application may have specific safety rules, such as requiring materials that are halogen-free or UV resistant.
19.2.2.1.4 Common Insulation Materials & Chemical Structure
Different chemical structures give insulation materials their unique properties.
- PVC (Polyvinyl Chloride): A vinyl polymer thermoplastic. It's the most common and cost-effective insulation. It has good general-purpose resistance to moisture and abrasion but has a limited temperature range and contains halogens.
- XLPE (Cross-linked Polyethylene): A polyolefin thermoset. The "cross-linking" process creates strong chemical bonds between polymer chains, giving it superior thermal stability, toughness, and chemical resistance compared to standard polyethylene or PVC. It's widely used in automotive and industrial applications.
- Silicone: An inorganic polymer. Its silicon-oxygen backbone makes it extremely flexible and gives it an excellent, wide temperature range (e.g., -60°C to 200°C). However, its mechanical strength is poor, meaning it has low resistance to cutting and abrasion.
- PTFE (Teflon) & other Fluoropolymers (FEP, ETFE): These are fluorocarbon-based polymers. The strong carbon-fluorine bonds give them exceptional resistance to high temperatures and chemicals. They also have a very low coefficient of friction, making them easy to pull through conduits. They are considered high-performance materials and are used in demanding aerospace and industrial applications.
19.2.2.1.5 Special Applications and Formulations
- Halogen-Free (LSZH - Low Smoke Zero Halogen): Standard insulators like PVC contain halogens (chlorine). When they burn, they release thick, toxic, and corrosive smoke. Halogen-free materials are used in enclosed or poorly ventilated spaces like aircraft, ships, subways, and data centers. In a fire, they produce very little smoke and no toxic halogenated gases, improving safety and evacuation.
- Sulfur-Free: This is a highly specific requirement for high-temperature applications that use silver-plated copper wire. At high temperatures, any sulfur present in the insulation material can react with the silver plating, forming silver sulfide (tarnish). This corrosion degrades the conductor, increases resistance, and can lead to connection failure. Therefore, the insulation used with silver-plated wire must be certified as sulfur-free.
- UV Resistance: For cables used outdoors, the insulation must contain additives to resist degradation from ultraviolet (UV) radiation from the sun. Without this protection, the material would become brittle and crack over time.
19.2.2.2 Connectors
Connectors are critical electromechanical devices in cable harnesses, providing a separable interface for electrical circuits. They allow harnesses to be easily connected to and disconnected from equipment, enabling modular design, simplified manufacturing, and efficient maintenance.
Connectors in cable harnesses are terminated using several methods, but the two most prevalent are crimp terminals and insulation-displacement connectors (IDC). Each method offers distinct advantages in reliability, production speed, and application suitability.
19.2.2.2.1 Connector Anatomy
A typical industrial connector isn't just a simple plug; it's an assembly of precision components designed to maintain a reliable connection in demanding environments.
- Housing: The outer shell that encases the internal components. It provides mechanical protection, alignment during mating, and electrical insulation. Housings are typically made from engineered polymers (like PBT or Nylon) for insulation and light weight, or metals (like aluminum or stainless steel) for durability and EMI shielding.
- Terminals / Contacts: These are the conductive elements within the housing that make the actual electrical connection. They are precision-machined from highly conductive copper alloys and are often plated with materials like gold or tin. Gold plating provides excellent corrosion resistance and low contact resistance, crucial for low-level signals, while tin is a cost-effective choice for power applications.
- Seals & Gaskets: In industrial settings, connectors must often protect against moisture, dust, and chemicals. Elastomeric seals (made from silicone, neoprene, or Viton) are integrated into the connector's design to achieve a specific level of environmental protection. This is quantified by an Ingress Protection (IP) rating, such as IP67, which signifies the connector is dust-tight and can be submerged in water.
- Locking Mechanism: To prevent accidental disconnection due to vibration or pulling, industrial connectors feature robust locking mechanisms. Common types include:
- Threaded Coupling: A screw-on mechanism providing a very secure, vibration-resistant connection.
- Bayonet Lock: A quick, push-and-twist mechanism common in military and RF connectors.
- Push-Pull Latch: Allows for quick connection and disconnection but provides a strong lock that can only be released by pulling on the connector's outer sleeve.
Connectors in cable harnesses are terminated using several methods, but the two most prevalent are crimp terminals and insulation-displacement connectors (IDC). Each method offers distinct advantages in reliability, production speed, and application suitability.
