Want to move to all 208V for server racks

Justin M. Streiner streiner at cluebyfour.org
Thu Dec 2 11:27:14 CST 2010

On Thu, 2 Dec 2010, Jay Ashworth wrote:

> No, I'm pretty sure he means "across the 2 high legs of a 120/208 3ph
> Wye service", and I'd never heard that idea suggested before.  I can see
> why it reduces the amount of copper you need to run, but it seems as if
> it would have compensating disadvantages, though I can't think precisely
> what they might be at the moment.

The only ones I can think of are relatively modest, such as needing 2-pole 
breakers or a pair of ganged single-pole breakers for each circuit, so a 
panelboard would only be able to support half as many 208V circuits as 
120V circuits.

That could translate into needing more panelboards, more/larger switchgear 
to feed those panelboards, etc, but you can plan for this up-front easily 
enough if this new construction or a re-fit of an existing space.

The panelboards we put in our DR site last year are quite large, so we 
have some room to grow, and we also used 3-phase PDUs with both 120V and 
208V receptacles, there are fewer individual circuits going out to each 


> ----- Original Message -----
>> From: "Ingo Flaschberger" <if at xip.at>
>> To: "Jay Nakamura" <zeusdadog at gmail.com>
>> Cc: "NANOG" <nanog at nanog.org>
>> Sent: Thursday, December 2, 2010 11:22:32 AM
>> Subject: Re: Want to move to all 208V for server racks
>> Dear Jay,
>>> I really want to move all newly installed internal and customer
>>> racks
>>> over to all 208v power instead of 120v. As far as I can remember, I
>>> can't remember any server/switch/router or any other equipment that
>>> didn't run on 208v AC. (Other than you may need a different cable)
>>> Anyone have any experience where some oddball equipment that
>>> couldn't
>>> do 208v and regret going 208v? We won't have any TDM or SONET
>>> equipment, all Ethernet switches, routers and servers. I have
>>> control
>>> over internal equipment but sometimes customers surprises you.
>> you mean 240V AC 50HZ and move from 120V 60Hz? (or also 50Hz)
>> you will need to check each device if it supports 240V, commonly the
>> specified power ratings are printed at a stricker on the device
>> itself.
>> Kind regards,
>> Ingo Flaschberger

More information about the NANOG mailing list