In any electrical system, from complex industrial control panels to simple power distribution units, the reliability of every connection point is paramount. Terminal blocks provide a secure and organized way to join wires, and among the most common types used, especially where space is a premium, are UKK series blocks. But with various specifications and configurations available, knowing how to select the right UKK terminal block is crucial for ensuring operational safety, efficiency, and long-term performance.
Choosing incorrectly can lead to overheating, connection failures, difficult maintenance, or even safety hazards. This guide will walk you through the essential factors to consider, helping you confidently select the optimal UKK terminal block for your specific application in 2025 and beyond.
Understanding UKK Terminal Blocks: Basics and Benefits
Before diving into selection criteria, let’s clarify what UKK terminal blocks typically represent and why they are frequently chosen.
What is a UKK Terminal Block?
While “UKK” can sometimes refer to a specific manufacturer series, in the broader industry context, it most commonly denotes double-level (or double-deck) DIN rail mounted terminal blocks. This design stacks two isolated termination points vertically within a single block housing. They often utilize screw clamp connection technology, though other types like spring-cage might exist under similar nomenclature depending on the brand. Always verify specifics with manufacturer datasheets.
Key Advantages
The primary benefits of using UKK-style double-level blocks include:
- Space Saving: They significantly increase wiring density on the DIN rail, effectively halving the required mounting space compared to single-level blocks.
- Organization: Grouping related circuits (e.g., positive and negative pairs, sensor inputs) vertically can simplify wiring layout and troubleshooting.
- Säkra anslutningar: Like other high-quality terminal blocks, they provide reliable mechanical and electrical connections when properly installed.
Common Connection Technologies
The most prevalent connection type for UKK blocks is the screw clamp, valued for its secure grip on a wide range of wire sizes and types. Some manufacturers might offer variations using spring-cage or push-in technology under similar series names, offering faster wiring possibilities.
Critical Factors for Selecting Your UKK Terminal Block
Making the right choice involves carefully evaluating several technical parameters against your application requirements. Here’s a breakdown of the critical factors:
Electrical Ratings: The Non-Negotiables
These are fundamental to safety and performance.
- Spänningsklassning: The block must have a voltage rating (AC/DC) equal to or greater than the maximum system voltage it will encounter. Consider both phase-to-phase and phase-to-ground voltages.
- Nuvarande betyg: Select a block with a current rating that meets or exceeds the maximum continuous current the circuit will carry. Remember to account for potential derating factors based on ambient temperature, grouping, and wire size used.
Wire Compatibility: Size and Type
The terminal block must securely accommodate the wires being used.
- Wire Gauge Range (AWG / mm²): Check the manufacturer’s specifications for the minimum and maximum wire sizes the block is designed for. Using the wrong size can lead to poor connections or damage.
- Conductor Type: Verify compatibility with solid, stranded, or fine-stranded wires. Fine-stranded wires often require ferrules for reliable termination in screw clamps – ensure the block accommodates ferruled wires if needed.
Physical and Environmental Considerations
Where and how the block is used matters significantly.
- Number of Levels: UKK typically implies double-level, maximizing density. Confirm this meets your needs versus single-level blocks if space isn’t the primary constraint.
- Monteringstyp: Most UKK blocks are designed for standard Montering på DIN-skena (e.g., 35mm TH35 rail). Ensure compatibility with your existing rail system.
- Operating Temperature Range: Choose a block rated for the ambient temperature range within the enclosure or operating environment.
- Material and Flammability Rating: Look for high-quality insulating materials (like Polyamide PA 6.6) with appropriate flammability ratings (e.g., UL 94 V-0) for safety.
- IP Rating / Environmental Protection: While the block itself often relies on the enclosure for protection, consider if special sealing or material resistance (e.g., against chemicals) is needed in harsh environments.
Application-Specific Needs
Consider the function the block will serve:
- Control Circuits vs. Power Distribution: Power circuits generally require higher current ratings and larger wire acceptance.
- Signal Density: Double-level blocks excel where many connections are needed in a small space.
- Test/Disconnect: Do you need built-in test sockets or disconnect levers for troubleshooting? Specialized UKK variants might exist.
Standarder och certifieringar
Ensure the blocks meet relevant safety and quality standards for your region and application. Look for markings like UL, CSA, CE, and RoHS compliance. Using certified components is crucial for safety and regulatory acceptance.
Exploring Different UKK Terminal Block Types
While the double-level feed-through block is standard, related types often share the UKK designation or are used alongside them:
Standard Feed-Through Blocks
The most common type, providing two independent pass-through connections stacked vertically.
Grounding (PE) Blocks
Similar in form but designed to connect protective earth wires directly to the DIN rail (which should be properly grounded). Often colored green/yellow.
Disconnect or Fuse Blocks
Some UKK-style blocks incorporate knife-switches, plugs, or fuse holders for circuit isolation or protection within the same profile.
Sensor/Actuator Blocks
Specialized multi-conductor blocks, sometimes following the UKK form factor, designed for efficiently connecting sensors with multiple wires (power, ground, signal).
