[114839] in North American Network Operators' Group
RE: Why choose 120 volts?
daemon@ATHENA.MIT.EDU (Dave Larter)
Wed May 27 18:40:17 2009
Date: Wed, 27 May 2009 18:39:37 -0400
In-Reply-To: <alpine.BSF.2.00.0905271823500.848@murf.icantclick.org>
From: "Dave Larter" <dave@stayonline.com>
To: "david raistrick" <drais@icantclick.org>,
"Seth Mattinen" <sethm@rollernet.us>
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
The ground is not supposed to carry any current where as the neutral is.
If you tried to carry current on the ground of a CGFI protected circuit
it would trip.=20
-----Original Message-----
From: david raistrick [mailto:drais@icantclick.org]=20
Sent: Wednesday, May 27, 2009 6:30 PM
To: Seth Mattinen
Cc: nanog@nanog.org
Subject: Re: Why choose 120 volts?
On Wed, 27 May 2009, Seth Mattinen wrote:
> Here's the L-G voltage off the 208v taps from an isolation transformer
in a=20
> system with no neutral: http://ninjamonkey.us/not_120_volts.jpg
Not 120, but 90 give or take. 90 is at the low end of the acceptable=20
range for common household 110/120v service.
Depending on how the phases are balanced in your facility, you may see=20
that fluctuate up or down, of course. If you measure hot to hot on the=20
same PDU, do you get anywhere close to 208? I'm going to suspect either
your fairly out of balance, or you've got a good bit of voltage drop by=20
the time it arrives....
But since the concensus from those who haven't used this is that the=20
device will present 208/240 at the 5-15 plug, I withdraw my suggestion
and=20
leave you to your own methods. (for the rest, test it yourself)
I also won't argue using ground for neutral, that's like arguing bonded
vs=20
unbonded panels.
---
david raistrick http://www.netmeister.org/news/learn2quote.html
drais@icantclick.org http://www.expita.com/nomime.html