Crimp Connectors
A crimp connector is a type of solderless electrical connection. It uses a specialized tool to mechanically deform a metal terminal around a wire's conductor, creating a secure, gas-tight joint. This method is widely used because it's fast, reliable, and creates a strong mechanical and electrical bond.
This process has two key parts:
- Conductor Crimp: The main barrel of the terminal is squeezed tightly around the metal strands of the wire. The intense pressure forms the wires and the terminal into a single, solid mass, creating a cold weld. This forms a reliable, low-resistance electrical connection that prevents oxygen and moisture from getting in and causing corrosion.
- Insulation Crimp: A second part of the terminal is lightly crimped around the wire's insulation. This doesn't make an electrical connection; instead, it acts as strain relief, protecting the delicate conductor strands from breaking due to vibration or movement.
Key Components;
- Wire: The conductor that needs to be terminated. The end must be stripped of its insulation to a precise length.
- Crimp Terminal: A specially designed metal piece (often tin-plated copper) that receives the wire.
- Crimping Tool: A specialized tool with dies shaped to match the terminal. Using the correct tool is critical for a proper crimp; using pliers or the wrong tool will result in a failed connection.
Insulation-Displacement Connectors (IDC)
IDC is a connection method where the terminal has sharp, precisely engineered tines or blades that pierce directly through the wire's insulation to make contact with the conductor. This eliminates the need for wire stripping, dramatically speeding up the assembly process.
- Process:
- An insulated wire is placed into a slot on the connector.
- A specialized tool or press pushes the wire into the slot, causing the sharp tines to displace the insulation and make a secure electrical connection with the conductor.
- Characteristics:
- Speed & Automation: The elimination of wire stripping makes IDC ideal for high-speed, automated mass termination, especially for multi-conductor ribbon cables.
- Specific Design: IDC connectors are designed for specific wire gauges and insulation types (typically solid or stranded PVC-insulated wires).
- Common Applications: Widely used inside computers (e.g., floppy and PATA hard drive cables), networking, and telecommunications equipment where high-density, low-cost connections are required.
19.2.2.2 Terminals
Terminals are the metal components at the ends of wires that create a secure and reliable point for an electrical connection. They are the crucial interface between the wire's conductor and the rest of the electrical system, whether it's another wire, a screw post, or the pin in a connector.
19.2.2.2.1 Crimping Terminals
These are the most common type of terminal found inside multi-pin connectors. They are precision-stamped components designed to be crimped onto a wire and then inserted into a connector housing.
- Structure: They typically have an "open barrel" or "F-crimp" design with two sets of wings. One set is crimped around the bare wire conductor to create a gas-tight electrical bond, while the second set is crimped around the wire's insulation to provide mechanical strain relief.
- Usage: Used inside multi-pin plastic connectors in nearly all industries, including automotive, aerospace, and consumer electronics, to create serviceable and robust connections.
19.2.2.2.2 Quick Disconnects (Blade or Spade Terminals)
These are designed for easy and fast single-wire connections that may need to be serviced or disconnected. They consist of a male tab and a female receptacle.
- Structure: The male part is a flat blade (often called a tab), and the female part is a rolled receptacle that slides over the blade, held in place by friction and spring tension. They are often covered with a plastic insulating sleeve.
- Usage: Commonly found in appliances, automotive wiring, and industrial machinery to connect wires to components like switches, speakers, and relays.
19.2.2.2.3 Ring & Fork (Spade) Terminals
These terminals are designed to connect a wire to a screw or stud.
- Structure:
- Ring Terminal: Has a closed, circular loop at the end. This is a very secure connection, as the terminal cannot be removed unless the screw is completely taken out.
- Fork (or Spade) Terminal: Has a U-shaped opening. This allows the terminal to be installed or removed by simply loosening the screw, which can be faster for installation and service.
- Usage: Used for grounding wires to a chassis or connecting power wires to bus bars, solenoids, and battery posts.
Wire seals must match wire OD (not just AWG). Loose seal = leak; oversize seal = torn during insertion.,
- Cavity plugs for all unused ways.
- TPA (Terminal Position Assurance) and CPA (Connector Position Assurance) are your friends—make them part of the inspection.
- Backshells/boots provide strain relief and 360° shield termination where needed.
- Target the IP level your product claims (e.g., IP67 submersion).
19.2.2.3 Special Crimping & Terminations
19.2.2.3.1 Auto Splice
"Autosplice" refers to a specific brand and a solderless crimping technology used for creating electrical connections in cable harnesses. The system is known for its speed, reliability, and the use of a continuous reel of spliceband material to create consistent, high-quality crimps.
