Circular connectors
Signal and power transmission in a compact, robust design
Basics & Connector Types
Essentially, connectors establish a detachable connection between wires, cables, circuit boards, and devices. Electrical wires and signal lines are thus reliably connected. Depending on the application, different contact technologies may be used. In addition to the classic connector, cut-to-length connections, crimp connections, screw connections, solder and spring-loaded connections, as well as IDC connections or push-in connections, are also in use.
Criteria such as number of pins, pitch, locking mechanism, and coding are decisive for selection. They determine how compact, mis-insertion-proof, and resilient a connection will be in later use.
Rectangular connectors
For junction boxes, control cabinets, and modular industrial applications
Coaxial connectors (HF)
Defined impedances for high-frequency signal and data transmission
PCB connectors
Connect circuit boards in electronic devices, e.g., wire-to-board.
Miniature connectors
High performance in a small space.
Power connectors
Carry high currents and voltages, e.g., CEE connectors, Schuko.
Data connectors
For reliable data transmission, e.g., RJ45 connectors, USB, HDMI.
AV connectors
For audio-video connections with jack plugs, RCA, or XLR.
What to look for when buying connectors?
Not every connector is suitable for every application. The key is making a tailored selection that takes into account both the electrical requirements as well as environmental conditions and assembly processes.
Mechanics & Service Life
Mating cycles, vibration resistance, strain relief, locking mechanism (e.g., screw, bayonet, or push-pull)
Electronic Requirements
Current / voltage and signal type
Environmental Conditions
Temperature range, humidity, dust, chemicals, UV exposure
Shielding & EMC
Especially important for data and signal interfaces
Size & Miniaturization
Space requirements, pitch, installation situation, field handling
Material Selection
Lightweight or robust housing materials (e.g., plastic/metal), corrosion protection, contact material and coating
Modularity
Modular systems facilitate adaptations, service, and expansions (e.g., mixed inserts for signal, data, and power)
Safety & Standards
Comply with current guidelines and legal regulations
Tip
It is worth taking a systematic approach to connectors: plug, receptacle, cable, housing, seal, and strain relief must all fit together. Only then will the connection remain permanently stable under load. Connectors for Power Supply
Where energy flows, reliable components are needed: Connectors for power supply must safely transmit electrical energy. Durability and protection against external influences are essential. Also crucial are standard-compliant design, robust materials, and reliable contact—so that machines, systems, and devices are well-supplied even under load.
Depending on the application, various solutions are available : from compact device connectors for equipment connections to industrial-grade CEE connectors and cable connectors for flexible installations. For photovoltaic systems or agriculture, UV and weather resistance as well as appropriate protection ratings also play a central role.
Signal and Data Transmission
To ensure that controllers, sensors and systems work together precisely, connectors are needed that transmit signals and data without interference. In this area, the most important factors are consistent contact quality, proper shielding, and the appropriate design for the required data rate.
In high-frequency applications, for example, coaxial connectors demonstrate their strengths because they support defined impedances and transmit signals with exceptional reliability.
Power connectors & power applications
Power connectors are used wherever high currents, voltages, or load cycling must be safely managed, such as in drive and motor technology, in control cabinets, in power distribution, in charging infrastructure, or in photovoltaic and energy storage applications.
What matters most in power applications:
Contact Technology & Environmental Resistance
High‑quality contacts reduce contact resistance and heat generation; corrosion protection, seals, and appropriate protection ratings ensure durability in harsh conditions.
Secure Locking
Against accidental disconnection, especially during vibration or tensile stress.
Touch Protection
To protect users and comply with safety requirements.
Cable Cross‑Sections & Assembly
Appropriate crimp/screw contacts, clear assembly processes, reliable strain relief.
Connectors for harsh environments
Dust, moisture, cleaning agents, UV radiation, vibrations, or extreme temperatures: In many applications, environmental resistance determines failure risks and maintenance intervals.
