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RE: DC power versus AC power
From: Wayne Bogan [mailto:[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 breakers in the invertor. 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 their canny ability to catch fire when the price is right. Inverters or rectifiers should be point solutions in a plant layout. If you have a lot of AC & DC, get two protected plants. Only way to live. Sometimes that's not just nice to have, but simply required. If you're primarily a systems shop and have environmentally conditioned space, get AC. If you're in a nasty colo spot, with poor environmental (read: not guaranteed meat locker climate 24x7), get DC & NEBS hardware or hardware which meets NEBS almost entirely but doesn't carry the sticker for some silly reason such as "easily flammable plastic used for front grill". Depending on what your colo requires. There are many different flavors of colo. Speaking of flavors, consider the impact of a turf vendor based on whatever decision you chose when going into colo space. May or may not be an issue. See what equipment offers what, do the math on cost of plant and gear, pros & cons. And make a business decision based on engineering data. (uh, right) 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). One of the biggest advantages is simplicity of design when it comes to battery plant. There is no universal answer, it all depends. And one ends up shuffling off and having to do a bunch of homework. 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: "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 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 of the argument depends on the facility you're in. Assuming you're > asking as an end-customer: > > DC requires clue from your staff when installing/removing equipment, and > this means safety training at a minimum. Power choice also affects your > equipment purchasing: DC versions of gear are often priced higher, and gear > not intended for telcos/ISPs may not have a DC option available at all. > > OTOH, many colos -- especially ones run by telcos -- don't provide AC UPS. > If you want AC UPS in these environments, you'll have to provide your own, > which is expensive, bulky, and a maintainance burden. > > If you're building your own datacenter, please specify that and I'm sure > you'll get a whole different discussion :) > > S > > ***** "The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential, proprietary, and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from all computers."