The Allen-Bradley 1756-TBNH is a heavy-duty 20-pin NEMA screw-clamp removable terminal block for ControlLogix I/O field installations. Genuine factory original units are in stock now with expedited worldwide delivery options. Safeguard your automation uptime and wiring integrity today.
The Allen-Bradley 1756-TBNH is a 20-position Removable Terminal Block (RTB) engineered specifically for the ControlLogix platform. It provides a modular, pluggable interface between external field devices (such as sensors, limit switches, and actuators) and the internal circuitry of ControlLogix digital, analog, or specialty I/O modules. By decoupling the field wiring bundle from the structural I/O chassis card, the RTB optimizes maintenance processes and maximizes operational uptime.
| Parameter | Specification |
|---|---|
| Model / Catalog No. | 1756-TBNH |
| Brand | Allen-Bradley / Rockwell Automation |
| Origin | USA |
| Weight | 0.9 kg (packaged block profile) |
| Dimensions | 3.5 x 13.0 x 14.5 cm |
| Module Type | Screw-Clamp Removable Terminal Block (RTB) |
| Total Positions | 20 Pins / Terminals |
| Conductor Wire Range | 22 AWG to 14 AWG ($0.32\text{ mm}^2$ to $2.1\text{ mm}^2$) Copper Only |
| Recommended Screw Torque | 1.36 Nm (12 lb-in) |
| Insulation Rating | Conductor temperature minimum rating of 90°C (194°F) |
| Discontinued Date | June 30, 2016 (Legacy hardware support item) |
The 1756-TBNH uses heavy-duty, NEMA-standard screw-clamp terminals housed within a rugged, finger-safe plastic enclosure. The mechanical clamping structure ensures reliable contact pressure, which helps prevent terminal loosening caused by physical industrial machine vibrations or local thermal expansion cycles.
Because it is a Removable Terminal Block, field technicians can disconnect an entire field wiring bundle from a failed or degraded I/O module instantly. The technician simply loosens the top and bottom mounting screws on the RTB housing, pulls the block away from the card faceplate, replaces the underlying I/O module slot asset, and reconnects the fully wired block. This completely eliminates the need to tag, label, desolder, or manually re-terminate up to 20 individual conductors during field replacements.
Q: Can the 1756-TBNH be paired with every ControlLogix I/O module?
A: No. The 1756-TBNH is a 20-pin block designed only for modules that feature a 20-pin front-panel interface layout (such as the 1756-IB16, 1756-OW16I, or 1756-IF8). High-density modules with 36 pins require a different part number, such as the 1756-TBCH.
Q: Is it permissible to land two separate wires into a single terminal point on this block?
A: Yes, provided the conductors are of the same size and type, and their combined solid cross-section does not exceed the maximum 14 AWG physical mechanical constraint of the clamping cage.
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