[RE-wrenches] Battery RSD

Tue Jul 29 10:06:50 PDT 2025

Friends:

As I see it there are three reasons to have this disconnecting means:

1. Section 705 Code requirement.
2. Disconnecting for service.
3. Rapid shutdown for first responders.

It would be ideal if batteries with BMS systems had contact-closure
triggered inhibit system. The capability is baked into the circuitry, I am
sure. This would be far superior to heavy duty DC knife switches. I am
discussing that with Deka for the Duration line.

For first responders I have argued that the batteries that ultimately power
fire alarms or fire pumps should not be disconnected, avoiding the
requirement for reason 3 above.

I suspect 100 amps may be an insufficient rating for your batteries if they
have 80 amp disconnects and there are more than one.

I would be arguing the breaker(s) on the inverter are sufficient. Is it
possible to provide a lock-out on that breaker?

Keep us posted. This could happen to any of us.

William Miller
Miller Solar.com
805-438-5600
www.millersolar.com

On Tue, Jul 29, 2025 at 9:24 AM MD Electric & Solar via RE-wrenches <
re-wrenches at lists.re-wrenches.org> 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
>
>
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