[54400] in North American Network Operators' Group
Re: DC power versus AC power
daemon@ATHENA.MIT.EDU (Michael Painter)
Sun Dec 29 20:37:42 2002
From: "Michael Painter" <tvhawaii@shaka.com>
To: "nanog list" <nanog@merit.edu>
Date: Sun, 29 Dec 2002 15:37:24 -1000
Errors-To: owner-nanog-outgoing@merit.edu
----- Original Message -----
From: "Scott Granados" <scott@wworks.net>
To: <wb8foz@nrk.com>; "nanog list" <nanog@merit.edu>
Sent: Sunday, December 29, 2002 3:40 PM
Subject: Re: DC power versus AC power
>
> 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 submarine but I was curious about the 48V sources in
> switch rooms.
I've laid across the buss-bars before...definitely an uneasy feeling, but never
felt it unless I was sweaty. <g>
Capability of thousands of Amps, but it's the old "power transfer"
deal...internal resistance of the source vs. internal resistance of the load (your
body).
--Michael
>
>
>
> ----- Original Message -----
> From: "David Lesher" <wb8foz@nrk.com>
> To: "nanog list" <nanog@merit.edu>
> 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 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 the worker doing? Is this 48 VDC?
> >
> > Bet so.
> >
> > And note, it's not just ISP's, of course. I heard that Sprint
> > PCS ha[s,d] a Dallas tech in critical condition and a dead switch
> > after a dropped wrench & resulting fire.
> >
> > In the words of Phil Esterhaus:
> >
> > Let's be careful out there....
> >
> >
> >
> >
> >
> > --
> > A host is a host from coast to coast.................wb8foz@nrk.com
> > & no one will talk to a host that's close........[v].(301) 56-LINUX
> > Unless the host (that isn't close).........................pob 1433
> > is busy, hung or dead....................................20915-1433
> >
>
