Product Overview

The Allen-Bradley 1746-OX8​ is an eight-point, individually isolated relay output module designed for the SLC 500 programmable controller platform. As a member of the Bulletin 1746 digital I/O family, the 1746-OX8​ provides eight Form A (normally open, SPST) electromechanical relay contacts, each electrically independent of every other point. That isolation is the defining characteristic of this module: unlike grouped relay cards such as the 1746-OW8, where several outputs share a common terminal, the 1746-OX8​ gives each channel its own pair of terminals with no shared field-side circuitry, so a single slot can switch different voltage levels, different AC phases or entirely separate grounding schemes without any risk of cross-coupling.Functionally, the 1746-OX8​ translates logic-level output bits from the SLC processor into physical contact closures. When the processor sets an output bit, the module energizes the corresponding relay coil from the backplane supply, and the associated contact pair closes to complete an externally supplied field circuit. Because the contacts are dry and galvanically separated, the module carries no field voltage of its own — the connected load determines what is switched — which makes it equally capable of handling 5–265V AC and 5–125V DC loads.The Allen-Bradley 1746-OX8​ occupies a single slot in any 1746 chassis, draws 85 mA at 5V DC and 90 mA at 24V DC from the backplane, and features front-panel LED status indication for each output plus a removable terminal block for fast wiring and module exchange. With 1500V AC isolation between field wiring and logic, heavy make/break contact ratings up to 30 A at 120V AC, and CSA certification for Class 1 Division 2 hazardous locations, the 1746-OX8​ is the module of choice wherever mixed-voltage, high-inrush or noise-sensitive loads must be controlled from an SLC 500 rack.

Technical Specifications

Main Features and Advantages

True point-to-point isolation: the single most valuable attribute of the 1746-OX8​ is that all eight outputs are individually isolated, both from the backplane and from each other. In practical terms this means you can switch 120V AC L1 on channel 0, 120V AC L2 on channel 1, a 24V DC circuit on channel 2 and a dry interlock contact from third-party equipment on channel 3 — all from one module — without creating a phase-to-phase short or a ground loop. With a grouped relay module that shares a common, that same arrangement would be dangerous. The 1500V AC dielectric withstand between adjacent points and between field wiring and logic also protects the SLC 500 backplane from field-side transients.Wide voltage flexibility: because the contacts are dry and rated for 5–265V AC and 5–125V DC, the 1746-OX8​ adapts to almost any control voltage found in an industrial panel. Maintenance teams value this because a single spare part can replace a failed card regardless of whether the load is AC or DC, which simplifies stocking for plants running mixed-voltage equipment.High inrush capability for inductive loads: motor contactor coils, solenoid banks and transformer-fed circuits draw surge currents many times their steady-state value, and solid-state outputs often cannot survive that. The 1746-OX8​ handles this comfortably with make ratings of 30 A at 120V AC and 15 A at 240V AC, backed by a 3600 VA make rating, so it reliably switches the kinds of inductive loads that would destroy a triac output. A maximum off-state leakage of 0 mA also means no phantom energizing of sensitive loads when the output is off.Serviceability and diagnostics: the 1746-OX8​ uses a removable terminal block, so field wiring stays intact when the module is replaced — a real advantage during a short outage window. Individual LEDs give immediate visual confirmation of each output state, and the module fits any slot of any 1746 chassis. Designed for Class 1 Division 2 hazardous locations and compliant with NEMA ICS 2-230 noise immunity, the 1746-OX8​ performs reliably in electrically harsh and regulated environments.