There are a number of potentially issues. Safety being one. There are
also operational issues.
I would say most of the time there will be no noticeable difference.
The one really noticeable differences would be if there were a short and the
case became live. You may become not live.
grounding helps prevent static charge damage, computers are highly
sensitive to this.
walk across room in dry weather on say carpet, touch computer feel
ungrounded shock can and will damage computer. maybe not stop it just
slow its operations permanetely. besides the hazard if the case gets
electrically hot that can kill.
ground the computer properly
I'm not saying that you shouldn't ground
your computer, but, most of
the times static causes a problem,
grounding probably wouldn't help.
When you get all charged up with static
electricity, you typically touch the
mouse, keyboard and those, in today's
plastic age, do not have grounded
(metal) cases. This could destroy the
keyboard or mouse itself, but can
also destroy the ports on the motherboard.
You can avoid shock hazards with a GFCI receptacle, even if no ground
However, if you do this, you might as well leave out the surge
plug the equipment right into the wall. Surge protectors use varistors
high-voltage surges and spikes to ground. No ground, no short, no
This is why some have a 'grounded' light. Without a functioning
useless except as a multi-outlet strip.
I once worked in a large big name retail chain. With over a hundred
computer cash registers static was a big problem. It knocked out more than
one during the day. All kinds of solutions were tried. As it ended up two
worked. First was my suggestion of anti-static spray, renewed twice a week
(turned out that ended up being my job) and about two generations later the
equipment become less sensitive.
When working for a State agency, they had one employee who knocked out
printers, computers and anything electronic. This time it took both
anti-static pads (grounding pads) and spray both.
In short, I would suggest you get them grounded for what you are worried
about, and for what you are not worried about and should. Machines are
easier to replace than people.
I made all my female employees show me their panties, privately, before work
to guarantee they weren't wearing nylon!
After implementing this plan, static discharges stopped.
I also sprayed the floor, before anyone else got to the shop, with my own
mixture of 2 tbls fabric softener to 1 pint of water, but I don't think that
had anything to do with the static electricity. No, I'm quite convinced it
was my panty-diligence that did the trick. Heck, in cases where there was
some doubt, I had the ladies LEAVE their panties in my office during their
Grounding addresses numerous issues. Same wire may perform
different functions. Others have noted an obvious and first reason for
third prong ground wire - human safety. If using only two wire
receptacles, then a GFCI can be installed as a kludge and legal
alternative to missing safety ground in wall receptacle. GFCI
installed either in receptacle or in breaker box.
Safety ground wire also is part of protection to interconnected
equipment - data lines. Even if equipment does not connect to building
safety ground, still, all should interconnect their third prongs to a
common point. A $3 power strip will interconnect equipment ground
prongs. This grounding function is especially useful for devices that
use common mode signaling such as RS-232 serial ports and Centronics
type printer interfaces. Common point grounding performed to
protection interface drivers AND to reduce failure do to signally
Third function: static electricity involves a completely different
circuit. Safety ground is not relevant. Items in a room not normally
considered electrical conductors are good conductors for static
electricity. In a simplest example, static electricity current flows
out via fingers, through electronics, down table into rug, and then
back to your shoes. A complete circuit necessary for electric current
flow. Safety ground need not be part of this circuit. Furthermore,
better manufacturers conductively 'paint' inside of cases and keyboards
so that a static discharge gets into that floor without passing through
electronics. IOW, if that common AC electric ground device (ie power
strip) is metal and in contact with the floor (or an anti-static floor
mat), then equipment ground (third prong) wire would conduct a static
electric discharge direct to floor (and shoes) without passing
destructively through any electronic circuits.
A static discharge mat in front of keyboard that discharges to floor
(even through table) might discharge hands before touching a keyboard.
Again, this type grounding is about discharging back to floor and shoes
- a different type of grounding that may or may not use equipment
ground wire. That internal conductive paint made more effective when
it somehow connects to floor.
I service office machines for a living and such line to case shorts do
occur. the cause no power, blown machine or main breaker troubles.
ungrounded they cause no trouble till you touch the case, ZAP
the reason you dont hear of it happening is because the vast majority
of devices today are grounded.........
frankly I would rather avoid getting shocked altogether and want my
computes to run well.
both of these arent supported by a ungrounded outlet:(
Not so "vast" in the majority anymore.
Neither of my "ink jet" printers has a ground. The laser printer does as
do the monitors and main computers. Most stuff that's powered from a "wall
wart" isn't hard grounded. (All these might have a deliberate "leakage"
to the power conductors.)
actually, dying on the way to the supermarket would be much greater...
