EMC implementation - Raised floors
The inclusion of the floors in the mesh contributes to equipotentiality of the area and consequently to the distribution and dilution of disturbing LF currents.
The screening effect of a raised floor is directly related to its equipotentiality. If the contact between the floor tiles is poor (rubber antistatic joints, for example) or if the contact between the support brackets is faulty (pollution, corrosion, dust, etc. or if there are no support brackets), it is necessary to add an equipotential mesh.
In this case, it is sufficient to ensure effective electrical connections between the metal pedestals. Small spring clips are available on the market to connect the metal pedestals to the equipotential mesh. Ideally, each pedestal should be connected, but it is often sufficient to connect every other pedestals in each direction. A mesh 1.5 to 2 metres in size is suitable in most cases. The recommended cross-sectional area of the copper is 10 mm2 or more. In general, a flat braid is used. To reduce the effects of corrosion, it is advised to use tin-plated copper (see Fig. R8).
Perforated floor tiles act like normal floor tiles when they have a cellular steel structure.
Preventive maintenance is required for the floor tiles approximately every five years (depending on the type of floor tile and the environment, including humidity, dust and corrosion). Rubber or polymer antistatic joints must be maintained, similar to the bearing surfaces of the floor tiles (cleaning with a suitable product).