Re: Battery Boxes...What One Company Designed

[Marc F Hult <MFHult@xxxxxxxxxxxxxxxxxxxxx>]

On 19 Sep 2005 08:23:57 GMT, ddl@danlan.*com (Dan Lanciani) wrote in message
<1331589@xxxxxxxxxxxxxxxxxxx>:

>In article <jlpqi1pug6c0m8uiqalsq7hjeau43aqu44@xxxxxxx>,
MFHult@xxxxxxxxxxxxxxxxxxxxx (Marc F Hult) writes:
>| On 18 Sep 2005 05:13:37 GMT, ddl@danlan.*com (Dan Lanciani) wrote in message
>| <1331587@xxxxxxxxxxxxxxxxxxx>:
>|
>| >In article <ehopi1lk9nh29a8u247sbu1o1tt5cm65la@xxxxxxx>,
>| MFHult@xxxxxxxxxxxxxxxxxxxxx (Marc F Hult) writes:
>| >| On 18 Sep 2005 02:52:12 GMT, ddl@danlan.*com (Dan Lanciani) wrote in
message
>| >| <1331585@xxxxxxxxxxxxxxxxxxx>:
>| >|
>| >| >In article <as8pi1da45o1psehe0s983ql7439j8k3ek@xxxxxxx>,
>| >| MFHult@xxxxxxxxxxxxxxxxxxxxx (Marc F Hult) writes:
>| >|
>| >| >|
>| >| >|
>| >| >| Inteli-Power PD9180 and PD9160 (now Progressive Dynamics) as I wrote in
my
>| >| >| previous post. See
>| >| >|
>| >| >| http://www.progressivedyn.com/power_converters.html
>| >| >
>| >| >Interesting.  I had no idea that you could get class 2 supplies with such
>| >| >high power output.  Maybe I'll have to reconsider my low-voltage
>| distribution
>| >| >analysis...
>| >| >
>| >|
>| >[...]
>| >| IMO, Key here is UL and internal transformer isolation. But I haven't
probed
>| to
>| >| see whether it is specifically UL for Class 2. I am satisfied that it
means
>| >| engineering needs.
>| >
>| >Hmm.  But if it isn't UL listed as a class 2 supply then it can't supply
class
>| >2 circuits.  Class 2 supplies have some pretty stringent requirements for
>| >current limiting (not just over current protection--source impedance is a
>| >consideration).  Last time I checked the most power allowed for a class 2
>| >supply in the lowest voltage range was 100VA.  (At higher voltages the power
>| >is reduced disproportionately IIRC.)
>|
>| Interesting.
>|
>| Thanks for the clarification about Class 2. I musta had at least NEC Class 2
and
>| Class I, Division 2 all jumbled up ;-)
>
>As in Class I hazardous locations?

and even maybe even NCAA Division 1 and 2 ;-)
>
>| It would appear that the listing for the PD91x0 devices is probably UL 458 ("
>| Chargers or charging functions incorporated into converter or inverters for
use
>| in recreational vehicles and boats, as covered by the Standard for Power
>| Converters/Inverters and Power Converter/Inverter Systems for Land Vehicles
and
>| Marine Crafts").
>|
>| For home use, they may need to be listed under UL 1012.  " These requirements
>| cover portable, stationary, and fixed power units having an input rating of
600
>| volts or less, direct- and alternating- current, with at least one output not
>| marked Class 2, and that are intended to be employed in ordinary locations in
>| accordance with the National Electrical Code, ANSI/NFPA 70." ) I dunno.
>
>Perhaps.  However, I just looked at the hookup instructions and it appears
>that the outputs are directly paralleled with the battery bank, i.e., whatever
>over-current protection the devices offer does not actually protect the load
>side.  That suggests that no matter the listing the output is going to have to
>be treated like the output of any other battery bank which can deliver very
>high current, requiring, e.g., (expensive) class T fuses.  And of course, the
>wiring at that point isn't even class 1.  (I used to think that it could be
>class 1 subpar (b) which goes to 600V with no power limitations, but that's
>for signaling/control only...)

