Interesting idea: shutting down the inverter should actually be
preferable to a battery disco, since its possible to disconnect the
battery and still have an inverter operate array direct if the loads are
close to the array output. I've seen it take several minutes for the
inverter to shut off sometimes.
This whole concept needs to be left in the oven longer to get the
verbage right. I believe the idea is to have power off to the
distribution circuits in the house, but NEC is having a really hard time
just saying that. Who cares if the battery is still connected to the
inverter; there will always be a few feet of battery cable energized,
regardless of the remote disconnect scheme. Seems much easier to shut
down the inverter, and then have a clause covering DC distribution for
those Luddites still doing that.
Overall, I have severe misgivings about this whole idea. While it
sounds good at first, you must consider that a failure of the remote
system, or a wacky neighbor can shut off the entire house including
refrigeration and heat. The customer could come back to rotten food and
frozen pipes. We need to have a more holistic approach that balances
fire fighter safety with home owner safety. Article 445 Generators,
exempts generators under 15 kW. It seems something similar for off grid
would be appropriate.
How many times has this actually been a problem? or is this possibly
just a high tech solution in search of an imagined problem?
Ray Walters
Remote Solar
303 505-8760
On 10/20/20 9:50 AM, Dave Angelini Offgrid Solar wrote:
Thanks Kent,
A question, most of the Sierra AHJ's only care, and that is rare, that
there is a remote power off like Outback and Schneider have already. I
understand it is not a battery disco, and even though there is one in
these systems, what is your response please?
I mostly dislike power sheds as people need an excuse to go there and
observe. I mostly use a garage or outside house wall to build a bat
room. Appreciate your thoughts. Insurance issues are not as important
these days as many of us no longer can get itCry
*Dave Angelini Offgrid Solar "we go where powerlines don't"
http://members.sti.net/offgridsolar/ e-mail offgridso...@sti.net
<mailto:offgridso...@sti.net> text 209 813 0060*
On Mon, 19 Oct 2020 22:33:03 -0700, Kent Osterberg
<k...@coveoregon.com> wrote:
Ray,
Per NEC 480 batteries below 48 volts didn't need a readily accessible
disconnect within site of the batteries. That's unchanged in the 2020
Code, you don't have to have a readily accessible disconnect within
site of the batteries. That's a good thing considering the
environment near lead acid batteries. A disconnect switch still isn't
required in the 48-volt battery room.
Yes, if you put a 48-volt battery in a one or two-family dwelling, an
outside (remote) emergency disconnect is required. That is going to
be a pain that may add hundreds of dollars to the cost of small
off-grid systems. You might get away with a mushroom switch and a
24-volt tap on the batteries to activate a remote trip breaker. But
considering that it is a fire-safety related circuit it is probably
best to spend the money for the bird box.
At the very least 480.7(B) should make off-grid folks think about
using a power shed. The power shed is not a dwelling so 2020 NEC
480.7(B) doesn't apply.
Kent Osterberg
Blue Mountain Solar
On 10/19/2020 8:34 PM, Ray wrote:
I've used Blue Planet, so I guess I have used an actual UL listed
ESS, even though they don't include the charge controller or
inverter. I knew they were UL, but I double checked and it is the
UL 9540 standard mentioned in 706. So in this case, we could ignore
480, but are held to 706. Regardless of 480 or 706, both are
possibly requiring the outside remote disconnect. Besides Midnite's
remote trip breakers, and the dreaded Bird House, what other options
are there to meet this new requirement? Can the Blue Planet be
tripped remotely?
and still my initial question:
Under 480.7, are batteries below 60v still required to have the
remote disconnect? They are exempted from having a disconnect at
all in 480.7(A)......quite confusing.
Ray Walters
Remote Solar
303 505-8760
On 10/19/20 7:06 PM, Jerry Shafer wrote:
Wrenches
Blue planet are fire and UL listed systems both on there 48 Volt
and the LX flavors
Jerry
On Mon, Oct 19, 2020, 5:51 PM Ray <r...@solarray.com
<mailto:r...@solarray.com>> wrote:
The notes in the NEC 2020 Handbook for article 706 clearly
state that 706 only covers ESS which is an assembly of
components, and that the total assembly must be listed under UL
9540.
Further it states: "/A group of separate components that
includes storage batteries, that is provided with support
systems (racks), charge controllers, and inverters, and that
does NOT have an overall listing as an ESS is a storage battery
system and as such is subject to the requirements of article 480"/
and just in case someone says the notes don't matter, 706.5
says: "/Energy Storage systems shall be listed"/.
