David Nebenzahl wrote:
On 4/11/2011 1:48 PM Sjouke Burry spake thus:

David Nebenzahl wrote:

On 4/11/2011 12:55 PM so spake thus:

Ever need an extension cord at home and all you can find are the two-
prong type? (My wife seems to buy them in bulk). Why do they even make
a 2-prong type when all outlets are supposed to have a ground anyway?
Short answer: because there are lots of things you can plug in that have
2-prong plugs. (I ASS-ume you're talking about US/North America?). Most
of them are perfectly safe and don't need a ground (double insulated, etc.)

The code (NEC) doesn't have total control over each and every device
that gets plugged into an outlet. And 2-prong cord sets may still be
UL/CSA approved.

I've told the wife to never buy a 2-prong extension cord.
I wouldn't sweat it, unless you have a lot of stuff with grounded plugs
and have to use lots of 2-to-3-prong adapters (which does get really
annoying).

Grounding is a Good Thing, but its benefits are still often wildly
overstated. I've worked on plenty of houses around here with old wiring
(no separate ground conductor), and for 99% of devices they're perfectly
OK. Even computers and other "delicate electronic equipment".

I have just blown 2 soundcards, by connecting those two while
on 2-prong outlets.......

I replaced the cards, and about 8 2-prong outlets.

I'm surious: just how did that happen? Did you plug 2 things into two
different outlets? Otherwise, hard to see how you could blow a soundcard
just by plugging a computer into a 2-prong outlet.

And I'm ASS-u-ming that your new outlets are actually grounded? Of
course, installing grounded outlets won't help you in an old house which
has 2-wire circuits.


Both computers were on 2-prong.
In which case (I should have known at the time), there is
about half the net voltage on the case, because of the
netfilters build into the computer.(duuu...)
I connected the line input of one computer to the line out
of the other computer, with a 2-male small connector cord.
Well, the tip of that connector touches ground on the
computerside first, when inserting, inputting ~100 volt into the other
computer, and that was definitely that.
Now why both cards were gone, is harder to explain, unless the
other card had a floating ground, in which case you can kill both
cards.....
But I have no schematics for those two cards, one of which was build
into mother board card.
Luckily the bios allowed to disable the malfunctioning chip.
7 euros for one soundcard and an old soundblaster for for the other
(old)computer, restored things.