| Contact plating | Tin over copper alloy | Usually suitable for low-cost, low-to-moderate cycle connections; common operating range is approximately −40°C to +105°C, depending on the connector system. | Power distribution, automotive harnesses, appliances, and equipment where connections are rarely mated and unmated. | Low cost, good solderability, and suitable electrical conductivity for many power applications. | More vulnerable to fretting corrosion and oxidation than noble-metal finishes. Use sufficient normal force and verify contact resistance after vibration and environmental testing. |
| Contact plating | Nickel underplate | Common underlayer thickness is approximately 1–3 µm; actual values vary by construction and specification. | As a diffusion barrier beneath gold, tin, or other contact finishes. | Improves wear resistance, limits copper migration, and supports thermal and environmental durability. | Nickel is not normally selected as the sole mating-contact finish for low-force signal contacts because its higher hardness and oxide behavior can increase contact resistance. |
| Contact plating | Gold over nickel | Typical contact-gold thickness ranges from about 0.1–1.0 µm for many commercial designs; thicker finishes are used for higher durability. | Low-level signals, instrumentation, data interfaces, and applications requiring stable contact resistance. | Excellent resistance to oxidation and corrosion; performs well with low contact forces and small signal voltages. | Higher cost than tin. Thin gold can wear through under repeated mating, so specify thickness, hardness, underplate, and mating-cycle requirement together. |
| Contact plating | Hard gold alloy over nickel | Often selected for hundreds to several thousand mating cycles, but the exact cycle rating must come from the connector qualification test. | Test equipment, modular systems, serviceable instrumentation, and frequently disconnected cable assemblies. | Better wear resistance than soft or pure gold while maintaining good corrosion performance. | Gold-alloy composition and hardness affect performance. Confirm that the mating connector uses a compatible contact finish and that the cycle rating includes the intended cable geometry. |
| Contact plating | Silver | High electrical conductivity; commonly used in power contacts, with temperature capability determined by the base material and connector design. | High-current power connections and applications where low bulk resistance is important. | Very low electrical resistivity and good current-carrying capability. | Can tarnish in sulfur-containing or contaminated atmospheres. It is generally less suitable than gold for very low-level signals unless the contact system is specifically designed for it. |
| Base material | Copper alloy | High conductivity with good spring properties when the alloy and temper are correctly selected. | Most signal and power contact systems. | Good balance of conductivity, elasticity, manufacturability, and cost. | Requires a suitable plating system to prevent oxidation, corrosion, and copper diffusion at the mating interface. |
| Base material | Phosphor bronze | Good spring retention over repeated insertion and thermal exposure; conductivity is lower than pure copper. | Signal contacts, board connectors, and cable connectors requiring reliable contact force. | Good fatigue resistance, strength, and resistance to stress relaxation. | Higher electrical resistance than high-conductivity copper alloys; verify current rise and temperature at the intended load. |
| Base material | Beryllium copper | High spring performance and strong resistance to contact-force loss when properly processed. | High-cycle contacts, compact connectors, and applications with demanding contact-force requirements. | Excellent elasticity, fatigue resistance, and resistance to stress relaxation. | Material handling and manufacturing must control beryllium exposure. Confirm compliance, processing controls, and plating coverage. |
| Insulator material | Polyamide or nylon | Typical continuous-use capability is approximately −40°C to +105°C, with grades varying by formulation. | General-purpose cable connectors, consumer equipment, and moderate-temperature harnesses. | Good toughness, impact resistance, and cost efficiency. | Can absorb moisture, which may affect dimensions, insulation resistance, and mechanical stability. Confirm flammability and moisture requirements. |
| Insulator material | Polybutylene terephthalate (PBT) | Common continuous-use range is approximately −40°C to +125°C, depending on grade and design. | Automotive, industrial, and moderately elevated-temperature connector housings. | Good dimensional stability, chemical resistance, and electrical insulation properties. | Verify resistance to glycol, oils, cleaning fluids, humidity, and long-term heat aging. |
| Insulator material | Polyetheretherketone (PEEK) | Many grades support continuous use near +250°C, with short-term limits potentially higher; consult the material grade specification. | Aerospace, chemical processing, high-temperature instrumentation, and harsh industrial environments. | Excellent heat resistance, chemical resistance, dimensional stability, and low outgassing compared with many commodity plastics. | Higher material and processing cost. Check dielectric properties, sterilization exposure, assembly temperature, and long-term mechanical loading. |
| Temperature selection | Standard industrial | Approximately −40°C to +85°C or −40°C to +105°C for many connector families. | Indoor equipment, factory automation, control panels, and general-purpose electronics. | Broad availability and balanced cost-to-performance ratio. | Calculate the combined effect of ambient temperature, current-induced heating, enclosure temperature, and cable bundle derating. |