So, since I have never used an actual listed ESS, I'm back to
480. Specifically, 480.7 (A) says we need a disconnect for
batteries over 60 vdc (48v should be exempt) and then 480.7(B)
says houses need to have an outside disconnect for the
batteries labeled "Emergency Disconnect".
So here's the real question: Does 480.7(A) exempt us from
480.7(B)?
Ray Walters
Remote Solar
303 505-8760
On 3/9/19 8:08 PM, Brian Mehalic wrote:
Hi Glenn, I don't completely agree with your interpretation of
ESS systems and the application of Article 706. Yes, an ESS
/could/ provide 120/240 VAC (e.g. the Powerwall), but the
figures in Article 690 show three different configurations
where the output of the ESS is not AC, and where the ESS
disconnect comes before any power electronics (like a
multimode inverter, as shown in the AC and DC coupled systems)
or loads (as shown in the stand-alone system). Are those ESS
connected to other systems which utilize stored energy to
provide AC power? Yes, but the key is "connected to other
systems" - in many cases the ESS only provides DC. In fact
the definition of ESS clearly states this - it /can/ have AC
or DC output, and it /may/ include power electronics (but may
not).
My understanding is that the 60 volt limit (which is obviously
problematic in a world where 48 VDC batteries and ESS are very
common) was inserted in order to exempt other devices that
store energy (such as UPS, or battery backup in fire
alarms/exit signage/etc.) from the 706 requirements.
Cheers,
Brian Mehalic
NABCEP Certified Solar PV Installation Professional™ R031508-59
National Electrical Code® CMP-4 Member
(520) 204-6639
Solar Energy International
http://www.solarenergy.org
SEI Professional Services
http://www.seisolarpros.com <http://www.seisolarpros.com>
On Sat, Mar 9, 2019 at 4:07 PM Glenn Burt
<glenn.b...@glbcc.com <mailto:glenn.b...@glbcc.com>> wrote:
Hi Ray,
This is a conversation I have had some time ago with a
number of my fellow inspectors and code experts. When the
2017 NEC came out, I agreed with Mike Holt and Bill
Brooks' assessment that the new article was poorly written
and did not apply to most systems being installed today.
After much discussion through my Cadmus network of
authorities, it emerged that indeed 706 apples to the
typical residential systems.
So Energy Storage Systems (ESS) are the point of article
706, and I believe that the key point is that the SYSTEM
is generating AC voltage of 120VAC or 240VAC, making the
system fall under article 706.
Batteries themselves are minimally covered by NEC 480,
NFPA 1, and the IFC as applicable locally.
So, the bottom line is that the new article does cover the
work we do when systems provide or interface with 120VAC
or above (making the system operation exceeding the 60V AC
trigger).
My initial problem was believing that the article applied
to a component (the battery bank), and not the system (all
components taken together as a generator/storage system).
It is an easy misunderstanding to make.
Hope this helps!
-Glenn Burt
-----Original Message-----
From: RE-wrenches
<re-wrenches-boun...@lists.re-wrenches.org
<mailto:re-wrenches-boun...@lists.re-wrenches.org>> On
Behalf Of Ray
Sent: Saturday, March 09, 2019 12:41 PM
To: RE-wrenches <re-wrenches@lists.re-wrenches.org
<mailto:re-wrenches@lists.re-wrenches.org>>
Cc: Bill Brooks <bi...@energy808.com
<mailto:bi...@energy808.com>>; Bill Brooks
<billbroo...@yahoo.com <mailto:billbroo...@yahoo.com>>
Subject: [RE-wrenches] NEC for Batteries < 60v ??
Hi Everyone;
I'm updating all my verbage on plansets, and I just
realized that the newly created article 706 covering
Energy Storage Systems is only for Over 60 VDC (706.1)
Also article 480 for batteries only requires disconnecting
means over 60 VDC ?! (480.7). I'm not about to not have
a disconnect, so now that NEC pulled battery systems out
of 690, where do we go for guidance on normal battery
systems: 12, 24, 48 VDC?
Overall, I welcome most of the changes in NEC 2017, like
separating off grid systems into articles 706, and 710,
but it seems us off grid installers need some more
clarification.
Thanks,
--
Ray Walters
Remote Solar
303 505-8760
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