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I am looking for an easy way to dissipate static from our portable scale carts (I should add that we work in a plastic injection molding plant, and use these scales to count our parts for packaging). These carts are made of steel and have white nylon caster wheels to roll on our concrete floor. These scales work in either AC or DC mode, and most of our problems seem to come from the scales when in DC mode. I was thinking of something similar to when cars used those black rubber strips hanging from their rear bumpers, and dragging on the ground to dissipate shocks, etc... I would appreciate any ideas or comments you may have to help solve this problem. - Brian D. Kuklewicz, Buffalo, NY

In DC mode (batteries), you may not have a ground connection as the AC line may be disconnected (which usually carries a ground to the equipment), so the solution would be to provide a ground cord to the chassis at all times (especially in DC mode). As long as the complete structure of the cart is conductive, then you can ground this directly to the floor via a drag chain. If the shelves are electrically insulated (i.e., plastic bushing) from the uprights then directly connecting the metal shelves to each metal upright (leg) would be required. The floor must also be conductive (suggest < 1x10^9 ohms) for the system to work (cart to remove "discharge" the static charge to ground). Use of Statproof® floor finish or paint is one way to achieve a uniform static dissipative (conductive) coating on the floor.

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