Systems such as the Earth-Rite* range offer the best possible protection from fire hazards due to electrostatic charge accumulation and sparking, by providing both interlock control of multiple components in a single circuit and visual indicator systems to monitor grounding status to a verified true earth grounding point. However, many a time single pole clamps and other passive grounding devices are specified to connect equipment in a plant to the earth or to bond them.
In hazardous areas where combustible materials are being handled, only certified equipment should be used to prevent fire hazards due to static charge accumulation.
Why have certifications?
The ATEX/FM (Factory Mutual) approvals are crucial in such situations in that this implies the product has undergone stringent testing before certification and are capable of reliably preventing static charge accumulation from equipment upon which charge may be potentially built up. This becomes even more important when the equipment to be protected is covered or coated in any way, by paint or other coatings, rust or other deposits, thus preventing direct contact between the clamp and the base metal of the equipment it is supposed to make an earthing connection with.
These coatings must be penetrated in order to ensure a full electrical connection is achieved, as they inhibit electrical contact and thus prevent proper charge dissipation to the earth. Secondly, having made a strong earthing bond, it must remain intact throughout the process for as long as required.
ATEX-compliant equipment is thus guaranteed to prevent any mechanical sparks from the construction of the clamp itself, whether because it uses thermite reactive materials like aluminum or because it could have points where mechanical energy is stored.
FM certification means that the equipment has been extensively tested for both mechanical and electrical properties and are certified to be dependable static earthing clamps in EX/HAZLOC areas.