[c-nsp] DC powering for 3845 router

[Frank Bulk]

My bad, I wrote watts when I should have written amps, and it looks like 13
A, not 19 A, as you said.

It's just that compared to the other telco equipment they install, these
'data' devices suck a lot more power.  It looks like we're going to have to
put in another power bay as this pushes us over our current capacity (we
knew we were close, but didn't plan well enough to know that this would put
us over the limit).  Between the 7609-S and two 3845's, it appears to
require 5 feeds per side, and the fuse panel supports just 4 per side.  So
that's another fuse panel.

Regards,

Frank

-----Original Message-----
From: Mikael Abrahamsson [mailto:swmike at swm.pp.se] 
Sent: Tuesday, September 11, 2007 3:20 PM
To: Frank Bulk
Cc: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] DC powering for 3845 router

On Tue, 11 Sep 2007, Frank Bulk wrote:

> Our installers are balking at the 19 W requirements, per DC power supply,
> for the two 3845 routers we purchased.  Since we have a redundant power
> supplies, it looks like a total of 4 power supplies totaling 76 W.

Hmm, as far as I can read from:

http://www.cisco.com/en/US/products/ps5855/products_installation_guide_chapt
er09186a00802ccf2c.html

"36-60 V, 13 A, positive or negative, single or dual source"

13A at 48VDC is 624W.

Most likely the router will never use more than 13A from any given source
and I'd imagine that getting a 16A fuse per feed for this, two feeds,
shouldn't be a huge problem?

What is it they're "balking" about exactly?

--
Mikael Abrahamsson    email: swmike at swm.pp.se