Friday, January 26, 2007

Can a supermarket shopping trolley really build up a static charge?

Can a supermarket shopping trolley really build up a static charge? I can see the insulated wheels having chance, but would have thought the very large surface area of metal would discharge this to the atmophere quickly enough so that a shock from the trolley would be very unlikely. I would have thought any shock from a trolley would have been a discharge of static built up on the person.

Yes, a trolley can charge up. Air is a very good insulator and does not allow charge on the trolley to escape easily unless quite high voltages (thousands of volts) are reached. The main paths that charge can leak away are through the tyres and floor, both of which can often be highly insulating, or through the person touching the trolley, through their shoes and the floor.

There are at least 3 ways in which a person could get a shock when they touch a trolley - either the person is charged, or the trolley is charged, or both are charged.

You may be interested to read my on-line articles

Static shocks and how to avoid them
Why static builds up on people

2 comments:

john said...

Dear Jeremy:
Thank you for your blog and the excellent resources on your website. My wife and I have quite a serious static shock problem in the kitchen of our rented apartment. We both get painful shocks (sometimes I've felt them in my arm or near the point of contact minutes after the shock) when touching anything in the kitchen - the tap, oven door, electrical stove range, fridge door, and even the water from the tap. I've read your site and others and decided to go barefoot in the kitchen, which has a vinyl-type floor. I'll also look for a metal thimble to touch things with. However, I am a little worried that these shocks are not actually static shocks, but, rather, the result of electrocution. When we moved into our place and cleaned out the stove range, we noticed that one of the cables connecting one of the electric coils of the stove was frayed. Our janitor claimed that it was inconsequential. Could that frayed cable be the source of an eletricity build-up throughout the kitchen? How does distinguish between static buildup due to dryness and certain synthetic materials and shocks caused by electricity leakage (?) ?
Thanks so much for your help.
Best Regards,
John

Princess Jibi said...

I am so glad I found your site... its so imformative..
I never knew so much about why I get shock and how and so and I kept asking everyone..
In my country I have never had this problem. But here in canada I noticed am getting it alot.
I once got shocked by 210 volt by the washing machine... and 110 by plugging in a loose cable.

But static shock all the time sucks...
thanks alot for all the info..