Removable parts may become isolated conductors if they do not have a sufficiently low resistance path to ground to enable any static generated to safely dissipate. If this happens, high levels of charge may accumulate on the isolated part posing the risk of energetic static discharges (sparks). If this occurs in a hazardous atmosphere there will be a chance of a resulting fire, explosion or dangerous physiological shocks for operators.

Schematic diagram of a Newson Gale Earth-Rite Multipoint II static control system used to protect a piece of process machinery

Solution: Earth-Rite MULTIPOINT II ensures that all parts of the equipment are connected together and to ground by using a unique intrinsically safe monitoring system. An important design criterion of the Earth-Rite MULTIPOINT II ensures that the sum of all circulating currents does not compromise the intrinsic safety of the monitoring system. This is achieved by supplying the monitoring system from a single I.S. supply, which may be used to monitor up to eight separate points.

The system provides permissive outputs only when the ground loop resistance of each utilised channel is less than 10 ohms, as recommended in the various International standards for the control of undesirable static electricity. The Earth-Rite MULTIPOINT II may be used to provide status indication for the equipment, or automatically linked back to a control system to prevent operation until the required bonding and grounding conditions have been achieved. The system is ATEX approved for use in hazardous atmospheres and meets all current EC directives. It also carries CSA approval for use in North America.