Also, some AC circuit breakers are of a design that counts on the magnetic
properties of AC, and, therefore, won't trip due to ANY DC load. I think
these are mostly not available any more, but I remember encountering them
some time ago and realizing that it would be _REALLY_ bad if someone put
th
Thus spake Robert E. Seastrom <[EMAIL PROTECTED]>:
> "Stephen Sprunk" <[EMAIL PROTECTED]> writes:
>
>> Thus spake joe mcguckin <[EMAIL PROTECTED]>:
>>> It only takes 30ma to put your heart into atrial fibrillation. In
>>> the usa, gfi's are set to trip at 5ma.
>>
>> Did you mean 5A, or am I misund
I deny saying:
> But they are there for reason. They are typ. full of power to
powDer
--
A host is a host from coast to [EMAIL PROTECTED]
& no one will talk to a host that's close[v].(301) 56-LINUX
Unless the host (that isn't close)
"Stephen Sprunk" <[EMAIL PROTECTED]> writes:
> Thus spake joe mcguckin <[EMAIL PROTECTED]>:
> > It only takes 30ma to put your heart into atrial fibrillation. In the
> > usa, gfi's are set to trip at 5ma.
>
> Did you mean 5A, or am I misunderstanding GFIs?
it's 5ma. http://www.national.com/ds
In message <004f01c2b018$4ac14900$[EMAIL PROTECTED]>, "Stephen Sprunk" wr
ites:
>
>Thus spake joe mcguckin <[EMAIL PROTECTED]>:
>> It only takes 30ma to put your heart into atrial fibrillation. In the
>> usa, gfi's are set to trip at 5ma.
>
>Did you mean 5A, or am I misunderstanding GFIs?
>
No --
Unnamed Administration sources reported that Stephen Sprunk said:
>
>
> > It only takes 30ma to put your heart into atrial fibrillation. In the
> > usa, gfi's are set to trip at 5ma.
>
> Did you mean 5A, or am I misunderstanding GFIs?
5ma is correct.
It takes very little current to cause fibri
Unnamed Administration sources reported that Robert E. Seastrom said:
>
> Bottom line is that one should buy breakers and fuses that are
> designed for use in DC powerplants, rather than trying to cheap out
> with something you picked up at Home Depot or Pep Boys. I'm sure I'm
> wasting my breat
Thus spake joe mcguckin <[EMAIL PROTECTED]>:
> It only takes 30ma to put your heart into atrial fibrillation. In the
> usa, gfi's are set to trip at 5ma.
Did you mean 5A, or am I misunderstanding GFIs?
> Normally 48VDC wouldn't be considered a 'lethal' voltage (I've talked
> to telephone technic
"Barton F Bruce" <[EMAIL PROTECTED]> writes:
> Typical 120/208V small branch circuit breakers in small buildings and homes
> have an interrupting capacity rated at 10,000 amps, and should not be
> deployed where that can be exceeded. It will be on the label.
It's worth noting that the interrupt
A few points:
Below 50 volts, anyone can do the wiring. No licensed electrician is needed
im most jurisdictions.
Total fault current available determines the damage that will be done when
something like a wrench falls across bus bars. Time, too, counts. If you
can't vaporize the whole wrench bef
s although in this case it was a large
> battery bank in a submarine but I was curious about the 48V sources in
> switch rooms.
>
>
>
> - Original Message -
> From: "David Lesher" <[EMAIL PROTECTED]>
> To: "nanog list" <[EMAIL PRO
Thus spake "Scott Granados" <[EMAIL PROTECTED]>
> Is 48V DC at the amps present normallyin switch rooms etc enough to cause
> electricucian? I have seen bad things with wrenches dropped across
> batteries even 12 volt car batteries although in this case it was a large
> battery bank in a submarin
Thus spake "Wayne Bogan" <[EMAIL PROTECTED]>
>
> For those AC only powered units, you can also purchase an invertor for DC
to
> AC conversion. You would then have the advantages of DC for your AC
> equipment. This does, however, add the potential of another point of
> failure such as fuses or br
David Lesher" <[EMAIL PROTECTED]>
To: "nanog list" <[EMAIL PROTECTED]>
Sent: Sunday, December 29, 2002 4:43 PM
Subject: Re: DC power versus AC power
Unnamed Administration sources reported that Michael Painter said:
>
>
>
> > > But, as Stephen already el
Unnamed Administration sources reported that Barney Wolff said:
>
>
> > I'm surprised you're still around after a sub battery accident.
> > They're a grade up from most CO's in available current, I'd bet.
>
> I'd bet the other way. CO battery has to supply ring current, dial
> tone and voice c
Ouch...
nas-corp.com is rejecting me for "profanity"
Was it the 'sweaty' or the posterior term?
Jeeze
--
A host is a host from coast to [EMAIL PROTECTED]
& no one will talk to a host that's close[v].(301) 56-LINUX
Unless the host (that isn't close).po
Unnamed Administration sources reported that Michael Painter said:
>
>
> I've laid across the buss-bars before...definitely an uneasy feeling, but never
> felt it unless I was sweaty.
> Capability of thousands of Amps, but it's the old "power transfer"
> deal...internal resistance of the sourc
Just some musings...
