WRAL WeatherCenter Blog

On Wendsday may 2 at approximatly four o' clock in the Louisburg foodlion the grocery store shopping carts were shocking people with a 2 inch arc of static electricity, regardless of shoe type. is there any weather related reason for this?

Posted May 12, 2007 12:19 p.m. EDT

MIKE MOSS SAYS:     Roxie,    That's an interesting observation! Usually, notable static electricity buildups and discharges are related to especially low relative humidity that increases the dielectric (insulating) properties of air, so that a larger charge differential is required between two nearby objects of opposite charge before generating a neutralizing spark. At the time you mentione, the Louisburg airport reported a temperature of 88, a dew point of 57 and a resulting relattive humidity of 35%. Those numbers aren't the sort that make you think of big static shocks, so I'd speculate that perhaps inside the store heavy air conditioning was lowering relative humidity to a considerably greater degree, and that may have contributed to the phenomenon. Why it was so noticeable at this store in particular is hard to say, as I think most of us have been in chilly grocery stores on days with similar weather and not seen such intense static discharges. If someone out there is an electrical engineer or otherwise has a better explanation for this, please feel free to add a comment!