Original Rack Equipment from Scully™

Scully systems are the number one choice worldwide for overfill prevention, graunding and vehicle identification safety at bottom- and – louding terminals.

Control fills and eliminate spills of petroleum and liquid chemicals into tank trucks and rail tank cars

Capable of monitoring tank trucks with up to eight compartments when equipped with two-wire sensors or 15 compartments when equipped with five-wire sensors

Superior system compatibility and performance when connected to tank trucks or rail tank cars outfitted with Scully sensors

Overfill prevention control monitor diagnostics

  • Tests for proper performance of all Scully terminal overfill prevention control monitors
  • Ensure that your Loading Rack Control Monitors are functioning properly and will allow properly equipped vehicles to load
  • FM & ATEX approved

Scully Rack Tester


  • Simulates Optic and Thermistor Overfill Sensors
  • Simulates Scully Ground Bolts & Ground Balls
  • Simulates Scully T.I.M.™ Truck Identification Modules


Power Supply: Powered by loading rack control unit under test
Dimensions: 27.4 cm long x 24.8 cm wide x 12.1 cm high
Weight: 2.86 kg
Connection: The rack controller plug connects to one of three style sockets on the front of the tester.
Approvals: The Scully Rack Tester has safety approvals as an intrinsically safe testing device for use in: Canada and the United States:Class I, Division 1, Groups C & D, T4Class I, Zone 0, AEx ia IIB T4 GaClass I, Zone 0, Ex ia IIB T4 Ga
Entity Perameters Ui = 15V, Ii = 250mA, Pi = 1.0W, Ci = 1.25μF, Li = 0, Um = 15Vdc, Pollution Degree 2, Ambient temperature for all ratings, (Ta ≤ 0°C ta ≤60°C) at 95% humidity, Maximum Altitude = 6562 ft. (2000 m)



The only control system that offers overfill prevention, static grounding, and vehicle identification all-in-one unit. The ultimate in terminal loading safety with a patented design that continuously monitors the relay contacts—for petroleum and chemical loading racks


  • Automatic detection of two-wire optic/thermistor or five-wire optic vehicle sensors
  • Monitoring of up to 8 two-wire or 15 five-wire vehicle sensors
  • Complete visual diagnostic display of overfill sensor’s status as well as vehicle static grounding conditions; will not permit loading under any fault or wet sensor condition

Plug & Cable Assemblies with Sculcon Series Junction Box

Designed for use with the intrinsically safe output circuits of Scully’s Intellitrol, ST-35 or ST-15 Terminal Control Monitors. Used to connect the Scully loading rack monitor to the vehicle mounted socket.


  • Extremely rugged petroleum-resistant design which can withstand harsh environments and mishandling
  • Permanent socket locator pins that won’t loosen or back out
  • Internal cable retention clamp to prevent cable pull-out or twisting
  • The plugs and cables are the pathway for the control unit, sensor signals, ground bolt and T.I.M. Truck ID module which monitor the status of overfill prevention, electro-static grounding and vehicle identification during loading operations

ST-47 Groundhog Static Ground Proving Control Unit

Self-proving technology based on Scully’s original patented design. Can operate in conjunction with your Scully Overfill Prevention System (ST-35® or ST-15) or as an independent ground verification unit. Immediately shuts down the loading operation if proper static grounding is not detected.


  • Can be used with a variety of loading operations including tank trucks, rail tank cars, aircraft refuelers and tanks to ensure that transport vehicles are properly tied to ground before and during the loading operation
  • The ST-47 Static Grounding system continuously monitors the ground connection and if that connection is lost, the ST47 will non-permit
  • For stand-alone grounding without overfill prevention, choose the junction box with choice of Scully ground-proving plug or grounding clamp
  • For static ground verification in conjunction with your Scully Overfill Prevention system, wire the ST-47 through your Overfill Prevention Control Monitor and plug and cable for one quick overfill protection and static grounding/earthing connection
  • Direct earthing tie-in point at loading rack is available