Allen-Bradley 1756-TBNH – 20-Pin Screw Terminal Block | ControlLogix Platform
The Allen-Bradley 1756-TBNH is a 20-pin screw-type wiring terminal block engineered for use with ControlLogix I/O modules. Designed by Rockwell Automation, this removable terminal block enables fast, reliable field-wiring connections without disturbing the I/O module itself — a critical advantage in live production environments where uptime is non-negotiable.
At Konmask.com, we supply the 1756-TBNH to procurement engineers and MRO teams worldwide, backed by traceability documentation and pre-shipment inspection. Whether you are commissioning a new panel or replacing a worn terminal block in an existing ControlLogix rack, this part ships ready to install.
Complete Technical Specifications
| Part Number | 1756-TBNH |
| Manufacturer | Allen-Bradley / Rockwell Automation |
| Platform | ControlLogix 1756 |
| Terminal Type | Screw-type (Non-spring) |
| Pin Count | 20 Pins |
| Wiring Style | Removable field-wiring terminal block |
| Compatible Modules | ControlLogix 1756 series I/O modules (20-pin footprint) |
| Mounting | Direct plug-in to compatible 1756 I/O module |
| Wire Gauge | 14–22 AWG (solid or stranded) |
| Insulation Rating | 300 V |
| Operating Temperature | 0 °C to +60 °C |
| Weight | Approx. 150 g |
| Certifications | UL Listed, CE Marked |
| Country of Origin | USA |
Proven Application Environments
- Discrete Manufacturing – Automotive assembly lines, machine tool control, and robotic cell integration using ControlLogix PLCs
- Process Industries – Oil & gas, chemical, and water treatment plants requiring robust I/O field wiring
- Power & Utilities – Substation automation and energy management systems built on the 1756 platform
- Food & Beverage – Hygienic production lines where quick terminal block removal speeds sanitation changeovers
- MRO & Spare Parts – Maintenance teams stocking critical spares to minimize unplanned downtime
Engineering Advantages
- Hot-swap wiring capability – Remove and re-wire the terminal block without powering down the I/O module, reducing maintenance windows
- Screw-clamp reliability – Positive mechanical retention of conductors resists vibration-induced loosening in industrial environments
- Keyed connector – Polarized design prevents mis-insertion, protecting both the module and field devices
- Wide wire gauge acceptance – Accommodates 14–22 AWG conductors, supporting both power and signal wiring in a single block
- Rockwell ecosystem compatibility – Fully validated within the ControlLogix 1756 architecture; no compatibility testing required
System Architecture & Signal Flow
The 1756-TBNH connects directly to the field-wiring side of compatible ControlLogix 1756 I/O modules. Field conductors are terminated at the screw-clamp contacts; the assembled block then plugs into the module’s 20-pin connector. Signal flow proceeds from field device → terminal block → I/O module → ControlLogix backplane → controller. The removable design means the field wiring harness remains intact during module replacement, eliminating re-termination errors and accelerating swap-out time from hours to minutes.
Sourcing & Quality Verification
- All 1756-TBNH units sourced through authorized distribution channels or verified surplus with full traceability
- Pre-shipment visual and dimensional inspection against Rockwell Automation published drawings
- Date code and lot documentation available upon request for regulated industries
- Packaging integrity check prior to dispatch — original Rockwell packaging preserved where available
- Counterfeit-risk mitigation: holographic labels, connector key geometry, and marking font verified against genuine samples
Procurement Process
- Confirm compatibility – Verify your I/O module part number accepts the 20-pin TBNH footprint (vs. TBNF spring-clamp variant)
- Submit RFQ or place order – Contact support@konmask.com or order directly on this page
- Lead time – In-stock units ship within 1–3 business days; expedited options available
- Documentation – Certificate of conformance, packing list, and commercial invoice provided with every shipment
- Payment – T/T, PayPal, and major credit cards accepted; Net 30 available for qualified accounts
Technical FAQ
Q: What is the difference between 1756-TBNH and 1756-TBNF?
A: Both are 20-pin terminal blocks for ControlLogix I/O modules. The TBNH uses screw-clamp termination; the TBNF uses spring-clamp (cage-clamp) termination. Screw-clamp (TBNH) is preferred where vibration is moderate and periodic re-torquing is acceptable. Spring-clamp (TBNF) offers tool-free insertion and superior vibration resistance.
Q: Is the 1756-TBNH compatible with all 1756 I/O modules?
A: No. The TBNH is designed for 1756 I/O modules with a 20-pin wiring connector. Modules with 36-pin connectors require the 1756-TBCH or equivalent. Always verify the module’s wiring terminal specification in the Rockwell Automation product selection guide before ordering.
Q: Can I reuse the terminal block after removing it from a module?
A: Yes. The 1756-TBNH is designed for repeated insertion and removal. Inspect screw torque and contact condition after each removal; replace if contact surfaces show wear or corrosion.
Q: What torque specification applies to the screw terminals?
A: Rockwell Automation specifies 0.5–0.6 N·m (4.4–5.3 lb·in) for the 1756-TBNH screw terminals. Always use a calibrated torque screwdriver during installation.
Q: Do you provide NAFTA/CO certificates for customs clearance?
A: Yes. Certificate of Origin documentation is available upon request for shipments requiring preferential tariff treatment.
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