[RE-wrenches] Remote battery disconnects
Jerry Shafer
jerrysgarage01 at gmail.com
Mon Jan 30 14:08:32 PST 2023
Wrenches.
You might want to consider turning off the inverter as a solution to
turning off the batteries, we have this feature as part of our installs
with outback real simple then no chance of AC anywhere, Not going to pop a
CC, no chance of run on and it has passed every time. Just a thought that's
a safe solution. With Outback you just have to turn off the master nothing
else.
"Fun time in a crazy world"
On Mon, Jan 30, 2023, 7:58 AM Brian Mehalic via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:
> Hey folks - love the Code, hate it, don’t care about it or follow it: it
> doesn’t matter to me. But if you want to change it you have to realize it
> is a process with rules and procedures, and posting on this list that “the
> NEC” should immediately “issue a memo” to do what you want or change what
> you don’t like has ZERO effect.
>
> Brian
>
> On Jan 30, 2023, at 4:47 AM, Christopher Warfel via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
>
>
>
> I don't think the discussion has forked at all. A solution to this
> problem, and it is the best solution all things considered, including
> firefighter exposure to 10 ft of conductors that I have a hard time imaging
> them being exposed to, is for the NEC to issue a memo IMMEDIATELY
> indicating that this section of the code is no longer to be considered a
> requirement and that the next Code cycle will eliminate this requirement.
>
> The other solutions discussed would only work for a few configurations
> realistically and would introduce more danger. Chris
>
>
>
> On 1/29/2023 2:41 PM, William Miller via RE-wrenches wrote:
>
> James, Brian and others:
>
>
>
> Thank you all for the lively discussion. I am always interested in my
> colleague’s perspectives and this has been illuminating.
>
>
>
> It appears to me the discussion has forked: One topic is how to deal with
> the reality of the new code regarding a very narrow scenario: ESS inside of
> a residence. The other topic is: has the NEC evolved to be overly
> restrictive without factual basis?
>
>
>
> Regarding the first topic, it’s in black and white that we must provide
> battery disconnecting means for energy storage systems located in one or
> two family homes if the battery voltage exceeds 60 VDC. There are very few
> areas that do not adopt the NEC. If you install ESS you will eventually
> have to deal with this code requirement one way or another.
>
>
>
> Due to lax enforcement or unfamiliarity on the part of local building
> departments, some of you may be able to skirt this requirement. This is
> great until something happens. If your non-compliant installation causes a
> loss, you will end up in the defendants chair, not the building inspector.
>
>
>
> Here is how I approach these compliance conundrums: If I could argue the
> code does not apply or there is a good reason to waive the requirement; if
> the building official agrees; if I feel the installation is really and
> truly safe without meeting the requirement—only then could I proceed
> without the disconnect. Otherwise I am going to have to find a way to
> comply.
>
>
>
> As contractors, each of you makes those decisions every day: What is safe
> enough for my clients? If any of you think you know more than the people
> who write the codes, then install what you can get away with and keep your
> fingers crossed. I am not willing to live like that.
>
>
>
> Regarding the second topic: Are we being picked on by an overly
> scare-mongering NFPA?
>
>
>
> What is interesting here is that while most electrical codes are trying to
> prevent house fires, this particular section is trying to protect fire
> fighters after a fire starts (or an earthquake happens or a dump truck runs
> into your house, etc.).
>
>
>
> When California first adopted roof clearances for fire fighters, I got my
> feelings hurt because I was losing business and I did not understand what
> it takes to fight a house fire. I spoke with a few fire fighters and
> learned about roof and wall venting and how it is affected by prevailing
> winds. I came around to appreciate there is a real need for rooftop fire
> setbacks.
>
>
>
> It is self-evident why firefighters would not want to cut into a wall with
> a demo saw if there are energized, high amperage conductors in or on that
> wall. This code requirement for battery disconnecting means is
> fundamentally sensible. That ends the discussion for me.
>
>
>
> Oh, yeah, the charge controller blowing up thing: Does anyone have any
> factual data to share on this? Regardless of that, does it really matter
> if the charge controller is saved but the house burns down?
>
>
>
> The islanding thing: To be compliant, all ungrounded battery conductors
> need to be disconnected. This includes the charge controller circuit(s).
> With the charge controllers and inverters disconnected from the batteries
> and from each other there cannot be DC “islanding”.
>
>
>
> The house flooding thing: At the surface, it appears you have a choice of
> disasters: flood or fire. I submit that fire is more destructive (I don’t
> think many people have died from a ruptured water pipe). I don’t think it
> has to be either or: Find a way to provide emergency power to freeze
> protection devices with that disconnect waived or under key in cooperation
> with the fire department. This may mean the batteries need to remain
> connected. Put those leads in metal raceway and mark their locations from
> the outside. Work with building and fire officials. Limit your liability.
