Why choose 120 volts?

Ronald Cotoni setient at gmail.com
Thu May 28 11:49:27 CDT 2009

I have some similar input.  At my company, we use both 120 and 208
volt depending on what servers we are putting in the racks.  We can
fill up every single rack to full capacity 100% of the time by using
energy efficient servers.  The fact that it is 120 volt or 208 volt
hardly matters on most machines except Xeon/Opeteron class systems.
We use a lot of Core 2 duo, Atom and Xeon Low Voltage processors.
This allows us higher density on the same power and makes 208 volt
mostly irrelevant.

On Thu, May 28, 2009 at 11:18 AM, William Pitcock
<nenolod at systeminplace.net> wrote:
> On Tue, 2009-05-26 at 12:39 -0700, Seth Mattinen wrote:
>> I have a pure curiosity question for the NANOG crowd here. If you run
>> your facility/datacenter/cage/rack on 120 volts, why?
> We are using 120V in our colocation spaces.
>> I've been running my facility at 208 for years because I can get away
>> with lower amperage circuits. I'm curious about the reasons for using
>> high-amp 120 volt circuits to drive racks of equipment instead of
>> low-amp 208 or 240 volt circuits.
> The reason why we are using 120V is because we have pre-existing
> equipment (such as PDUs) that only support 120V operation.  I believe
> our newer PDUs support 120/208/240, but do not have the time to
> investigate that, and we still have a couple of older APC units still in
> service.  Our servers don't really care which voltage we provide, most
> of the PSUs can determine 120 vs 240 automatically, even.
> Also, at least at Equinix Chicago, 120V service was cheaper when we
> colocated there.  I do not know if this is the same case at Steadfast in
> Chicago, and as far as I know, HE does not offer 208/240 service in
> their Fremont-2 facility.  I could be misinformed on that, though.
> --
> William Pitcock
> SystemInPlace - Simple Hosting Solutions
> 1-866-519-6149

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