The Earthing Relay Model ERX-710 is an Intrinsically Safe field-protection device used in Vehicle Static Grounding Systems. It provides the operator with absolute confirmation that the Vehicle is properly earthed and is consequently safe for loading or unloading operations. The instrument thus ensures safety during the loading and handling of volatile chemicals or inflammable liquids at truck, rail and aircraft refueling terminals.
Transport Vehicles, particularly of inflammable, explosive or sensitive material should be necessarily grounded before, as well as during, any loading or unloading operation. One of the primary causes of fire and explosions during such operations is the danger of accidental sparking which may be caused by the generation of a high static-charge on the body surface or chassis of the vehicle. Since the tyres of the vehicle are made of a non-conductive material, there is no path available for the discharge of this developed static-charge. On entry at the loading / unloading terminal, the Tanker is first earthed to the “true-Earth” (Ground) point by means of a Clamp Probe and the static-charge is dissipated. Even a low level residual static-charge could result in minor sparking on contact with any metallic dispensing hose or valve, which could spell disastrous repercussions in a hazardous area. The Earthing Relay ensures that this residual charge is dissipated through an internal shunt route, and then re-checks to ensure ground potential of the truck body.
The instrument has been tested and certified for Intrinsic Safety by The Central Mining Research Institute (CMRI) at Dhanbad for suitability of operation in Gas Groups IIA and IIB. The Earthing Relay Card itself is housed in an explosion-proof enclosure, which is certified for operation in Gas groups II-A and II-B by CMRI Dhanbad and CCOE, Nagpur.
All ASHE instruments carry a lifetime warranty against defects in components and workmanship.
Series ERX and SGR Static Charge Grounding System (Earthing Relay)
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1 to 10 Ohms (internally settable)
230 V AC,50 Hz ( 20%) AC power supply
170 x 325 x 250 mm
Max Ambient Temperature
50 deg C
The Static Charge Grounding Systems, Series ERX and SGR, provides safe and secure grounding of dangerous static charge to earth during loading or unloading operations in hazardous area applications, ensuring safety to plant and personnel. The instruments are certified intrinsically safe products offered in explosion-proof execution, providing a high degree of protection against fires or explosions caused by sparking.
The instrument acts as an interlock during loading and unloading operations, allowing the process to resume only after satisfactory grounding of static charge on the Tanker body or Loading Arm. The Earthing Relay''s primary function is to determine whether the Tank Trucks at the loading terminals are properly earthed and thereafter, provide a visual indication and a control signal for process resumption. The Earthing Relay senses the static-charge potential of the Tanker and provides a safe grounding path for this charge through a low impedance and intrinsically safe electronic module, which is itself housed in an explosion proof enclosure mounted near the loading terminal. The Earthing Relay Series ERX & SGR are certified for intrinsic safety (Ex-i) and the enclosures for explosion-proof (Ex-d) operations by CIMFR. The instrument is housed in a certified cast Aluminum Alloy LM6 enclosure and offered with a standard 5-metre Cable-Clamp assembly. All ASHE range of instruments carry a lifetime warranty for design and workmanship.