Posted by Jim Wilkins on June 21, 2010, 9:46 pm
> Jim Wilkins wrote:
> >>...
> > It's 1:00 AM here. The line is at 122 VAC. In the middle of the day it
> > might drop to 119 VAC.
> That's pretty good. It varies a lot more here. Our utility company
> must be saving more on the infrastructure.
> mike
I found one of these with supposedly bad batteries for $5:
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=
=557808&CatId=234
The batteries recovered to about half their nominal capacity after an
equalizing charge on a lab supply. They will never achieve that
capacity in inverter service since it is for a C/20 discharge rate.
It adjusts the output voltage in steps if the AC input goes out of
limits. The power here is either on or off so I haven't tested that
too much. Now that I think of it, that is a useful feature to use with
my poorly regulated generators.
It recharges quickly, most of the way in two hours, so it's more
practical than the usual UPS to recharge on a portable generator.
jsw
Posted by Jim Wilkins on June 20, 2010, 12:14 am
> Interesting. Can you explain further?
> I was informed (where I can't remeber..or thought) the concept In Canada was
> that the neutral could be livened to ground (an it always is with load) and
> it could backfeed the grid and be transformed up to higher voltages.
> ...
> From a dim memory of back when I was supposed to know that stuff, the
> difference is whether or not the code assumes that hot and neutral
> might be swapped.
> jsw
That's in the department of don't even try to memorize this, always
look it up.
The issue was the legality of a double pole circuit breaker, whether
on single phase it could open both H and N or not. IIRC one side said
no, if the breaker fails you could have hot but no return which must
be hardwired, the other said yes, that either could be hot from
miswiring so opening both was safer. Pick your more probable failure
mode. That was around 1980 anyway, many revisions ago.
jsw
Posted by Josepi on June 20, 2010, 1:35 am
LOL I hear ya'
I took code syudy courses years ago but spent more time studying the new
version when I wired my home a few years ago. Wghen you are involved on a
continuous basis you roll with the updates but not being involved for a
while and the book changes... The bastards even changed all the paragraph
numbers somewhat.
When I installed my workshop/barn subpanel I forgot to run a separate
neutral underground to the first junction box. I figured the two ground rod
right outside the side wall would be good for equipotential grounding for
that building...case grounds, only. Two fill-in inspectors came to look at
it, in various stages and I ran the ground rods to the distribution part of
the panel, not the incoming. Knowing that grounds had to be continuous and
it wouldn't reach the neutral incoming, I figured I was in for a dig. The
first two inspectors told me it had to go into the top with the
neutral...yuk! (sweat! sweat!)
On the final inspection the local Inspector was back and asked me if I
removed the bonding screw (connects the neutral bar to the case with ground.
"Yup".
"Good. You can't connect a second groound point to the neutral!"
Every Inspector has his own delusions about grounding. I know being in the
utility field for 35 years, grounding is poorly understood, especially in
sensitive areas, like high voltage transmission and electronic signal lines.
The well pump sleeve was another story...LOL
That's in the department of don't even try to memorize this, always
look it up.
The issue was the legality of a double pole circuit breaker, whether
on single phase it could open both H and N or not. IIRC one side said
no, if the breaker fails you could have hot but no return which must
be hardwired, the other said yes, that either could be hot from
miswiring so opening both was safer. Pick your more probable failure
mode. That was around 1980 anyway, many revisions ago.
jsw
> >>...
> > It's 1:00 AM here. The line is at 122 VAC. In the middle of the day it
> > might drop to 119 VAC.
> That's pretty good. It varies a lot more here. Our utility company
> must be saving more on the infrastructure.
> mike