Essential UKK Terminal Block Accessories
Accessories complete the installation and enhance usability:
End Plates and Partition Plates
End plates cover the open side of the last block in a row. Partition plates visually or electrically separate groups of blocks.
Marking Tags / Labels
Crucial for identifying circuits, simplifying assembly, troubleshooting, and maintenance. Various marking systems exist.
Jumpers / Bridges
Used to connect adjacent or alternate terminal points within the blocks, common for distributing power or common signals. Available in various pole counts.
Covers and Shields
Optional protective covers can offer additional protection against accidental contact or debris.
Common Mistakes to Avoid When Choosing UKK Blocks
Being aware of common errors can save time and prevent problems:
Underspecifying Voltage/Current Ratings
Selecting blocks rated below the actual operating conditions is a major safety risk. Always use a margin of safety.
Ignoring Wire Type Compatibility
Assuming a block suitable for solid wire works equally well with fine-stranded wire without a ferrule can lead to unreliable connections.
Forgetting Necessary Accessories
Failing to order end plates, markers, or jumpers during the initial selection can delay assembly.
Förbiseende av miljöfaktorer
Using standard blocks in environments with high vibration, extreme temperatures, or corrosive elements without appropriate ratings can lead to premature failure.
Quick Checklist for UKK Terminal Block Selection
Before finalizing your choice, run through this checklist:
- [ ] Correct Voltage Rating? (≥ System Max)
- [ ] Correct Current Rating? (≥ Circuit Max, consider derating)
- [ ] Correct Wire Gauge Range? (Min/Max AWG or mm²)
- [ ] Compatible with Wire Type? (Solid, Stranded, Fine Stranded +/- Ferrule)
- [ ] Suitable Mounting? (DIN Rail Type)
- [ ] Double-Level Needed? (Space saving)
- [ ] Environmental Ratings Match? (Temp, Materials)
- [ ] Required Certifications Met? (UL, CE, etc.)
- [ ] Necessary Accessories Included? (End Plates, Markers, Jumpers)
Featured UKK Terminal Blocks from VIOX ELECTRIC
Applying the selection principles discussed earlier requires looking at specific manufacturer specifications. To illustrate the range of options available and the type of data you’ll encounter, here are details for several UKK series distribution terminal blocks currently offered by VIOX ELECTRIC (www.viox.com), designed to meet various power distribution needs:
| Product Name (Model) | Input/Output Lines Configuration | External Dimensions (W x L x H) mm | Wiring Area (mm²) |
|---|---|---|---|
| UKK80A | 1 Input / 6 Output | 30 x 69 x 46 | Input: 1 x (6-16mm²) Output: 4 x (2.5-6mm²), 2 x (2.5-16mm²) |
| UKK125A | 1 Input / 6 Output | 29 x 70 x 46 | Input (Choose one): 1 x (6-16mm²) OR 1 x (10-35mm²) Output: 6 x (2.5-16mm²) |
| UKK160A | 1 Input / 6 Output | 29 x 70 x 46 | Input (Choose one): 1 x (6-16mm²) OR 1 x (10-70mm²) Output: 6 x (2.5-16mm²) |
| UKK250A | 1 Input / 11 Output | 50 x 96 x 49 | Input: 1 x (35-120mm²) Output: 2 x (6-35mm²), 5 x (2.5-16mm²), 4 x (2.5-10mm²) |
| UKK400A | 1 Input / 11 Output | 50 x 96 x 49 | Input: 1 x (95-185mm²) Output: 2 x (6-35mm²), 5 x (2.5-16mm²), 4 x (2.5-10mm²) |
| UKK500A | 1 Input / 11 Output | 50 x 96 x 49 | Input: 1 x (3*15mm – 8*24mm range)* Output: 2 x (6-35mm²), 5 x (2.5-16mm²), 4 x (2.5-10mm²) *(Note: Input spec likely refers to specific conductor/busbar dimensions)* |
Data sourced from VIOX ELECTRIC specifications.
This table highlights key parameters like input/output configurations, dimensions, and compatible wire sizes (wiring areas) which are crucial for selection, as discussed in this guide. Models like the UKK125A and UKK160A offer flexibility with optional input sizes. The larger UKK250A, UKK400A, and UKK500A models cater to higher current distribution needs with multiple output terminals for various wire gauges.
For complete specifications, datasheets, and to explore the full range of terminal blocks and other electrical components, please visit VIOX ELECTRIC at www.viox.com.
Conclusion: Ensuring Safe and Reliable Connections
Selecting the appropriate UKK terminal block goes beyond just finding one that fits. It’s a critical step in designing and building safe, reliable, and maintainable electrical systems. By carefully considering the electrical ratings, wire compatibility, physical constraints, environmental conditions, and necessary accessories outlined in this guide, and by reviewing specific product data like the examples provided by VIOX ELECTRIC, you can confidently select the UKK terminal block that precisely meets your application’s demands. Taking the time to choose correctly contributes significantly to the overall quality and longevity of your electrical installation.
For assistance in selecting the ideal UKK terminal block solution for your project, browse our comprehensive catalog or contact our technical support team today.
