Hello all,
The Note beneath Table 4 in ANSI/ESD S20.20 states that when work is performed on an ESDS item that sits on a packaging, then the packaging effectively functions as a worksurface, hence the resistance to ground limit for worksurfaces apply.
Could you help to define what constitutes “work” please?
Good morning Tay
In this case any physical activity that performs or carry throughs a task requiring effort or continuous repeated operations
I.E. inspecting, soldering, assembly actions, dis-assembly, ect.
Good question and asked often. Work can be defined as:
When value-add handling is performed on ESDS items, or when the physical properties of the ESDS items are altered (physical change that may be observed visually), then the action may be defined as “work”. Examples include fabricating (such as, etching layers, drilling, plating), testing (such as, open/shorts and functional), assembling (placing and soldering components) to create a functional electronic device and fixation of a fastener or applying label to an ESDS item.
The act of placing or removing an ESDS item from the packaging does not constitute “work”.
Hope this helps.
Thank you, John. Yes, this is very helpful.
Along the same lines, is it then correct to say that when a mobile equipment is used to transport ESDS items that are contained within a protective packaging like the tray or the container, the mobile equipment is not required to meet the resistance to ground limit of <1.0 e9 Ω ?
That is correct. A tray or container can be considered a package as long as the loading/unloading of the ESDS item is done while the package is grounded, either by a grounded person that handles the package or by placing the tray or container on a grounded surface.
It could even be by connecting the cart to a ground connection by a physical wire.
The key here is to ensure that during the transport, if the mobile equipment is not grounded, no one picks up or handles the ESDS item.
Thank you again, John. This helps to reduce misinterpretation of the requirements tremendously.