[RE-wrenches] NEC for Batteries < 60v ??
Ray
ray at solarray.com
Tue Oct 20 14:24:59 EDT 2020
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 offgridsolar at sti.net
> <mailto:offgridsolar at sti.net> text 209 813 0060*
>
> On Mon, 19 Oct 2020 22:33:03 -0700, Kent Osterberg
> <kent at 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 <ray at solarray.com
>>>> <mailto:ray at 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.burt at glbcc.com <mailto:glenn.burt at 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-bounces at lists.re-wrenches.org
>>>>> <mailto:re-wrenches-bounces at lists.re-wrenches.org>> On
>>>>> Behalf Of Ray
>>>>> Sent: Saturday, March 09, 2019 12:41 PM
>>>>> To: RE-wrenches <re-wrenches at lists.re-wrenches.org
>>>>> <mailto:re-wrenches at lists.re-wrenches.org>>
>>>>> Cc: Bill Brooks <billb at energy808.com
>>>>> <mailto:billb at energy808.com>>; Bill Brooks
>>>>> <billbrooks7 at yahoo.com <mailto:billbrooks7 at 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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