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

How to prevent ESD damage

When you work with solid-state devices,what may help prevent ESD damage?

A device outside and ESD Protected Area (EPA) must be protected by ESD shielding packaging. Devices should only be taken out of their ESD protective packaging when inside an ESD Protected Area in which electrostatic risks are controlled to an insignificant level. In manual handling and assembly, it is most important to ground the body of the person who is working with the ESD susceptible devices. There are many other precautions that might be needed. Please look at our ESD guide

Can electrostatic discharges harm people?

Can static electricity cause any physical damage to people?

Static electricity discharges do have significant current flow, which can be several amps or tens of amps for a few hundred nanoseconds. The stored energy which is released in a discharge is also important.

Small static discharges do not do damage to a person and may not even be felt. At the other extreme lightning is a static electricity discharge and can certainly kill. So between the two extremes we can expect there to be a range over which a person could be injured in some ways. Where that range lies, and what the effects are, is not well documented as far as I know.

There are standards which may be helpful, PD 6519-2:1988 probably being the most relevant in this case:

PD 6519-3:1999 (IEC 60479-3:1998).Guide to effects of current on human beings and livestock. Effects of currents passing through the body of livestock.

PD IEC/TR 60479-4:2004. Effects of current on human beings and livestock. Effects of lightning strokes on human beings and livestock.

DD IEC/TS 60479-1:2005. Effects of current on human beings and livestock. General aspects.

PD 6519-2:1988, (IEC 60479-2:1987). Guide to effects of current on human beings and livestock. Special aspects relating to human beings. (Under review)