I agree, Ray. Shutting down the inverter's ac output and the PV array is
sufficient to make a battery based system about as safe as possible for
firefighters. That is probably what was wanted when the code was revised
to require an outside battery disconnect. Unfortunately, the local AHJ
may not see it that way. But if the AHJ will agree to it the remote
inverter shutdown is an easy way to go. I like the way Schneider has
implemented remote power off in the XW series, once the remote shut off
is tripped the inverter must be manually reset. I don't believe it is
done that way in the Outback inverters which leaves open the question:
can the power come back on if the remote off circuit is compromised.
Well, it can't if there is a remotely tripped breaker used as a disconnect.
The issue of security for outside disconnects will be a major problem
that the 2020 code has created. Its not just renewable energy systems in
that situation. All new utility services have the same requirement.
Anyone having a beef with their neighbor can shut off their power. Best
if you wait until they are on vacation...
Kent Osterberg
Blue Mountain Solar
On 10/20/2020 11:24 AM, Ray wrote:
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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