[j-nsp] 208v power and 110...

David B Funk dbfunk at engineering.uiowa.edu
Thu May 10 15:45:53 EDT 2018

> Date: Wed, 9 May 2018 14:26:13 -0700
> From: mike+jnsp at willitsonline.com
> To: juniper-nsp at puck.nether.net
> Subject: Re: [j-nsp] 208v power and 110...
> On 05/09/2018 10:52 AM, Scott Martin wrote:
> > Almost all equipment these days will run on 208V, in fact, everything
> > I've seen over the last ~10 years will auto switch from 100V - 240V
> > single phase 50/60Hz. (unless 208V is the minimum voltage, of course...)
> >
> > 208V is the way to go, imho. If you have high density racks, 8kVa or
> > larger, I'd go with 415V 3? which is 240V phase to neutral if that is
> > an option.
> Thanks (and to you other kind folks who replied). I feel a lot better
> now. Just didn't want to be stupid here and have wrong and dangerous
> ideas about how or what to do. No idea about the auto-switching but I
> guess that makes good sense (bad pun?).
> Mike-

Given that many places in the world have standard wall-outlet voltage of 
230-240, most manufacturers support higher voltage.

In the really old days you had to spec the appropriate PS for the voltage in 
your target area. In the not-so-old days there was a little switch on the back 
of the PS that selected 115/230 volts input range.

For almost everything these days the additional cost of the auto-sensing 
switching circuitry is at parity with the cost of the mechanical switch and the 
improvement in customer satisfaction makes it the clear win.
(customer neglects to set switch, plugs it in, magic smoke escapes, customer is 
unhappy ;).

auto-sensing is pretty ubiquitous, you'll find it in many consumer devices such 
as the wall-wart for charging your phone/PDAs.

Look at the power input rating label on a device, if it says "100-240" 
then it's auto-sensing and you're good to go.

Dave Funk                                  University of Iowa
<dbfunk (at) engineering.uiowa.edu>        College of Engineering
319/335-5751   FAX: 319/384-0549           1256 Seamans Center
Sys_admin/Postmaster/cell_admin            Iowa City, IA 52242-1527
#include <std_disclaimer.h>
Better is not better, 'standard' is better. B{

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