ESD Systems - Questions And Answers

How effective is your Item # 14000 drag chain? What is the material of the chain? Previously, we've had problems with chains making intermittent contact possibly due to the loose chain links. - Anonymous, San Diego , CA

Our Drag Chains are made from nickel plated brass, have a 1 megohm hermetically sealed resistor in series to it's ground path and are 24" long. We've done in-house testing on this item and have never had an intermittent electrical contact (open condition) occur under normal usage. There have been cases where a rolling metal cart, even with a ground chain, can charge up to a few hundred volts because of effect of the wheels and the field induction to isolated parts. There can be times where the electrical contact resistance between the chain and cart may be compromised from either non-ESD flooring or insulative dirt layers interfering with proper contact. The wheels may play a major roll in this problem. There are advantages of the use of drag chains over dissipative wheels as they don’t get as dirty as dissipative wheels. Regardless, it is important to keep the floor clean (dry swept frequently) to keep the conductive path to ground (ESD flooring) at it's optimal level. More info on our Drag Chains can be found on our website. The drag chain is used to ground mobile carts, shelves and chairs in an ESD protected area. It is easy to install by simply attaching the 7 mm socket to a snap on the item to be grounded. The chain can also be conveniently looped around cart rack or chair leg and snapped onto itself.

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