The core of the technology is the Spliceband, a continuous reel of flat, serrated metal (typically tinned brass). An automated machine, called a crimper or applicator, feeds, cuts, and forms a single splice from this band around the wires being joined.
Machine Application:
The technology requires a specialized piece of equipment.
- The Machine: A bench-top crimping press is the main unit. This press provides the force needed for the crimp.
- The Applicator: This is the most critical part—a precision, interchangeable tooling head that is specific to the size of the splice being made. The applicator is responsible for the feed, cut, and form actions.
- The Spliceband: A continuous reel of the flat metal splicing material (usually tinned brass) is mounted on a holder and fed into the applicator.
Advantages
- High Speed and Efficiency: This is the primary benefit. An Autosplice machine can make thousands of splices per hour, making it ideal for high-volume, mass-production environments.
- Consistency and Reliability: The automated process eliminates human error. Every splice is created with the exact same material and crimp pressure, leading to highly
- consistent and reliable electrical connections.
- Versatility in Splicing: The system is excellent at joining multiple wires of different sizes together into a single, compact splice (often called a "star" connection).
Disadvantages
- High Initial Investment: The specialized crimping press and applicators are expensive. This makes the technology unsuitable for low-volume production, prototyping, or small repair shops.
- Lack of Environmental Sealing: A standard Autosplice connection is an open, uninsulated crimp. It is not waterproof and is vulnerable to moisture and corrosion. To be used in harsh environments, it requires a secondary process, such as applying heat-shrink tubing, which adds time and cost.
- Difficult Field Repairs: Autosplice connections are a factory solution. They cannot be easily repaired in the field, as they require the specialized machine to create. A damaged splice must typically be cut out and replaced using a different method, like a standard butt splice connector.
- Limited Functionality: The technology is specifically designed for splicing wires together. It cannot be used to create the pin and socket terminals needed to populate multi-pin connectors.
19.2.2.3.1 Ultrasonic-Welding Connection
Ultrasonic welding is a manufacturing technique that uses high-frequency vibrations to join materials together. In the cable harness industry, it's a highly reliable method for creating strong, solid-state welds between wires and terminals without melting the metal.
Applications in Cable Harnesses
Ultrasonic welding is primarily used for two key applications where a highly reliable connection is critical.
- Wire Splicing: It is an excellent method for splicing multiple wires together. It can easily join a large number of wires or wires of different sizes into a single, compact, and highly conductive joint. This is a common requirement in automotive harnesses where multiple circuits need to be connected to a single power or ground source.
- Wire-to-Terminal Termination: It is used to weld a wire or a group of wires directly to a terminal, often a ring terminal for a battery connection or a contact for a high-power connector. This creates a seamless connection with very low electrical resistance, which is ideal for high-current applications where minimizing heat buildup is crucial.
Advantages:
- Superior Electrical Performance: The process creates a seamless, void-free connection with extremely low electrical resistance. This minimizes heat buildup, making it ideal for high-current applications like battery cables and power distribution splices.
- Excellent Mechanical Strength: The resulting weld is incredibly strong and durable, often stronger than the original wires themselves. It provides excellent resistance to vibration and mechanical fatigue.
- High Reliability and Consistency: The process is controlled by precise parameters (pressure, time, and energy), which results in highly consistent and repeatable welds. This level of quality is critical in industries like automotive and aerospace.
- Joins Dissimilar Metals: Ultrasonic welding can effectively join dissimilar metals, such as copper to aluminum, which is very difficult to do with other methods.
Disadvantages:
- High Initial Investment: Ultrasonic welding equipment is expensive, representing a significant capital investment. This makes it best suited for high-volume manufacturing where the cost can be justified.
- Material and Size Limitations: The process works best with soft, non-ferrous metals like copper and aluminum. It is less effective on harder metals like steel. There are also practical limits to the size (total cross-sectional area) of the splice that can be effectively welded.
- Lack of Environmental Sealing: Like a standard crimp, an ultrasonic weld is an open, uninsulated connection. It requires a secondary process, such as adding heat-shrink tubing, to protect it from moisture and corrosion.
- Rigid Connection: The resulting weld nugget is a solid, rigid block. This lack of flexibility can be a disadvantage in applications that require the harness to be highly flexible at the splice point.
19.3.4 Keying & coding—how you ban mis-mates
Mechanically make the wrong mate impossible:
- Unique housings per voltage/system when practical (color + key).
