"No Shock Shopping"

February 19, 2007
By Steve Fowler, Publisher
http://www.sfowler.com
sfowler@sfowler.com

We are reminded everyday of static electricity. When we go shopping many times the action of rolling the cart across the floor generates high potentials. Then we get zapped as we reach for the can of peas. Most stores do little or nothing to make this problem better. Some of the larger discount stores are the worse offenders.

Well, one grocery store chain has finally taken a stand on getting the static potentials reduced. Food Lion has begun to put drag wires on the carts.

The floors are not static dissipative but they are on grade level and over concrete. The use of wires instead of chains was a good idea. Even though the floors have little surface conductivity, the pointed wire helps connect to what conductivity is there but more importantly the wire can corona ionize the cart to the concrete with very good effects.

This author performed a very unscientific experiment at the Food Lion. One has to be careful not to look suspicious walking through a grocery store these days.

I walked briskly around the store with a cart which had not wire attached. The humidity was approximately 20% RH at 70 degrees F during my walk. I achieved almost 8 kV on myself holding the cart.

When using a cart with the wire, I could not get above 3 kV and it drained fairly quickly. Looks like it works.

Remember that a person can not feel a static shock of less than about 3 kV. This means that the wire would keep the shocks below most people's threshold of perception.

Of course on another day, the numbers could be higher for the ungrounded cart but I suspect not for the cart with the wire.

This not only will make shopping there more comfortable, it will help keep the checkout computer system from crashing as well as the point of sale credit card systems from glitching. Not to mention the destruction of the smarts in "Smart Cards."

Good work Food Lion.