The instrument is a certified intrinsically safe product mounted in an explosion-proof enclosure. The instrument detects the presence of a Tanker vehicle and interlocks the loading and unloading operations allowing the process to initiate only after satisfactory grounding of the Tanker body or Loading Arm and healthy physical condition of the interconnecting Cables. The charge is thus safely dissipated to earth via a low impedance path through an intrinsically safe module housed in a flameproof enclosure in the vicinity of the operation.

The Earthing Relay assumes "intelligence" by the fact that it can discern connection of the probe to a Tanker vehicle as against a metallic structure, and will permit operations only when the Probes are connected in the recommended configuration. Any attempt by the operator to bypass the Earthing Device is effectively foiled, thus guaranteeing a safe operation. The instrument has a large high-bright and bi-colour LED display window with Red and Green colours prominently visible to indicate the status of the grounding operation. When the monitoring and grounding cycle is complete, the Earthing Relay provides potential free Relay change-over contacts, which may be interlocked to control the operation of the line Pumps, Batch Controllers, auxiliary instruments and any remote lamps or alarms. The operator thus receives absolute confirmation that the Vehicle is properly earthed, signalling it safe for loading or unloading operations.

The Earthing Relay ensures :

  1. Positive and verified connection of Probe to a tanker vehicle only and not to a metal structure in gantry.
  2. Verified Capacitance measurement and verification of vehicle.
  3. Verified low Resistance measurement and verification of Cable interconnections.
  4. A continuously earthed Tanker vehicle with monitoring of Cable integrity and impedance below 8 ohms (configurable upto 16 Ohms) for the duration of the product transfer process.

When these parameters are confirmed, the Earthing Relay permits the transfer of product. Any static charge generated on the tanker truck during the transfer process is instantly transferred to the Earth Pit grounding point.