DC Power choices (was Re: Network visibility)

["Jay R. Ashworth" <jra () baylink com>]

One of the 4 or 5 datacenters in downtown Tampa had a telco or offshoot in
their spaces, when I took All The Tours about 9 years ago.  

They have 8x750MCM hauling -48VDC from their power plant to the cage in question.

On each side.

It was, in fact, pretty impressive to look at.  But I was a little worried about 
the loading on the building frame.  :-)

And while I think there might be advantages in running power supplies in gear
at -48, I'd want to rectify it in the cage, preferably from 480/3ph.

Cheers,
-- jra

----- Original Message -----
> From: "Lady Benjamin Cannon of Glencoe, ASCE" <lb () 6by7 net>
> To: "Mark Tinka" <mark@tinka.africa>
> Cc: "NANOG Operators' Group" <nanog () nanog org>
> Sent: Thursday, October 21, 2021 4:50:10 PM
> Subject: Re: Network visibility

> Outside the datacenter is where DC power really shines in my opinion.  Inside
> the DC, everything is AC now and probably for the best.
>
> We never came up with a modular standard for -48VDC. Perhaps that could have
> changed things.
>
> But it sure is nice having 72hrs of battery run time in the field/edge -
> although those are becoming mini data centers themselves and are in turn also
> slowly going AC.
>
> Ms. Lady Benjamin PD Cannon of Glencoe, ASCE
> 6x7 Networks & 6x7 Telecom, LLC
> CEO
> lb () 6by7 net
> "The only fully end-to-end encrypted global telecommunications company in the
> world.”
>
> FCC License KJ6FJJ
>
> Sent from my iPhone via RFC1149.
>
> > On Oct 20, 2021, at 10:19 PM, Mark Tinka <mark@tinka.africa> wrote:
> >
> > 
> >
> > > On 10/20/21 20:37, Lady Benjamin Cannon of Glencoe, ASCE wrote:
> > >
> > > -48VDC power is still the best.
> >
> > I really envy folk that love DC for networking gear :-).
> >
> > Work in 2007 was an all-DC network. I rebuilt it into AC, considering the ISP
> > also owned the data centre (most of whose customers bought AC). The space we
> > freed up and the ease of deployment was night & day.
> >
> > Currently, we obviously need DC for the terrestrial Transport and wet plants
> > (because that's just how classic telco rolls), but I also switched all IP/MPLS
> > gear to AC soon as I arrived. Heck, even the Arbor (now Netscout) gear, as well
> > as the HP server rack, was loaded with DC power supplies. Those things just had
> > to go.
> >
> > There is an avenue of pleasure in not having to spend inordinate amounts of time
> > adding major electrical planning to deploying/decommissioning a router, switch
> > or server.
> >
> > But yeah, I know the AC vs. DC discussion can become a rat hole.
> >
> > I'm aware of data centre operators now providing DC as an option for their
> > expansion projects, when they previously had it as the norm, FWIW.
> >
> > Mark.

-- 
Jay R. Ashworth                  Baylink                       jra () baylink com
Designer                     The Things I Think                       RFC 2100
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