Pay particular attention to the following:
Dense Connector Assemblies
With appropriate protection ratings
Robust Housing Materials
Metal or high-quality plastics, corrosion-resistant surfaces
Vibration‑Resistant Locking Mechanisms
e.g., bayonet, screw, push‑pull depending on the application
Kink Protection & Strain Relief
For moving cables
Chemical & UV Resistance
For outdoor areas and harsh environments
Our tip
In our online shop, you can easily filter by IP protection classes, locking mechanisms, and housing material. This way, you can quickly find the right connector for your requirements. Normen & Schutzarten
The IP protection rating describes how well a product is protected against foreign objects (e.g., contact, dirt, dust) and moisture/water. IP stands for International Protection or Ingress Protection. The rating consists of two digits: the first digit (0–6) for protection against contact and dust, the second digit (0–8) for protection against water and moisture.
Read more in our blog post.Common IP protection ratings – and what they are typically used for
IP40
- Dust protection: Foreign objects > 1 mm
- Water protection: No protection
- Typical application: Dry indoor areas
IP54/55
- Dust protection: Dust-protected
- Water protection: Splash water / jet (low pressure)
- Typical application: Weatherproof, rainproof
IP65
- Dust protection: Dust-tight
- Water protection: Water jets
- Typical application: Outdoor installations
IP67
- Dust protection: Dust-tight
- Water protection: Temporary submersion
- Typical application: Damp / wet environments
IP68
- Dust protection: Dust-tight
- Water protection: Continuous submersion
- Typical application: Continuous underwater applications
| Protection rating | Dust protection | Water protection | Typical application | Protection rating |
|---|---|---|---|---|
| IP40 | Foreign objects > 1 mm | No protection | Dry indoor areas | |
| IP54/55 | Dust-protected | Splash water / jet (low pressure) | Weatherproof, rainproof | |
| IP65 | Dust-tight | Water jets | Outdoor installations | |
| IP67 | Dust-tight | Temporary submersion | Damp / wet environments | |
| IP68 | Dust-tight | Continuous submersion | Continuous underwater applications | |
Practical tip
Always select the protection rating appropriate for the actual environment—including cleaning (e.g., high-pressure), condensation, direct weather exposure, and mounting position. Also important: The IK protection rating (impact resistance) per IEC 62262 is relevant for outdoor installations, factory halls, or installations at risk of vandalism. Assembly, Accessories & Tools
A good connector is more than just a plug and socket. Only with the right accessories and clean workmanship can a durable, reliable connection be created.
Key components:
Contacts (Crimp, Screw, IDC)
Suitable for cross‑section and material
Seals, Grommets, Housings and Caps
For protection and strain relief, adapters
Cables & Wires
To ensure secure connections
Cable Glands and Kink Protection
For mechanical stability
Tools
Crimping pliers, wire strippers, testing and release tools, soldering stations, crimping tools
Marking & Coding
For serviceability and prevention of incorrect connections
Tip
Those who frequently assemble cables benefit from repeatable processes: defined stripping lengths, matching crimp dies, and a documented quality check (e.g., tensile test) significantly increase process reliability. 
Solutions from our partners
Many applications can be implemented faster and more reliably when components are considered as a system: coordinated connector families, compatible accessories, and clear specifications simplify selection, installation, and operation.
Bürklin: Services from us for you
Often, the right combination of design, material, and protection rating determines the reliability of your application. With our services, we support you from the initial selection through to long-term supply assurance.
Technical support
Together, we identify individually tailored connector solutions
Simple ordering process
With the convenient filtering in the Bürklin online shop, you can find your desired product with just a few clicks.
Ready for use quickly
We guarantee immediate delivery for in-stock items.
Further information & Knowledge Hub
Want to dive deeper? In our Knowledge Hub, you’ll find helpful content on the selection, processing, and application of connectors, including foundational articles, practical tips, and thematically relevant product categories.
Frequently asked questions about connectors
Models with an appropriate IP rating, UV-resistant materials, corrosion-protected contacts, and secure locking.
Rated current/voltage, temperature rise (contact resistance), secure locking, protection against accidental contact, as well as appropriate cable cross-sections and proper assembly.
Clearly visible coding reduces misconnections, and locking prevents unintentional disconnection—both enhance process and operational safety.
That depends on the quantity, assembly process, and requirements: Crimping is often reproducible and vibration-resistant, screw terminals are service-friendly, and IDC is fast to process, provided they are correctly specified.