From: Alex Rubenstein <alex@corp.nac.net>
Date: Tue, 26 May 2009 15:43:20 -0400
> I have a pure curiosity question for the NANOG crowd here. If you run
> your facility/datacenter/cage/rack on 120 volts, why?
Because we are stupid.
> 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.
That makes you smarter than the average guy.
But, if we were really smart, we'd run at least 277, or maybe
347. Countless amounts of money would be saved on losses
(transformation), copper (smaller wire), and many other areas. Most of
the stuff we all run is already insulated for these voltage levels.
Even better would be all two pole 2 pole 480's or 2 pole 600's, then
we wouldn't need neutrals.
Oh, yeah! Nothing sounds like more fun than working in a room full of
480 or 600 delta. I LIKE neutrals. (Sort of like I like continuing to
have a functioning heart.)
> Even better would be all two pole 2 pole 480's or 2 pole 600's, then
> we wouldn't need neutrals.
Oh, yeah! Nothing sounds like more fun than working in a room full of
480 or 600 delta. I LIKE neutrals. (Sort of like I like continuing to
have a functioning heart.)
Oh, yeah! Nothing sounds like more fun than working in a room full of
480 or 600 delta. I LIKE neutrals. (Sort of like I like continuing to
have a functioning heart.)
Nobody said delta.
If you just run 7200vac into your 1u chinese made peecee servers, then you can eliminate the space use of the step-down transformer in the mechanical room.
Oh, c'mon people! We need to all think green here too. All you need is to locate it in the right spot on the planet and set up a big lightning rod. The first sustainable energy datacenter with no emissions!
I still have a couple of Ethernet cards for 10Base2, and cables. ^.^
Yes, if someone unplug or it is loosen in the middle/end, it will be fun.
I guess it's going to be another bagel/coffee time except network
support people.
Yes - think of all the nasty partial failure cases that can be eliminated -
each entire datacenter is either up or down. Much simpler!
Getting back to reality, I've watched more than one electrician do a
two-finger liveness test on a 120v circuit, and done it myself. 240v
HURTS, and I've not seen a pro finger it deliberately. But I haven't
actually asked.
Getting back to reality, I've watched more than one electrician do a
two-finger liveness test on a 120v circuit, and done it myself. 240v
HURTS, and I've not seen a pro finger it deliberately. But I haven't
actually asked.
During my residential electrical apprenticeship, one of the tricks of
the trade I learnt was a quick two finger test on 120, but never
anything higher than that.
That was years ago. I would never do anything of the sort intentionally
ever again, even on low voltage systems (my girlfriend is an
Occupational Health and Safety Officer, and she frowns on that sort of
thing
It really depends on your conductivity to ground ie what you are
standing on and the shoes you are wearing whether you will remain safe
by 'testing' for hotness on a circuit by touching it.
@120V, 1.2 mA is enough to tell you that the line is live. 15mA is the
let-go threshold, and 100mA can kill within a second. 200mA will pretty
much kill instantly.
Even at 120V on non-conductive ground, if you ever accidentally touched
the grounded box while touching the live wire, you will likely be dead
before the breaker trips.
I stop at licking the 9v batteries, intentionally, but I have been
burned by 50KV before. Just imagine the copper you could save by just
sending the energy thru the air, but then I guess the DC would sound and
look more like the death star.
