Allen-Bradley 1756-TBSH ControlLogix 20-Pin Spring Terminal Block

Allen-Bradley 1756-TBSH ControlLogix 20-Pin Spring Terminal Block

The Allen-Bradley 1756-TBSH is a professional-grade 20-pin spring-clamp terminal block engineered for rapid field wiring of ControlLogix I/O modules. This removable terminal assembly eliminates the need for screwdrivers during installation and maintenance, dramatically reducing commissioning time while ensuring reliable electrical connections across demanding industrial applications.

Technical Specifications

• Catalog Number: 1756-TBSH
• Terminal Configuration: 20-pin spring-clamp design
• Wire Capacity: 22-14 AWG (0.33-2.08 mm²)
• Connection Method: Tool-free spring-clamp terminals
• Stripping Length: 9-10 mm (0.35-0.39 inches)
• Torque Requirements: None (spring-clamp mechanism)
• Operating Temperature: 0°C to 60°C (32°F to 140°F)
• Storage Temperature: -40°C to 85°C (-40°F to 185°F)
• Humidity Tolerance: 5% to 95% non-condensing
• Compatibility: ControlLogix 20-pin I/O modules (1756-IB16, 1756-OB16, etc.)
• Material: High-impact thermoplastic housing with copper alloy contacts

Key Advantages

Spring-clamp technology transforms installation workflows by enabling tool-free wire insertion—simply press the release button, insert the stripped conductor, and release for automatic clamping. This mechanism maintains consistent contact pressure across thermal cycling, preventing the loosening issues common with screw terminals in vibration-prone environments. The removable design allows pre-wiring at workbenches before module installation, then quick connection via the terminal block's plug-in interface, minimizing cabinet downtime during upgrades or replacements.

Wire gauge flexibility from 22 to 14 AWG accommodates both signal and power wiring within a single terminal block, reducing inventory complexity. Color-coded wire markers and numbered terminal positions eliminate wiring errors during initial installation and simplify troubleshooting during maintenance activities. The transparent release buttons provide visual confirmation of proper wire seating, a critical safety feature for high-reliability applications.

Industrial Applications

Automotive manufacturing plants deploy the 1756-TBSH across robotic welding cells where frequent reconfiguration demands rapid I/O module swapping without rewiring entire systems. Food and beverage facilities leverage the spring-clamp design in washdown areas where corrosion from cleaning chemicals would degrade screw terminals over time. Pharmaceutical production lines utilize these terminal blocks in cleanroom environments where minimizing particulate generation from tool use is essential for regulatory compliance.

Water treatment facilities benefit from the vibration resistance in pump control panels subjected to continuous mechanical stress. Packaging machinery integrators appreciate the time savings during machine builds, with spring terminals reducing wiring labor by up to 40% compared to screw-terminal alternatives. Mining operations in harsh environments rely on the terminal block's sealed construction to maintain connection integrity despite dust and moisture exposure.

Installation Best Practices

Strip wire insulation to the precise 9-10mm length indicated on the terminal block housing—excessive stripping exposes conductors to potential shorts, while insufficient stripping prevents proper contact engagement. Insert wires fully until resistance is felt, then verify the conductor is visible through the transparent release button window. For solid conductors, insertion is direct; for stranded wire, use ferrules to prevent strand separation and ensure optimal contact area.

When pre-wiring terminal blocks, organize wire bundles with cable ties before connecting to the I/O module to prevent strain on individual terminals. Label both ends of each wire using the terminal block's numbered positions as reference points. During module replacement, disconnect the entire terminal block assembly rather than individual wires to preserve wiring documentation and reduce reconnection errors.

Common Technical Questions

Q: Can I reuse wires after removing them from spring terminals?
A: Yes, spring terminals allow multiple insertion cycles without damaging conductors. However, inspect wire ends for deformation or oxidation before reuse, and re-strip if the conductor shows signs of damage from previous clamping.

Q: What is the maximum current rating per terminal?
A: Each terminal is rated for 1.5A continuous current at 60°C ambient temperature. This rating applies to the terminal block itself; actual current limits depend on the connected I/O module specifications and wire gauge used.

Q: Are ferrules required for stranded wire?
A: While not mandatory, ferrules are strongly recommended for stranded conductors to prevent strand breakage and ensure consistent contact pressure. Use uninsulated ferrules sized for your wire gauge, crimped according to manufacturer specifications.

Q: How do I verify proper wire insertion?
A: Gently tug each wire after insertion—properly seated conductors will not pull free with moderate force. Additionally, the wire should be visible through the transparent release button, and the stripped portion should not extend beyond the terminal housing.

Compatible ControlLogix Products

Warranty & Technical Support

Each 1756-TBSH terminal block is backed by a comprehensive 12-month manufacturer warranty covering defects in materials and workmanship. Our technical support team provides wiring diagrams, installation guidance, and troubleshooting assistance to ensure successful integration into your ControlLogix system.

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