I've never heard of a power supply shorting to the case of a computer,
although, if it did... and you were able to complete the circuit
somehow (assuming it didn't blow it's internal fuse, or your breaker)
you would die as the amperage is definitely enough to stop your
heart.... but you are definitely more likely to get run over, struck by
lightening or stoned to death by angry union workers walking to the
Back to your original question, I have run all kinds of computer
equipment on non-grounded outlets...In fact, I had to rip the third
prong off my old APC surge protector about 5 years ago when I moved
into a rental with only two prong outlets, so technically all my
equipment was un-grounded until I recently bought a surge protector
from walmart for $25 (sales are great)
Speaking of that $25 surge protector, it has a "grounded" indicator...
that obviously isn't glowing "ON" as my outlets aren't grounded (I'm
lazy, and my insurance is paid up). I have no idea how a ground
indicator works, but I guess surge protectors are starting to be smart
enough to know when their owners are cheating them out of an earth
ground for their precious little circuits.
Grounding my outlets (I own quite a bit of electronic equipment, btw)
is on the bottom of my to-do list. And, as far as static is
concerned... I've been in IT for years, around a lot of delicate
computer chips and servers....and not once have I experienced any sort
of problem with static, and I've never cared to use a wrist strap or
any of those other gizmos. But this is my experience and as soon as I
burn out a stick of memory by rubbing my feet on the carpet I'll listen
to yours. ;-)
Valley Center, KS
And, as far as static is
I have had problems with static electricity. I had a
laptop that I kept drawing an arc from when I touched
it. And the arc was returning to ground through the
LAN cable. It burned out the port on the router.
Fortunately there was a spare port on the router,
but it was not a good thing.
After that I rigged up a ground wire that I connected
to the laptop to make sure the case was grounded.
The odds are low because most cases are grounded and therefore
protected. All legal non-grounded cases are double insulated and there for
protected in a different manor. If a computer or other equipment has a
grounded cord, it is not smart to think that it would have double
I have gotten 120V shocks before. It's not something I'd want to
happen, but far from something that could be fatal. Of course, I
didn't stand in a bathtub full of salt water and stick a hot wire in
Actually, I described the experience as like having a thousand
hyperactive ants just under the skin.
The fatal effect may come from a response to the unexpected sensation,
such as falling off a high roof onto concrete. Try to avoid doing
electrical work while standing in a precarious position.
It could indeed be fatal. It's all a matter of how long, how good
a ground, and where it goes through you. Anything 50v or more
should be treated with respect, and favorable situations for
electrocution are not as uncommon as it seems.
Im not worried about myself but thought a major surge or lightning would
have nowhere to go without a ground, I would think my surge supressor
forces any spike to ground . Static is another reason to use a ground I
Ground for static electricity is not same ground for lightning.
Conductive paint inside a computer's plastic case connected to floor -
a ground for static electricity - would mean that electrical current
does not flow destructively through electronics.
Lightning needs a different ground - earth. Wire is not a perfect
conductor. For example, a wall receptacle safety ground may measure
less than 0.2 ohms resistance to the earth ground rod. But same 50
foot wire connected to breaker box might be 130 ohms impedance.
Electrical characteristics of that transient are important. A trivial
100 amp lightning transient might see (less than) 12000 volts between
wall receptacle and breaker box. Where is the protection? 12,000
volts would then find other (and destructive) paths to earth because it
was permitted near to electronics. Again, the word for this transient
is 'impedance' - and why lightning must be earthed where it enters a
Grounding for lightning is where utility wires enter a building.
Effective lightning protectors ground to earth. Grounding for static
electricity means an electrical connection from hand to floor and shoes
that does not pass through electronics. That ground is somewhere in
that 'hand to floor' circuit.
Electrical switch specifications often claim protection from up to
20,000 volts. That means no static electricity passes from hand into
switch electrical contacts. What is not always obvious? That 20,000
volt protection does not exist if the switch body is not properly
connected to chassis ground. Again, what is the discharge path? If
electricity comes out of finger, then what is other side of that
'battery' or 'charged capacitor' that is being discharged? Only
relevant ground is a point in that circuit. For static electricity,
earth ground is not part of the circuit - not relevant.
For different types of destructive transients, first define the
complete electrical circuit. Only then is one point is that circuit
The IEEE guide to surges and protection at:
describes plug-in suppressors as clamping the voltage on all wires
(signal and power) to the common ground at the suppressor. Earthing is
not the primary mode of protection.
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