The STS300 Ground Verification System provides a positive ground indication through the use of an intrinsically safe monitoring circuit driving a switching relay. Upon connection of the self-releasing clamp and cable to a conducting material, the intrinsically safe circuit is completed and the operator will be shown a green light to indicate that a ground connection has been established.

While most competing systemsn only monitor the path from the ground unit to the clamp, the STS-300 also employs a segregated cable connection to actual ground, which is also monitored for low resistance. An interuption in either path (indicated by resistance aboue 5 ohm) will shut the system down.

The system can also be interlocked with filling equipment to ensure that no flammable product can be transferred until the ground is established. If the circuit is broken by release of the grounding clamp or other ground interruption, the contact relay will open and a red light will be displayed. Any filling equipment that is controlled by the system will also be halted until the ground is re-established.

The STS-300 system will do the following: shut down a pump or valve; sound an alarm; show a red light when conditions are unsafe; show a green light when conditions are safe; open contacts on a computer; indicate that static path to ground has integrity and receive permissive signals for a computer control.