>
>
>
> Thanks again to all of you for the discussion. I know what I need to do.
>
>
>
> William Miller
>
>
>
> Miller Solar
>
> 17395 Oak Road, Atascadero, CA 93422
>
> 805-438-5600
>
> www.millersolar.com
>
> CA Lic. 773985
>
>
>
>
>
> *From:* James Jarvis [mailto:jj at aprsworld.com]
> *Sent:* Saturday, January 28, 2023 7:03 PM
> *To:* Brian Mehalic
> *Cc:* RE-wrenches; william at millersolar.com
> *Subject:* Re: [RE-wrenches] Remote battery disconnects
>
>
>
> Brian and William,
>
>
>
> With all due respect, I think your geographical location of California may
> be limiting in your understanding of the implications of local power
> security.
>
>
>
> Where I am in Minnesota and where I work in Alaska, loss of power and
> backup power can have very expensive consequences. When it is -30F outside
> and howling wind, buildings only have a matter of hours before their
> interiors will drop below freezing. A few hours after that pipes start to
> freeze and break. Pressurized water then starts to spray everywhere and
> then things can very quickly run into six-figure dollars amounts of damage.
> So one way of reducing this risk is by installing an ESS.
>
>
>
> Around here, prior to the latest NEC, we didn't have exterior disconnects
> available for anyone to shut off power. We still don't for businesses.
>
>
>
> My point is that NEC is mandating that there be zero security of a
> buildings electrical systems by requiring publicly accessible disconnects
> on backup systems. And if NEC wasn't so prescriptive, there could be
> slightly more secure alternatives such as a KNOXBOX or access controlled
> disconnects.
>
>
>
> William: I also disagree with your premise that you'll test the battery
> disconnect system after dark. That's not a test; that's just cheating. You
> had a knowledge person tell you that the MPPT controllers can and do blow
> up when they lose their voltage reference (battery) under load. And
> removing the battery from the circuit does allow the charge controllers to
> island with the inverter and DC loads and do other damage. I know of a
> telecom customer that had hundreds of thousands of dollars of damage when
> their battery became disconnected. If you are unwilling to test it at full
> load, I'd guess you know that the whole concept is a dumb idea.
>
>
> -James Jefferson Jarvis
> APRS World, LLC
> +1-507-454-2727
>
> http://www.aprsworld.com/
>
>
>
>
>
> On Sat, Jan 28, 2023 at 7:35 PM Brian Mehalic <brian at solarenergy.org>
> wrote:
>
> Every single house I’ve looked at in my town has a breaker panel with a
> main service disconnect on the outside of the house already. So in many
> cases we are well beyond worrying about someone “flicking your switch!”
>
>
>
> In fact, in addition to the emergency disconnect requirement for
> stationary standby batteries [480.7(B)] and ESS [706.15(B)] in one- and
> two-family dwellings, also added in 2020 was the requirement for an
> emergency disconnect for services on those same one- and two-family
> dwellings [230.85].
>
> Brian Mehalic
>
>
>
> On Jan 28, 2023, at 5:58 PM, James Jarvis via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
>
>
>
> It would be nice if the decision was up to the owner / occupant of the
> property. I, for one, do not want any random person to be able to turn off
> my house or business with the flick of a switch. I feel strongly that there
> is far too much fear mongering in NEC with relation to renewable energy.
>
>
> -James Jefferson Jarvis
> APRS World, LLC
> +1-507-454-2727
>
> http://www.aprsworld.com/
>
>
>
>
>
> On Sat, Jan 28, 2023 at 6:22 PM William Miller via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
>
> Esteemed wrenches:
>
>
>
> Well if my house is on fire and the entry of fire responders is delayed
> for lack of a disconnect, I choose having the disconnect. I can worry about
> the charge controllers later.
>
>
>
> Others may prioritize their charge controller over their homes…
>
>
>
> Put a cable-tie lock in the closed position to discourage kids from
> messing with it. Test it only after dark.
>
>
>
> William
>
>
>
> On Sat, Jan 28, 2023 at 2:32 PM William Bryce <
> wlbryce at pineridgeproducts.com> wrote:
>
> All
>
>
>
> One thing that no one is talking about is what happens to the MPPT charge
> controllers when the Battery Disconnect trips when the charge controllers
> are under full load.
>
> Many will blow up. Try turning off the battery breaker on a SolaArk when
> the charge controllers are maxed, and see if you get lucky.
>
>
>
> On Sat, Jan 28, 2023 at 3:27 PM William Miller via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
>
> Jeremy:
>
>
>
> Thanks for posting the code references for those that had never looked
> them up.
>
>
>
> Chris:
>
>
>
> What do you mean by “a disconnect for AC wiring, not specific to which or
> both panel types”?
