Ed Oscuro wrote:
Since your post I've been wondering about this. I thought that the major purpose of a ground plane is to handle stray voltage or current while the device is in use - so it most directly protects communication ports, power, and other things with a connection to the outside world, or it's dealing with a device on the board that consistently dumps some small amount of extra voltage into the circuit which you have to handle for stability. Physical handling is more random; you can touch the board anywhere and if you're careless or unlucky that current spike can happen right next to a fragile component, or multiple fragile components, and travel into both. If anything I think it's just the higher design tolerances of obsolete components that protect them from being shocked to death; some modern stuff is exceedingly fragile.
I blathered on a lot earlier, but my basic view is that any non-metalized bag is only a partial solution and you can't count on it to make up for bad handling. Pink anti-static bags or bubble can only be relied on not to build up a charge when you unwrap them. The bubble wrap is more likely to provide a physical gap between you and the PCB, and probably is good enough for shipment, but it's not a guarantee. You also have to think about the physical board itself, so it has to be stored in a way that it won't sag or bend. Ex-Cyber's point about discharging batteries is interesting, too.
In the meantime I put more stock in proper handling and putting money into the things that directly help a PCB function safely, like a good power supply that delivers free range electrons hand-picked by elves in the valleys of the Swiss Alps.
By the way, since Brexit how are those anti-static wrap prices?
The ground plane's main purpose is a return path for the circuit, the minus (-) end. Making it a big plane (an entire layer of the PCB often) instead of individual lines is just more efficient. This produces a path of very low resistance and so one added benefit is catching stray static electricity. It's much easier for your spark to get to ground by the ground plane, rather than into any of the components.
And I don't get the brexit thing since I'm Canadian haha.