| Temperature selection | High-temperature industrial or automotive | Approximately −40°C to +125°C; some qualified systems support +150°C or higher. | Engine compartments, motor drives, outdoor equipment, and industrial machinery near heat sources. | Improved resistance to thermal aging and insulation degradation. | Temperature rating is not always valid at maximum current. Confirm derating curves, seal rating, contact force retention, and thermal cycling results. |
| Temperature selection | Low-temperature service | Common ratings extend to −55°C; specialized systems may reach approximately −65°C or lower. | Outdoor electronics, aerospace systems, cold-chain equipment, and high-altitude installations. | Maintains mechanical and electrical function in cold environments when correctly specified. | Check impact strength, seal flexibility, lubricant viscosity, cable jacket stiffness, and contraction-related contact force changes. |
| Mating durability | Low-cycle connector | Typically up to approximately 10–50 mating cycles, depending on construction. | Permanent installations, field wiring, and connectors normally serviced only during maintenance. | Usually provides the lowest cost and simplest construction. | Do not pay for high-cycle plating when the connector will remain mated. Prioritize sealing, locking, strain relief, and installation reliability. |
| Mating durability | General service connector | Typically approximately 100–500 mating cycles. | Industrial equipment, replaceable modules, test fixtures, and maintenance-accessible cable assemblies. | Balances serviceability, durability, and cost. | Cycle rating can change with contact plating, insertion speed, misalignment, contamination, and side-load from the cable. |
| Mating durability | High-cycle connector | Often rated from approximately 1,000 to 10,000 cycles; specialized systems may be rated higher. | Test equipment, robotics, automated production, medical equipment, and frequently exchanged modules. | Designed for repeated mechanical engagement with controlled wear and contact-force retention. | Verify the complete connector and cable assembly. Use the specified mating procedure and inspect contact resistance after cycling. |
| EMI shielding | Unshielded plastic housing | No intentional cable shield termination; EMI performance depends mainly on cable routing, grounding, and system enclosure. | Low-noise environments and non-sensitive low-speed signals. | Lightweight, low cost, and simple termination. | Not recommended where radiated emissions, susceptibility, or high-speed common-mode noise is a major concern. |
| EMI shielding | 360-degree shield termination | The cable shield is bonded around the connector circumference rather than using a long pigtail. | High-speed data, industrial Ethernet, motor-control feedback, and sensitive analog systems. | Reduces shield inductance and generally provides better high-frequency noise control than a long drain-wire pigtail. | Shield continuity must include the connector shell, backshell, panel, and equipment chassis. A shield that terminates only to signal ground may create unwanted current paths. |
| EMI shielding | Metal shell with conductive gasket | Provides a continuous conductive barrier when mating surfaces, seams, and cable shields are properly bonded. | High-EMI industrial environments, aerospace equipment, radio systems, and applications with strict emissions limits. | Improves shielding effectiveness and can support enclosure-level EMC control. | Paint, anodizing, corrosion, loose hardware, and discontinuous gasket compression can interrupt the RF bonding path. Specify surface preparation and bonding resistance. |
| Ingress protection | Unsealed connector | Typically intended for protected indoor environments; no reliable water or dust rating should be assumed without a stated IP classification. | Control cabinets, laboratory equipment, and clean indoor installations. | Lower cost and easier assembly. | Protect from condensation, spray, dust, and cable washdown. Connector IP performance usually applies only when fully mated and correctly assembled. |
| Ingress protection | Sealed connector | Common target ratings include IP65, IP67, or IP68; the exact test depth and duration must be specified. | Outdoor equipment, mobile machinery, washdown areas, and exposed industrial systems. | Improves resistance to dust and water ingress when properly mated and strain-relieved. | Check cable diameter range, seal compression, venting, chemical compatibility, pressure cycling, and whether the rating applies after mating cycles. |
| Electrical performance | Low-current signal contact | Prioritize stable low contact resistance and low fretting sensitivity; current and voltage limits are connector-specific. | Sensors, measurement circuits, communication interfaces, and instrumentation. | Supports signal integrity and reliable detection of small voltages or currents. | Evaluate contact resistance stability, insulation resistance, crosstalk, shielding, vibration, and contamination rather than relying only on nominal current rating. |
| Electrical performance | Power contact | Current ratings commonly range from a few amperes to hundreds of amperes, depending on contact size, conductor size, housing, ambient temperature, and allowable temperature rise. | Power supplies, battery systems, motors, industrial controls, and high-current cable assemblies. | Designed to carry higher current with controlled heat generation. | Use the manufacturer’s derating curve. Check conductor cross-section, crimp quality, parallel circuits, temperature rise, short-circuit withstand, and touch safety. |
