Choosing The Ideal Pitch For Your Push In Terminal Block
To select the correct pitch for a push in terminal block, you must balance electrical insulation requirements with physical space constraints. The pitch, or the center-to-center distance between adjacent poles, is primarily determined by the system voltage and the required creepage and clearance distances. Standard industrial pitches typically range from 2.5mm for compact signal interfaces to 7.5mm or more for high-voltage power applications.
Importance of Pitch in Electrical Design
Selecting the right spacing is critical for both safety and functionality. In modern control cabinets, space is a premium commodity. Using a push fit terminal block with a smaller pitch allows for higher density, but reducing the distance too much can lead to electrical arcing if the voltage exceeds the insulation capacity of the air or the housing material.
| Spacing (mm) | Voltage Rating (V) | Primary Use Case |
| 2.50 / 3.50 | 150 - 300 | Signal processing and sensors |
| 5.00 / 5.08 | 300 - 600 | General industrial control |
| 7.50 / 7.62 | 600 - 1000 | Power supplies and high-load circuits |
Key Factors for Selection
Voltage and Creepage Distances
The higher the operating voltage, the larger the pitch required. Engineers must follow standards such as IEC 60947-7-1 to ensure that the push fit din rail terminals provide enough distance to prevent surface tracking. For example, a 5.0mm pitch is often the "sweet spot" for 300V-600V industrial environments.
Wire Gauge and Current Capacity
Pitch is often dictated by the physical size of the wire. A larger pitch accommodates thicker insulation and higher current ratings. When using push in din rail terminal blocks, ensure the pitch allows for the maximum outer diameter of your intended conductors, especially when using ferrules.
Streamlining Installation on Mounting Rails
For high-density wiring, push in din rail terminal blocks offer significant time savings. By matching the pitch to your specific PLC or I/O module requirements, you can maintain a clean, organized layout that simplifies maintenance and troubleshooting for field technicians.