Been watching this discussion for a couple loops now. I have to say you're
both right on certain things, and that each individual design has to be
done on the merits of the need for 100% uptime vs what's tolerable.
AC is always easier to run, as the conductors are smaller
s pop.
- Original Message -
From: "David Diaz" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>; "nanog list" <[EMAIL PROTECTED]>
Sent: Sunday, December 29, 2002 5:45 PM
Subject: Re: DC power versus AC power
>
> While I would normally think some of this exa
While I would normally think some of this exaggeration. When I was
at Netrail, I did a road trip to upgrade a facility in DC. It's
kinda amazing what passed for colo in those days. The little UPS
actually had a string of Pet boys car batteries. Nathan Estes
dropped a wrench into the batter
On Sun, Dec 29, 2002 at 08:11:46PM -0500, David Lesher wrote:
>
> I'm surprised you're still around after a sub battery accident.
> They're a grade up from most CO's in available current, I'd bet.
I'd bet the other way. CO battery has to supply ring current, dial
tone and voice current, not jus
>
> Unnamed Administration sources reported that Scott Granados said:
> >
> > Is 48V DC at the amps present normallyin switch rooms etc enough to
cause
> > electricucian? I have seen bad things with wrenches dropped across
> > batteries even 12 volt car batteries although in this case it was a
l
- Original Message -
From: "Scott Granados" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>; "nanog list" <[EMAIL PROTECTED]>
Sent: Sunday, December 29, 2002 3:40 PM
Subject: Re: DC power versus AC power
>
> Is 48V DC at the amps present
Unnamed Administration sources reported that Charles Sprickman said:
> Additionally I wonder why non-conductive tools wouldn't be the norm in an
> environment where there's an "open" power grid? :)
"Fools rush in where."
It was in years past. I recall how excited the power room guys
were
Unnamed Administration sources reported that Scott Granados said:
>
> Is 48V DC at the amps present normallyin switch rooms etc enough to cause
> electricucian? I have seen bad things with wrenches dropped across
> batteries even 12 volt car batteries although in this case it was a large
> batte
7;t be the norm in an
environment where there's an "open" power grid? :)
Charles
>
>
> - Original Message -
> From: "David Lesher" <[EMAIL PROTECTED]>
> To: "nanog list" <[EMAIL PROTECTED]>
> Sent: Sunday, December 29, 2002
rooms.
- Original Message -
From: "David Lesher" <[EMAIL PROTECTED]>
To: "nanog list" <[EMAIL PROTECTED]>
Sent: Sunday, December 29, 2002 4:43 PM
Subject: Re: DC power versus AC power
>
> Unnamed Administration sources reported that Michael Painter sa
Unnamed Administration sources reported that Michael Painter said:
>
>
>
> > >But, as Stephen already eluded to... Compared with an AC plant design, to
> me, one of the biggest drawbacks of a DC plant is safety (I have had to
> kick a fellow worker away from the rack before). <<
>
> What was
- Original Message -
From: "Kuhtz, Christian" <[EMAIL PROTECTED]>
To: "Wayne Bogan" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
Sent: Sunday, December 29, 2002 9:37 AM
Subject: RE: DC power versus AC power
> >But, as Stephen already eluded t
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
- --On Sunday, December 29, 2002 00:46:56 -0500 [EMAIL PROTECTED] wrote:
> Does anyone actually wire up
> both the A side and B side to a single DC power supply and use diodes to
> keep the two supply grids separate?
We've built a number of "joiner
> Switched power supplies really don't care about the quality of the
> sine waves that feeds them, as long as they have energy to put into
> the "tank". On the other hand, video monitors like sine waves, and
> they may not get along with DC inverters/rectifiers (or even portable
> AC no-breaks
| Not to mention additional cost of wasted electricity (which does add up
| significantly when it is anything but a spot solution) and pitfalls of
| inverters (like their imperfect sine waves). And if you're putting spot
| solution UPS units out into the bottom of a particular rack, be ware thei
rk.
Of course, this is all IMHO and I've been wrong before.
Thanks,
Christian
-Original Message-
From: Wayne Bogan [mailto:[EMAIL PROTECTED]]
Sent: Sunday, December 29, 2002 1:06 PM
To: [EMAIL PROTECTED]
Subject: Re: DC power versus AC power
- Original Message -
From: "
-
From: "Stephen Sprunk" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
Sent: Sunday, December 29, 2002 1:58 AM
Subject: Re: DC power versus AC power
>
> Thus spake ip dude <[EMAIL PROTECTED]>:
> > Hello NANOG group. I am trying
Thus spake ip dude <[EMAIL PROTECTED]>:
> Hello NANOG group. I am trying to make a case for using DC power
> supplies versus AC power supplies for typical IP networking
> equipment. Is there any published whitepapers detailing this subject?
> Do you have any suggestions to aide my argument?
Most
On Fri, 27 Dec 2002, Scott Granados wrote:
> It is likely that in many settings during power failures transition from ac
> street power to ac generator power will have some lag and during that time
> your hardware could loose power. This of course depends on ups systems in
> use and many factors
It is likely that in many settings during power failures transition from ac
street power to ac generator power will have some lag and during that time
your hardware could loose power. This of course depends on ups systems in
use and many factors. Dc usually however is clean in its transition and
37 matches
Mail list logo