Yes. See the ASCII circuit diagram in my previous post and at the end of this
one. which I think makes this clear. Over-current protection is included.

Where do I find out about class T fuses ? Searching the 2005 draft NEC came up
blank. Why do I need them? Plain old Square D QO circuit  breakers are UL'd to
60vdc.

>| Previously I identified four sections of the code that seem to pertain:
>|
>| Article 411 lighting  (isolated; <30 volts/42.4v peak); max 20 amp branch
>| circuit supply; max 25amp lighting circuit; Class 2 power source; not
grounded )
>|
>| Article 720  ( <50 volts; =>12AWG wiring; Article 240 overcurrent )
>|
>| Article 725.21 Class 1 ( <30 volts and <1000 volt-amp )
>|
>| Article 725 Class 2  (supplying or active converting <100 watts at =<30VAC or
>| =<60vdc )
>|
>| Power for telcomm equipment is yet another set of NEC provisions that may
>| pertain depending on what it being powered.
>|
>| Article 411 is not particularly useful because it appears to pertain to a
>| complete unit that is UL listed as a system. One can buy low voltage wiring
>| systems as a package that conform to 411 that use bare wires a few inches
from a
>| tall person's head. But if is unclear that one can substitute or fix anything
>| and still be compliant. Note the "Class 2 power source requirement" .
>
>411 didn't used to (as of the 1999 NEC) require a class 2 supply and was
>(according to the notes) intended to cover both interior and exterior
>(landscape) lighting.  The wiring could be extended through/in a wall but
>only by using Chapter 3 materials and methods.  So even then it didn't
>really buy you much.  If they have added a genuine class 2 supply requirement
>I would think that many of the existing landscape lighting transformers are
>now out of spec since even the multi-output ones typically exceeded 100VA on
>each output.  It may be that there is now a specific (and different) type
>of class 2 listing for such supplies that makes this all work out.  There
>is an unfortunate trend in this respect to make listings extremely application-
>specific, thus thwarting non-standard or unanticipated custom assemblies.

Right. ABIK, it has changed and become more restrictive/ less useful. That was
my point.

Outdoor wiring low-voltage wiring was separated in the 2002(?). I haven't
pursued what the draft 2005 has to say. but I didn't stumble across anything
that clarified how to get from one t'other or made life easier.

>| Article 720 is where I should have indicated that the DC _supply_ to my
>| low-voltage lighting dimmers fall. As practical matter, one uses conventional
(
>| Sect 1-4 ANSI/NFPA 70) wiring  but keeps these conductors out of conduits and
>| boxes that also contain 120/220 VAC. My DC dimmer panel is about 4 feet from
the
>| PD91x0  supplies so this is easy to do.
>|
>| Article 725.21 Class 1 (not 2  Thank you ;-) ) would seem to pertain to (in
my
>| case) to:
>|
>| 1) The distribution of power from the centrally-located DC lighting dimmers
>| (24vdc input, 0-12vdc output) to my commercial track lighting that is
UL-listed
>| for remote transformers.
>|
>| http://www.ipnlighting.com/faq/linear_faqs.htm
>|
>| Each dimmer is rated at 250 watts and has its own 20 amp breaker.
>|
>| 2) The distribution of power from the 12vdc supply (tap) of my system  (80 x
12
>| = 960 < 1000v-a) as 725.21 Class 1
>
>Here's the problem I had when I looked at the whole low-voltage DC distribution
>idea a while back.  Whether you classify your circuits under 720 or 725's
>class 1 you still have to use the same Chapter 3 materials and methods that
>you would use for line voltage circuits.  Plus you have to keep the two
>(or maybe all three) separate.  Plus you have to deal with non-standard
>(and thus more expensive) ancillary components like DC-rated switches and
>fuses.  Plus you have the inherent loss disadvantages of low voltage.  As
>far as I can tell, the only thing you gain under class 1 is the ability to
>use No. 16 and 18 conductors, not that I'd want to.  Am I missing something?
>

