Joan Rapier wrote:

> I've had several clients ask questions of me lately related to the
> necesity of grounding their computers and peripherals.  I've found
> myself at a loss when trying to explain.  I realize that's because I
> don't fully understand the electronics of using an earth ground myself
> beyond its function as a sort of "safety valve".
> I'd be greatful if any of you double eeez or otherwise knowledgeable
> 'tron folks could explain this to me.
>
> [1]Why is it important to have (earth) ground connected to one's
> computer or any appliance, equipment, etc. that has three-pronged AC
> plugs?

The reason of grounding has to do with electrostatic charges that forms
when you handle different types of material. (Yes, the famous hair-standing
experiences)

Electronics chips are delicate devices, their tolerance for voltages are
pretty low.  If the input voltages are too high, the current surging
through the transistors can burn them out.
(Imagine the Missisipi flooding its bank when the rainfall volume is too
high)

So, when you touch electronics device and you have a electrostatic charge
on you, a voltage potential is form between the device and you.  (like the
Hoover Dam, potential forces are build up)
The potential difference then induce a current in the electronics,
rendering it useless.

> [2]Is it the case that earth ground plays an integral role in the
> engineering and function of any surge suppressor, UPS, or line
> conditioner?

The earth ground is conventionally use to discharge the electrostatic
potential that can build up.  Of course this is not absolutely required,
just as long as the device and you are at the same potential.
Thus, a sufficiently large conducting surface can be use to reduce your
potential vis a vis the device, better still if the electronics are
connected to the same surface.

> [3]If someone is moving into a home whose outlets are not grounded (to
> do so would be very costly as the concrete foundation is not raised),
> how might they protect their sensitive electronic equipment like
> computers and peripherals?

See above.  However, does your local Buidling Code allows ungrounded
electrical mains?

> [4]In the case of number [3], is using GFI outlets their only option?
> [5]Can one assume that, if an appliance, computer, etc. has a
> three-pronged outlet that its circuitry is designed to exploit the
> advantages of earth ground in the event of over-current or over-voltage?
>
> TIA
> Joan Rapier
>
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