- Polarized housings and key tabs that differ across variants.
- Clocking (circular): use different key positions (e.g., M12 A/D/X code; bayonet keys at different angles).
- Latch orientation: rotate housings so A cannot reach B’s latch.
- CPA: requires full insertion before latch can engage.
Visuals: color-code housings (e.g., RED = battery, BLACK = ground, BLUE = comms) and print port labels on the enclosure.
19.3.5 Pinout principles (so test and service are obvious)
- Numbering: always match the manufacturer’s cavity numbering; show pin-1 triangle on the drawing.
- Power first: put GND pins adjacent to +V (or multiple returns for high di/dt). Duplicate grounds for current share.
- Pairs stay pairs: keep twisted pairs on adjacent pins; maintain twist to the terminal.
- Shielding: design in a shell/chassis pin and specify 360° clamp where possible. If pigtail, <10 mm and to chassis near entry.
- Spare pins: mark “RESERVED”, leave unwired, and plug the cavities; don’t tie to GND unless the system design says so.
- Don’t swap sides: keep signal names consistent (J1-1 ↔ P1-1) unless the family requires mirroring—then call it out loudly.
19.3.6 Crimp & tool selection (no mystery crimps)
- Choose contacts by wire range (e.g., 20–22 AWG) and current rating; don’t jam 18 AWG into a 20–22 contact.
- Use the OEM applicator/dies; keep a cal log (18.2).
- Verify crimp height against the catalog; run pull tests per lot/type.
- For field crimping: use ratcheting tools with locators; no generic pliers.
Open-barrel (most harness work): conductor wings on conductor, insulation wings on insulation—both must wrap correctly.
19.3.7 Family-specific gotchas (save a trip back)
- Mini/Micro-fit & friends: pin pitch tight → derate current in high pin-count blocks; watch heat in the center.
- Deutsch/DT series: every cavity must have seal or plug; wedgelock fully seated or the TPA will not click—train eyes to see it.
- AMPSEAL/2.0: ensure wire OD vs seal match; wrong OD = leaks.
- M12: don’t mix A/B/D/X codes; they look similar but wire differently—print the code on labels/drawings.
- RJ45 in rough service: use industrial (M12-D/X) or sealed RJ with strain relief; tie the shield 360°—not with a long pigtail.
- USB-C: shell bond is critical; cable choice affects EMI & current—stick to certified assemblies unless you have a real HS test plan.
19.3.8 Anti-mis-mate toolkit (use several at once)
19.3.9 Inspection & test—what “good” looks like
- Terminal presence check: all required cavities populated; wedgelock engaged.
- Crimp quality: correct height, no broken strands, insulation support captured; bellmouth visible.
- Seal integrity: seals not nipped; plugs installed in unused cavities.
- Retention: sample terminal pull tests meet spec.
- Continuity/hipot: per drawing limits; shield continuity to chassis where specified.
- Label & keying: part numbers, codes (e.g., “M12-D”), and orientation arrows present and legible.
19.3.10 Documentation callouts (put it on the sheet)
- Connector detail with cavity numbering and key/polarization graphic.
- Contact PNs and tool/die ID per cavity type.
- Seal/plug PNs per cavity (wire OD range).
- Shield termination method (360° clamp vs pigtail length).
- CPA/TPA engagement as an inspection step.
- Pinout table (19.2) that matches test limits.
19.3.11 Common traps → smallest reliable fix
19.3.12 Pocket checklists
Selection
- Family fits environment/IP, current, cycles
- Contacts & plating matched to signal vs power
- Seals/backshells chosen; shield plan defined
Pinout & docs
- Pin numbering matches vendor; pin-1 marked
- Pairs adjacent; grounds near power; spare pins plugged
- Keying/coding printed (e.g., M12-X) on drawing/labels
Build & verify
- Correct tool/die; crimp height & pull tests OK
- TPA/CPA engaged; cavity plugs present
- Continuity/hipot passed; shield bond measured
Clear,
Bottomconsistent line:documentation choose a connector family that fitsties the environment,entire lockbuild inprocess contactstogether. By locking drawings, BOMs, and platingwire thattables matchinto one source of truth, manufacturers eliminate guesswork, accelerate production, and reduce the job,risk andof makecostly the wrong mate mechanically impossible with keying, coding, and CPA/TPA. Keep pairs together, ground smartly, and document pinouts so test can’t be confused. Do this, and your connectors will be boringly reliable—exactly what you want.