nanog mailing list archives
Re: DC power versus AC power
From: jlewis () lewis org
Date: Sun, 29 Dec 2002 00:46:56 -0500 (EST)
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. Dc usually however is clean in its transition and goes with out saying is battery backed up.
I'll add to that, that since DC removes the need for your own UPS's, by going with DC, you save rack space, deploy less gear (UPS's are HEAVY), and don't have to worry about which POPs have how many UPS's with dead batteries at any given time. OTOH, since with DC you're unlikely to have any backup power of your own, it is important to wire up both an A side and B side. Some places (like certain telcos) like to briefly turn off parts of their DC power grids somewhat regularly. This makes gear with only one set of DC inputs rather annoying. 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? DC also avoids bulky AC power cords...and not only are the wires less bulky, but you'll likely cut them to the actual length needed. Since DC wiring is usually screwed down, they don't get bumped or accidentally pulled out of the outlets as often. ---------------------------------------------------------------------- Jon Lewis *jlewis () lewis org*| I route System Administrator | therefore you are Atlantic Net | _________ http://www.lewis.org/~jlewis/pgp for PGP public key_________
Current thread:
- DC power versus AC power ip dude (Dec 27)
- Re: DC power versus AC power Scott Granados (Dec 27)
- Re: DC power versus AC power jlewis (Dec 28)
- Re: DC power versus AC power Måns Nilsson (Dec 29)
- Re: DC power versus AC power jlewis (Dec 28)
- Re: DC power versus AC power Stephen Sprunk (Dec 28)
- Re: DC power versus AC power Wayne Bogan (Dec 29)
- Re: DC power versus AC power Stephen Sprunk (Dec 29)
- Re: DC power versus AC power Wayne Bogan (Dec 29)
- <Possible follow-ups>
- RE: DC power versus AC power Kuhtz, Christian (Dec 29)
- Re: DC power versus AC power Rubens Kuhl Jr. (Dec 29)
- Re: DC power versus AC power Michael Painter (Dec 29)
- Re: DC power versus AC power David Lesher (Dec 29)
- Re: DC power versus AC power Scott Granados (Dec 29)
- Re: DC power versus AC power Charles Sprickman (Dec 29)
- Re: DC power versus AC power Scott Granados (Dec 27)