[RE-wrenches] Battery RSD

Tue Jul 29 14:45:01 PDT 2025

The problem I see with just complying is that there is really no practical
or cost-effective way to comply. You would have to somehow transition from
battery cable to some other cable type, because typical fusible disconnect
switch lugs are not going to be rated to accept
fine-stranded battery cable, especially in the required size.

Bozo is right. I wouldn't let that circus survive in my town.

Jason Szumlanski
Principal Solar Designer | Florida Solar Design Group
NABCEP Certified Solar Professional (PVIP)
Florida State Certified Solar Contractor CVC56956
Florida Certified Electrical Contractor EC13013208

On Tue, Jul 29, 2025 at 5:14 PM Dave Angelini Offgrid Solar via RE-wrenches
<re-wrenches at lists.re-wrenches.org> wrote:

> Things like this do happen sometimes. I do not have time for these and
> know it will not do much good most of the time.
>
> Do what the inspector (bozo) wants and fix it after he is gone.
>
>
>
> *Dave Angelini Offgrid Solar
> "we go where powerlines don't"
>    <http://members.sti.net/offgridsolar/>https://offgridsolar1.com/ <https://offgridsolar1.com/>  <http://members.sti.net/offgridsolar/>
> e-mail  offgridsolar at sti.net <offgridsolar at sti.net>
> text 209 813 0060*
>
>
> On 2025-07-29 2:02 pm, Jason Szumlanski via RE-wrenches wrote:
>
> Hold the phone! I would not let this become a precedent in a jurisdiction
> where I work. I'm not a CEC expert, but I'd fight this NEC question all the
> way to the state board in Florida. Here, the process would be to appeal to
> the Building Official, and if he is as clueless as the inspector, appeal to
> the Building Officials Association of Florida, which issues informal and
> formal rulings.
>
> An ESS is a SYSTEM. As defined (NEC 2020), it is "One or more components
> assembled together capable of storing energy and providing electrical
> energy into the premises wiring system or an electric power production and
> distribution network." The inspector is conflating a *battery* with an
> *ESS*. Technically, the Simpliphi "battery" is really a battery with a
> BMS, the combination of which *could* be an ESS if that were all there
> was to the system, but in this context, the battery and BMS are simply
> parts of a larger ESS.
>  A *battery* and BMS are just *components* of an ESS. There is a clear
> informational note in the NEC Handbook that includes inverters in what's
> included in an ESS. The typical understanding is that an ESS might
> include:
>
>    - Batteries
>    - Inverters
>    - Charge Controllers
>    - BMS (Battery Management System)
>    - Disconnects
>    - OCPD
>    - Monitoring hardware
>    - Enclosures
>
>
> The purpose of 706.2 is to provide a disconnect switch to isolate the
> *ESS* from the building wiring and parallel operated sources (i.e.
> utility). A simple AC disconnect on the output of the inverter
> should suffice in this case. It doesn't need to be a blade-type visible
> load breaker switch (unless your utility requires it and it can serve
> double duty). It could be as simple as a circuit breaker enclosure with a
> circuit breaker. You can get a combination of the two rated at 100A at the
> big orange store for $109. You probably already have a lockable disconnect
> on the inverter output anyway.
>
> This is one where I would fight rather than comply.
>
> Jason Szumlanski
> Principal Solar Designer | Florida Solar Design Group
> NABCEP Certified Solar Professional (PVIP)
> Florida State Certified Solar Contractor CVC56956
> Florida Certified Electrical Contractor EC13013208
>
> On Tue, Jul 29, 2025 at 4:13 PM david quattro via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
>
> 🤦🏻‍♂️ ugh these building departments..!  I'm very surprised that they're
> requiring the battery conductors to open. I don't think they understand the
> gravity of what they're saying
>
>
>
>
> On Tue, Jul 29, 2025 at 10:49 AM MD Electric & Solar <
> mdelectricsolar at gmail.com> wrote:
>
> David,
> We already have an RSD system installed, it shuts down the tigo's on the
> rooftop and it shuts down the AC output of the inverter, making the home
> safe for firefighters. I can't imagine what an additional battery shut down
> could do for safety, at 48V DC nominal?
> But we must comply with the AHJ........
>
> I priced (online) an Eaton 100amp 600V DC rated knife switch NEMA 3R,
> $4000.00....ouch
>
> Mike
>
>
> On Tue, Jul 29, 2025 at 10:41 AM david quattro <david at quattrosolar.com>
> wrote:
>
> I use the SolArk 12v micro-circuit that triggers RSD.  hopefully that's
> all they're looking for, is to kill ESS and solar DC.   When using
> plunger-type, or single gang it's easy.   But when they require a knife