>
>
>
> All:
>
>
>
> Code references are handy when receiving edicts from building officials,
> but not required, IMHO, for two reasons: The contractor should already be
> versed in the codes and, building departments can mandate their own
> requirements above and beyond the code.
>
>
>
> It may seem redundant to require an AC disconnect for premise wiring as
> well as a DC battery disconnect. In most cases if you disconnect the
> inverter from the batteries the AC power goes off. However if the
> generator is running at the time, some battery inverters can operate when
> disconnected from batteries. So to completely de-energize all components
> of an off-grid home you need to disconnect the generator and the battery
> leads.
>
>
>
> In this case the home is required to have fire sprinklers. There is
> pressure pump to provide flow to these fire sprinklers-- said pump being
> powered by the inverter/battery system. I am going to apply for a waiver
> to remove the DC disconnect requirement on the grounds that the pressure
> pump is essential fire suppression equipment. Instead I will propose to
> supply an AC disconnect (meeting all requirements for accessibility and
> marking) that will disconnect all premise wiring except the pressure pump.
>
>
>
> By the way, I will of course be trying to apply the logic that the voltage
> specification is for nominal battery voltage and this project having a
> nominal 48 volt bank does not require the battery disconnect.
>
>
>
> I will let the group know what response I receive. Regardless of how this
> works in this jurisdiction, I think these are both valid arguments worth
> trying in any jurisdiction requiring the battery disconnect. Some
> officials are amenable to dialog and negotiation and some are less so.
>
>
>
>
>
> William Miller
>
>
>
> Miller Solar
>
> 17395 Oak Road, Atascadero, CA 93422
>
> 805-438-5600
>
> www.millersolar.com
>
> CA Lic. 773985
>
>
>
>
>
> *From:* RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] *On
> Behalf Of *Jeremy Rodriguez via RE-wrenches
> *Sent:* Saturday, January 28, 2023 10:12 AM
> *To:* cwarfel at entech-engineering.com; RE-wrenches
> *Cc:* Jeremy Rodriguez
> *Subject:* Re: [RE-wrenches] Remote battery disconnects
>
>
>
>
>
> *2020 Code Language:*
>
> *480.7 DC Disconnect Methods.*
>
> *(A) Disconnecting Means.* *A disconnecting means shall be provided for
> all ungrounded conductors derived from a stationary battery system with a
> voltage over 60 volts dc. A disconnecting means shall be readily accessible
> and located within sight of the battery system.*
>
> *N** (B) Emergency Disconnect. **For one-family and two-family dwellings,
> a disconnecting means or its remote control for a stationary battery system
> shall be located at a readily accessible location outside the building for
> emergency use. The disconnect shall be labeled “EMERGENCY DISCONNECT”.*
>
> *N (C) Disconnection of Series Battery Circuits. **Battery circuits
> exceeding 240 volts dc nominal between conductors or to ground and subject
> to field servicing shall have provisions to disconnect the series-connected
> strings into segments not exceeding 240 volts dc nominal for maintenance by
> qualified persons. Non-load-break bolted or plug-in disconnects shall be
> permitted.*
>
>
>
> Jeremy Rodriguez
>
> Solar Installation / Design
>
> All Solar, Inc.
>
> 1453 M St.
>
> Penrose Colorado 81240
>
>
>
> Sent by Jeremy's iPhone. Sorry for typos and shorthand.
>
>
>
> On Jan 28, 2023, at 7:28 AM, Christopher Warfel via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
>
>
>
> Seems confusing that the AHJ is requiring a disconnect for AC wiring, not
> specific to which or both panel types, and then a dc disconnect with no
> code reference. Was trying to convey a reasonable, safe approach. A lot
> of bad information from fire department solar consultants making a lot of
> money fear mongering, which has led to this type of situation. Chris
>
> On 1/27/2023 3:35 PM, William Miller via RE-wrenches wrote:
>
> Glenn:
>
>
>
> As I wrote, a DC disconnect is required. Here is an excerpt from the Q&A
> with the building official:
>
>
>
> 4. Will you be requiring an external disconnect to disconnect the AC
> output of the inverter system from premise wiring?
>
> Yes, as required per 230.85
>
> 5. Will you be requiring an external disconnect to disconnect batteries
> from the inverters?
>
> Yes
>
>
>
> If the DC disconnect was not required I would not be wasting everyone’s
> time with my post. I try to be careful about that, researching on my own
> before posting and trying to make my questions very clear. I also try not
> to embarrass myself with dumb questions, but that does happen occasionally…
>
>
>
> William
>
>
>
> Miller Solar
>
> 17395 Oak Road, Atascadero, CA 93422
>
> 805-438-5600
>
> www.millersolar.com
>
> CA Lic. 773985
>
>
>
>
>
> *From:* RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] *On
> Behalf Of *Glenn Burt via RE-wrenches
> *Sent:* Friday, January 27, 2023 11:46 AM
> *To:* William Miller via RE-wrenches
> *Cc:* Glenn Burt
> *Subject:* Re: [RE-wrenches] Remote battery disconnects
>
>
>
> Does the AHJ really want the batteries disconnected from conductors, or
> does he really just want the inverters to stop operating and producing AC
> within the house?
