AB Allen-Bradley 1756-TBN 20-Pin Screw-Type Terminal Block

Product Summary

The Allen-Bradley 1756-TBN is a 20-Pin Screw-Type Terminal Block manufactured by Rockwell Automation for use with ControlLogix I/O modules. It provides a removable wiring interface that allows field wiring to be disconnected from the module without disturbing the terminal connections, simplifying module replacement and maintenance. The screw-clamp design accepts a wide range of wire gauges for flexible industrial installation.

Core Specifications

• Model Number: 1756-TBN
• Type: 20-Pin Screw-Type Removable Terminal Block
• Positions: 20 pin
• Wire Range (Single): 0.33–2.1 mm² (22–14 AWG) solid or stranded copper
• Wire Range (Double): 0.33–1.3 mm² (22–16 AWG) solid or stranded copper
• Wire Insulation Max: 1.2 mm (3/64 in.)
• Wire Temperature Rating: 105°C (221°F) minimum
• Torque Specification: 0.8 N·m (7 lb·in)
• Mounting: Snaps onto ControlLogix I/O module front connector
• Weight: 0.136 kg
• Manufacturer: Allen-Bradley by Rockwell Automation

Electrical & Functional Characteristics

• Connection Type: Screw clamp (NEMA style) — field wires secured via terminal screws
• Removability: Terminal block detaches from module as a complete unit, allowing module swap without rewiring
• Keying: Mechanically keyed to prevent incorrect insertion orientation
• Contact Material: Tin-plated copper for reliable conductivity and corrosion resistance
• Wire Category: 1 — on signal ports

System Integration & Compatibility

• Compatible Modules: All 20-pin ControlLogix I/O modules including 1756-IA16, 1756-IB16, 1756-IF8, 1756-IR6I, 1756-IT6I, 1756-OA16, 1756-OB16, 1756-OF8
• Platform: ControlLogix 1756 chassis
• Related Terminal Blocks:
  • 1756-TBNH — 20-pin NEMA screw clamp (same form factor, alternate catalog)
  • 1756-TBCH — 36-pin cage-clamp terminal block
  • 1756-TBS6H — 36-pin spring-clamp terminal block
  • 1756-TBSH — 20-pin spring-clamp terminal block

Environmental & Operational Limits

• 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: 5% to 95% RH, non-condensing
• Approvals: GOST R certified, Marine (ABS, BVS, DNV, GL, KRS, LR), ROSTECHNADZOR

Industrial Applications

Widely used across all ControlLogix installations in manufacturing, process control, oil & gas, water treatment, and material handling where removable terminal blocks enable quick module replacement and minimize downtime during maintenance.

Frequently Asked Questions

What is the 1756-TBN used for?

It is a 20-pin screw-type removable terminal block that provides the field wiring interface for ControlLogix I/O modules. The block detaches from the module as a unit, allowing module replacement without disconnecting individual wires.

What wire size does the 1756-TBN accept?

Single wire: 0.33–2.1 mm² (22–14 AWG). Double wire: 0.33–1.3 mm² (22–16 AWG). Wire insulation must not exceed 1.2 mm diameter.

What is the torque specification?

Torque terminal screws to 0.8 N·m (7 lb·in) for secure, reliable connections.

What is the difference between 1756-TBN and 1756-TBNH?

The 1756-TBN and 1756-TBNH are functionally identical 20-pin NEMA screw-clamp terminal blocks with the same form factor and compatibility. The catalog number suffix difference reflects packaging or regional variations.

What are the related part numbers?

• 1756-TBN — 20-pin screw-clamp terminal block (this part)
• 1756-TBNH — 20-pin NEMA screw-clamp terminal block
• 1756-TBCH — 36-pin cage-clamp terminal block
• 1756-TBS6H — 36-pin spring-clamp terminal block
• 1756-TBSH — 20-pin spring-clamp terminal block