> blade style switch it's tricky (with SolArk and Midnite).  This is because
> in order to deenergize ESS/RSD you have to *complete* the micro circuit.
>    Eaton makes a Nema4 switch that can be turned upside down.   that puts
> the red handle on the left side, which is unusual but I've done it, and I
> don't think it violates any requirement.
>    otherwise you're stuck using an ice cube relay.  Initiating RSD is
> easy, but getting everything to turn back on is harder.   Feel free to call
> me if you want
>
>
>
>
> On Tue, Jul 29, 2025 at 9:46 AM MD Electric & Solar via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
>
> Wondering if Midnight solar makes something outdoor rated, with a typical
> 250ADC breaker, like this:
> Outdoor rated, lockable....
>
> https://www.midnitesolar.com/productPhoto.php?product_ID=76&productCat_ID=8&sortOrder=5&act=p
>
> On Tue, Jul 29, 2025 at 9:39 AM jay <jay.peltz at gmail.com> wrote:
>
> Maybe if you left the key on a chain to open the door, and placard with
> instructions on the outside that would work?
>
>
> On Jul 29, 2025, at 10:23 AM, MD Electric & Solar <
> mdelectricsolar at gmail.com> wrote:
>
> Correct, it does not have an external disconnect, but if you open the
> cover, each battery has it's own disconnect and the Sol-Ark has a battery
> disconnect.
> Looks like I'm in the market for a 100 amp rated outdoor, lockable DC
> rated knife switch.
> Mike
>
> On Tue, Jul 29, 2025 at 9:16 AM jay <jay.peltz at gmail.com> wrote:
>
> I had to look up that battery enclosure and if I understand correctly it
> does not have an external breaker/disconnect so yes the inspector is
> correct in the need for one if I understand.
>
> jay
>
>
>
>
>
> On Jul 29, 2025, at 10:09 AM, MD Electric & Solar <
> mdelectricsolar at gmail.com> wrote:
>
> Here is the reference, attached.
>
> On Tue, Jul 29, 2025 at 8:49 AM jay <jay.peltz at gmail.com> wrote:
>
> I'll let the code experts chime in, but I would ask for the code reference
> they are referring to.
>
> The only one I can think of has to do with if the batteries are on the
> other side of a wall.
>
>  Thats as clean an install as they come
>
> jay
>
>
>
> > On Jul 29, 2025, at 9:43 AM, MDElectricSolar <mdelectricsolar at gmail.com>
> wrote:
> >
> > <image0.jpeg>
> > Michael D Nelson
> > MD Electric & Solar, Inc.
> > 707-684-0064 mobile
> > 707-884-1862 office
> > www.mdelectricsolar.com
> > www.facebook.com/mdelectricandsolar
> >
> >
> >> On Jul 29, 2025, at 8:06 AM, Jay via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
> >>
> >> What is the layout of the equipment
> >>
> >> Are the batteries next to and therefore in sight of the inverter?
> >>
> >> Jay
> >>
> >>> On Jul 29, 2025, at 8:44 AM, MDElectricSolar via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
> >>>
> >>> Wrenches,
> >>> I have a building inspector in my county of Sonoma who has just told
> me that we need to install a rapid shutdown switch of some type between my
> LFZ battery bank and my Solark 15k inverter. He mentioned some type of
> knife switch within 5 feet of the equipment. I cannot find any reference to
> this requirement anywhere but he insists it is required. These batteries
> happen to be simplify or brakes and Stratton batteries and each battery has
> its own 80 amp breaker on the battery and the Solark has a battery
> disconnect switch built-in. We do have module level RSD which kills the
> solar output as well as the inverter output when the button is pushed. Does
> anyone have any experience with this or can they point me to the correct
> code section or what are others doing to comply with this requirement?
> >>>
> >>>
> >>> Michael D Nelson
> >>> MD Electric & Solar, Inc.
> >>> 707-684-0064 mobile
> >>> 707-884-1862 office
> >>> www.mdelectricsolar.com
> >>> www.facebook.com/mdelectricandsolar
> >>>
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>
> --
> Michael D Nelson
> MD Electric & Solar Inc.
> Office: 707-412-3181
> Cell: 707-684-0064
> www.mdelectricsolar.com
> www.facebook.com/mdelectricandsolar
>
>
> <PRMD BLD_20250728_062230.pdf>
>
>
>
> --
> Michael D Nelson
> MD Electric & Solar Inc.
> Office: 707-412-3181
> Cell: 707-684-0064
> www.mdelectricsolar.com
> www.facebook.com/mdelectricandsolar
>
>
>
>
>
> --
> Michael D Nelson
> MD Electric & Solar Inc.
> Office: 707-412-3181
> Cell: 707-684-0064
> www.mdelectricsolar.com
> www.facebook.com/mdelectricandsolar
>
>
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> --
> Michael D Nelson
> MD Electric & Solar Inc.
> Office: 707-412-3181
> Cell: 707-684-0064
> www.mdelectricsolar.com
> www.facebook.com/mdelectricandsolar
>
>
>
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