Yes and maybe not :-)

Yes, from the perspective that you are analyzing the benefits as if the
installation is something to be commercialized -- which it is not. There is no
reason why a personal endeavor ("hobby") has to be practical, or cost effective.
Most of what I see folks doing in comp.home.automation (and perhaps the
cross-posted NGs too) would not meet those criteria. Perhaps we need to start a
rec.home.automation ;-)

Yes, from social reality that in a system with multiple, distributed components
that require electrical power, the conventional approach of providing that
energy with Class 2 wallwarts quickly becomes untenable. Spousal factor -- the
answer to "Can I put three _more_ wall warts over here so that the open-close
and tilt drapery motors and the controller can be powered?"  is "No".  So what
to do ? One part of the answer is distributed DC power in my case.

Yes, examining the assertion that 120VAC is always standard and low-voltage is
non-standard. To the extent that many of my objectives stem from, and are
ultimately directed at environmental monitoring, 120 AC is very much the
non-standard, not low-voltage. When was the last time you saw a AC-powered pH or
conductance meter?  Or weather station? Or sampling pump, or ... My backyard is
750 feet of river front that we own and I monitor.

Yes, from the standpoint that you see "keeping lines separate" as a negative.
We separate AC lines one from another too. Why is this a problem? Why is it not
a design advantage to have independent systems?  I can rip everything I've
installed out and the house and household would go on jist fine, albeit with
diminution of smart/automation functionality and emergency and aesthetic aspects
of lighting.

Yes, from the difference that you see having to use Chapter 3 materials as a
problem, whereas I see it as the cheapest way to get materials in many cases
anyway. The power of Home Depotizing as it were ..

Yes, recognizing that I already have a large supply of components for DIY.
Sometimes I build things just to convert "parts" into "devices" (in the spirit
of rec.home.automation ;-)

Yes, from the fact that the "inherent loss disadvantages of low voltage" is
eliminated completely by proportional increase in the cross-sectional areas of
conductors. There are, of course, advantages to higher voltages. We converted
our house in Spain from 110 to 220 3-phase which made conductors embedded in
solid masonry walls much more useful. But that is not the situation in my US
home. I am installing new conductors, and don't have to retrofit. The house is
184 years old and this is at least the fifth energy/lighting infrastructure
(Candle/lamp; coal gas lighting; knob and tube electrical; 1983 Romex
remodeling; 21st century HA )

And maybe *not* ;-) because you have excellent analytical abilities and apply
them diligently to a confusing set of facts, boundary conditions, circumstances
and regulations in a way that is very helpful to others (too).

I _greatly_ appreciate you helpful comments. You've helped to clarify, organize
and correct much.

Regards ... Marc
Marc_F_Hult
www.ECOntrol.org


+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

On Sun, 18 Sep 2005 15:04:00 GMT, Marc F Hult <MFHult@xxxxxxxxxxxxxxxxxxxxx>
wrote in message  <jlpqi1pug6c0m8uiqalsq7hjeau43aqu44@xxxxxxx>:


In ASCII, continuing from previous diagram:


28vdc -+->Circuit Breaker--->Dimmer module--->12vdc track UL w/remote xfmr
       |    (Art. 720 + 240)     (Art 725.21 Class 1)
       |
       +->Circuit Breaker -------------> devices
       |             (Art. 720 + 240)
       |
       +---->  DC-DC converter ----+---> device
              (Art.725 Class 2)    +---> device ground

14vdc -+---->  DC-DC converter ----+---> device
       |       (Art.725 Class 2)   +---> device ground
       |
       +----------------------------> device(s)
              (Art 725.21 Class 1)

0 ----------------------------------> ground
           (Art. 720 and 725 class 1)

Not shown are low-voltage outdoor lighting or telecomm.