Scully 22485 Green Thermistor Plug & Cable Assembly (4 J-Slot)

The Scully 22485 thermistor plug is a green-coded plug and cable assembly built for tank truck overfill prevention circuits, providing the field-side connection between a vehicle-mounted socket and a Scully loading rack control monitor such as the Intellitrol or Dynacon overfill protection system. Molded from heavy-duty, fuel-resistant polyurethane with stainless steel contacts, the assembly is engineered to survive continuous exposure to petroleum products, hydraulic fluids, UV, abrasion and the repeated connect/disconnect cycles typical of bulk liquid loading terminals.

Thermistor Overfill Protection Circuit

The plug carries a 4-pin J-slot thermistor sensing configuration that forms part of the tank truck compartment overfill sensor loop. When integrated with a Scully optic sensor and control monitor, the circuit continuously verifies sensor integrity and compartment liquid level status before and during product transfer, automatically interrupting the loading pump or closing the internal valve if a high-level condition or a sensor/wiring fault is detected. This fail-safe behavior is central to compliance with API RP 1004, OSHA and NFPA 385 requirements for Class I flammable and combustible liquid loading operations at petroleum terminals, fuel depots, chemical racks, airports and marine facilities.

Technical Specifications

Construction and Durability

Each Scully 22485 assembly uses a molded polyurethane plug body that resists cracking and swelling from prolonged fuel contact, paired with corrosion-resistant stainless steel pin contacts for reliable electrical continuity across thousands of mating cycles. The cable jacket is similarly fuel- and abrasion-resistant, allowing the assembly to be routed along tank truck frames and coiled or stored without premature wear. The green plug color coding follows Scully’s standard color scheme, which allows terminal operators and drivers to visually confirm they are connecting the correct circuit before beginning a loading operation, reducing the risk of cross-wiring between grounding, vapor recovery and overfill sensing circuits.

Typical Applications

The 22485 plug and cable assembly is used as a replacement or spare part for tank trucks, rail cars and static loading rack installations equipped with Scully overfill prevention systems. It is commonly specified by petroleum distributors, fuel terminal operators, chemical transport fleets and tank truck maintenance shops that need to keep vehicles in continuous compliance with mandated overfill protection interlocks. Because loading racks will not permit product transfer to begin without a verified, functioning overfill circuit, keeping a compliant spare plug and cable assembly on hand minimizes vehicle downtime and avoids delays at the rack.

Compatibility and Ordering

The Scully 22485 is designed to interface with Scully Intellitrol and compatible overfill monitor systems using the standard 4 J-slot thermistor connector pattern. When ordering, confirm the required cable length and the specific monitor and optic sensor combination installed on the vehicle or rack, since Scully offers multiple plug color codes and pin configurations for grounding, vapor recovery and overfill circuits that must not be interchanged.

Field Replacement and Maintenance

Because the thermistor plug and cable assembly is a wear item subjected to constant flexing, coiling and exposure to fuel vapors, terminal maintenance programs typically inspect the Scully 22485 for cracked insulation, bent or corroded J-slot pins, and continuity faults during routine vehicle safety checks. A damaged plug can cause the overfill monitor to register a fault condition and prevent the loading rack from authorizing product transfer, leading to unplanned downtime for the vehicle until the connector is replaced. Keeping genuine Scully-compatible plug and cable assemblies in stock allows maintenance teams to swap a failed connector in the field quickly, restoring the vehicle to compliant service without waiting on a full monitor replacement or a factory service visit.

Why Overfill Protection Matters

Overfill incidents during tank truck loading are among the most common causes of spills, vapor releases and fire hazards at petroleum terminals. Regulatory frameworks in most jurisdictions now require a verified, fail-safe overfill protection interlock before a loading rack will permit product transfer to begin, and many terminal operators will refuse to load a vehicle whose Scully system reports a fault. The thermistor sensing circuit carried through the 22485 plug and cable assembly is a critical link in this safety chain: it must maintain continuous, low-resistance electrical contact between the vehicle harness and the rack-side monitor for the entire duration of the loading operation, since any interruption is treated as a potential sensor failure and will trigger an automatic shutdown.

Sourcing Considerations

Because Scully uses color-coded plugs and specific pin configurations to distinguish overfill, grounding and vapor recovery circuits from one another, it is important to confirm the exact configuration required for a given vehicle or rack before ordering a replacement. Substituting an incorrect plug type can prevent the monitor from recognizing the sensor loop correctly, even if the physical connector appears to fit. Seven Star LLC works with fleet maintenance teams and terminal operators to verify the correct part number, cable length and pin configuration against the installed monitor system prior to shipment, reducing the risk of receiving an incompatible component.

Why Choose Seven Star LLC

Seven Star LLC supplies genuine and cross-referenced Scully overfill protection components to petroleum terminals, fuel distributors and industrial fleets across Oman and the wider GCC region. Our team can help confirm the correct plug configuration, cable length and compatible monitor system for your fleet, and can source complete Scully overfill prevention kits alongside our broader portfolio of process safety and instrumentation products.

Get a Quote

Contact Seven Star LLC for pricing, lead time and technical support on the Scully 22485 thermistor plug and cable assembly, or for other Scully overfill protection, static grounding and vapor recovery components for your petroleum loading operations.

Browse the full Scully range or see more Automation Accessories products supplied by Seven Star LLC in Oman and the GCC.