>
> Obviously there is a big difference here and it may be changing as the
> code evolves.
>
>
>
> -Glenn
>
> Sent from my 'smart'phone, so please excuse typos and spelling errors.
>
>
>
> ------ Original message------
>
> *From: *William Miller via RE-wrenches
>
> *Date: *Fri, Jan 27, 2023 2:26 PM
>
> *To: *RE-wrenches;
>
> *Cc: *William Miller;
>
> *Subject:*[RE-wrenches] Remote battery disconnects
>
>
>
> Friends:
>
>
>
> We have a large-ish residential off-grid system install coming up. The
> AHJ has said they will require a remote battery disconnect. I suspect
> there will be fire sprinkler controls and a pressure pump that would become
> inoperable if this system were engaged. In this case we will apply for a
> waiver.
>
>
>
> The last time this was discussed here as far as I can find was October of
> 2020. At that time no one suggested any specific battery disconnect
> equipment.
>
>
>
> To further clarify my needs: There will be 4 or 5 Radian 8048 inverters
> (5 or 6 4/0 battery circuits, ~350A each) and two 175 amp PV recombiner
> outputs. That is 6 poles of high amperage DC disconnects.
>
>
>
> The battery array will be either a UnigyII VRLA or a lithium of a brand
> yet to be determined. In the case of lithium we will look for a system
> that can remotely enable a BMS shutdown. In the case of a VRLA lead-acid,
> we will not have that luxury.
>
>
>
> I have done some considerable research and have not found viable, high
> amperage, remotely activated shutdown equipment.
>
>
>
> I am wondering what hardware others may be using to achieve remote battery
> disconnecting in these types of cases..
>
>
>
> William
>
>
>
> Miller Solar
>
> 17395 Oak Road, Atascadero, CA 93422
>
> 805-438-5600
>
> www.millersolar.com
>
> CA Lic. 773985
>
>
>
>
>
>
>
> _______________________________________________
> List sponsored by Redwood Alliance
>
> Pay optional member dues here: http://re-wrenches.org
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Change listserver email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> There are two list archives for searching. When one doesn't work, try the
> other:
> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> http://www.re-wrenches.org/etiquette.htm
>
> Check out or update participant bios:
> http://www.members.re-wrenches.org
>
> --
>
>
> William Miller
> Miller Solar.com
> 895-438-5600
> www.millersolar.com
>
> _______________________________________________
> List sponsored by Redwood Alliance
>
> Pay optional member dues here: http://re-wrenches.org
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Change listserver email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> There are two list archives for searching. When one doesn't work, try the
> other:
> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> http://www.re-wrenches.org/etiquette.htm
>
> Check out or update participant bios:
> http://www.members.re-wrenches.org
>
> _______________________________________________
> List sponsored by Redwood Alliance
>
> Pay optional member dues here: http://re-wrenches.org
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Change listserver email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> There are two list archives for searching. When one doesn't work, try the
> other:
> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> http://www.re-wrenches.org/etiquette.htm
>
> Check out or update participant bios:
> http://www.members.re-wrenches.org
>
>
> _______________________________________________
> List sponsored by Redwood Alliance
>
> Pay optional member dues here: http://re-wrenches.org
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Change listserver email address & settings:http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> There are two list archives for searching. When one doesn't work, try the other:https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:http://www.re-wrenches.org/etiquette.htm
>
> Check out or update participant bios:http://www.members.re-wrenches.org
>
> --
> Christopher Warfel
> ENTECH Engineering, Inc.
> PO Box 871, Block Island, RI 02807
> 401-466-8978
> <http://entech-engineering.com>
>
> <http://entech-engineering.com>
>
>
> _______________________________________________
> List sponsored by Redwood Alliance
>
> Pay optional member dues here: http://re-wrenches.org
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Change listserver email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> There are two list archives for searching. When one doesn't work, try the
> other:
> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> http://www.re-wrenches.org/etiquette.htm
>
> Check out or update participant bios:
> http://www.members.re-wrenches.org
>
> _______________________________________________
> List sponsored by Redwood Alliance
>
> Pay optional member dues here: http://re-wrenches.org
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Change listserver email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> There are two list archives for searching. When one doesn't work, try the
> other:
> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> http://www.re-wrenches.org/etiquette.htm
>
> Check out or update participant bios:
> http://www.members.re-wrenches.org
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20230130/8a0bc5f9/attachment.htm>
More information about the RE-wrenches
mailing list