Author Topic: Rapid shut down - what do I need?  (Read 143 times)

Trukinbear

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Rapid shut down - what do I need?
« on: September 22, 2020, 01:48:01 PM »
Okay, I've just been informed that I've got to have a rapid shut down system for my off-grid solar installation.

I've looked at the Birdhouse, it seems relatively straightforward, and the battery shutdown module to go in my OG E-panel, which already has the quick trip on the main breaker it appears... so Birdhouse + battery shutdown module + armored cat-5 cable between the two.

What about the PV side? My system doesn't have combiner boxes, and I really don't want them. I've got one set (+ -) coming into the E-panel for each Classic 250 (2) from the two PV arrays. I looked at the MNLSOB for array level shutdown, but it isn't clear that it works with the Birdhouse. Also, I'm a might confused with two versions (600V. 1000V), but then it says voltage has to be controlled to 80V within the array, and 30V leaving the array. Wait, 30V? How does a 30V PV system work with a MidNite Classic on a 48V system... I thought I needed a minimum of 81V to give the MPPT sufficient overhead? You'd think with a degree in English and experience as a technical proofreader that I'd understand this better.

What is with 600V and 1000V AND 80V and 30V? Are 80V and 30V AFTER the shutdown, or what?

Will two 600V MNLSOB, an MNLSOB-T1-AC, an MNBDM, and a Birdhouse (plus the armored cable) constitute a complete Rapid Shutdown System? Do I need anything else? System overview in the signature.

Thanks for your help.
SMA Solar Sunny Island SI6048
JA Solar 330W 72 cell panels (18)
Classic 250 (2)
MODBUS/Canbus comm adaptor for Sunny Island
SMA-OG E-panel
WhizBang Jr
MNSPD300V (3)
Atkinson GSCM mini-i
Onan Quiet Diesel QD-8000
Monterey 986Ah 'Big Sur' 24-125-11 48V battery
Off the grid on the PNW coast

Trukinbear

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Re: Rapid shut down - what do I need?
« Reply #1 on: September 22, 2020, 03:49:02 PM »
Ok, I see from the product description found at a retailer (but not in your brochure) that the MNLSOB doesn't work with charge controllers, only with grid-tied inverters (I'm guessing you really mean AC coupled string inverters?). I guess that explains the Current Transformer. 80V and 12A - what kind of string is that anyway? I'm looking at the MPPT pulling the voltage down to around 99V, and somewhere around 30A on each string... but then I thought we were talking DC all along. Say what you will but MidNite Solar's product line is confusing.

So. I need a combiner box even if I don't have anything to combine? :-(

Is that right?
« Last Edit: September 22, 2020, 04:15:57 PM by Trukinbear »
SMA Solar Sunny Island SI6048
JA Solar 330W 72 cell panels (18)
Classic 250 (2)
MODBUS/Canbus comm adaptor for Sunny Island
SMA-OG E-panel
WhizBang Jr
MNSPD300V (3)
Atkinson GSCM mini-i
Onan Quiet Diesel QD-8000
Monterey 986Ah 'Big Sur' 24-125-11 48V battery
Off the grid on the PNW coast

Trukinbear

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Re: Rapid shut down - what do I need?
« Reply #2 on: September 22, 2020, 04:09:55 PM »
Yall make this harder than it needs to be. Let me see if I've got this right - the Shutoff boxes (according to rapidShutdown11x17_frontBack.pdf) ONLY works with TRANSFORMERLESS inverters? Geez, isn't there a way to make my system based around the SMA Sunny Island SI6048 comply with RSS requirements using MidNite Solar's stuff?
SMA Solar Sunny Island SI6048
JA Solar 330W 72 cell panels (18)
Classic 250 (2)
MODBUS/Canbus comm adaptor for Sunny Island
SMA-OG E-panel
WhizBang Jr
MNSPD300V (3)
Atkinson GSCM mini-i
Onan Quiet Diesel QD-8000
Monterey 986Ah 'Big Sur' 24-125-11 48V battery
Off the grid on the PNW coast

Trukinbear

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Re: Rapid shut down - what do I need?
« Reply #3 on: September 22, 2020, 04:52:17 PM »
NEC-2014 is what I need to meet.

I've got two 3x3 arrays on the roof that I need to shut off. I believe I understand the Birdhouse and battery disconnect module end.
Can someone point me in right product direction please?
The most economical solution would be appreciated as there isn't much left in me after all the stuff in my signature. :-)

Anybody?
SMA Solar Sunny Island SI6048
JA Solar 330W 72 cell panels (18)
Classic 250 (2)
MODBUS/Canbus comm adaptor for Sunny Island
SMA-OG E-panel
WhizBang Jr
MNSPD300V (3)
Atkinson GSCM mini-i
Onan Quiet Diesel QD-8000
Monterey 986Ah 'Big Sur' 24-125-11 48V battery
Off the grid on the PNW coast

Trukinbear

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Re: Rapid shut down - what do I need?
« Reply #4 on: September 22, 2020, 05:06:01 PM »
One of these?
MNSOB4X-4P-75A-PSB
SMA Solar Sunny Island SI6048
JA Solar 330W 72 cell panels (18)
Classic 250 (2)
MODBUS/Canbus comm adaptor for Sunny Island
SMA-OG E-panel
WhizBang Jr
MNSPD300V (3)
Atkinson GSCM mini-i
Onan Quiet Diesel QD-8000
Monterey 986Ah 'Big Sur' 24-125-11 48V battery
Off the grid on the PNW coast

Kent0

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Re: Rapid shut down - what do I need?
« Reply #5 on: September 22, 2020, 06:33:57 PM »
To shut down the PV array you could use the Tigo TS4-A-F with the Tigo transmitter - it is compatible with the Classic charge controller. Since it looks like you are shutting down the ac output of the system, an ac/dc adapter for the Tigo transmitter (as included with the transmitter kit) would also be shut down and the PV modules would all be disconnected (and in compliance with 2014 NEC 690.12).

By the way there is nothing in NEC 690.12 that requires the ac output of the inverter to be shut down. Your plan reviewer or inspector may have another code section in mind that allows that to be required, but if they are referring to 690.12, that claim is false and they don't know where the solar circuit ends.

Trukinbear

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Re: Rapid shut down - what do I need?
« Reply #6 on: September 23, 2020, 02:34:38 AM »
To shut down the PV array you could use the Tigo TS4-A-F with the Tigo transmitter - it is compatible with the Classic charge controller. Since it looks like you are shutting down the ac output of the system, an ac/dc adapter for the Tigo transmitter (as included with the transmitter kit) would also be shut down and the PV modules would all be disconnected (and in compliance with 2014 NEC 690.12).

Thanks, while what would amount to about the same amount of money as the MidNite Solar RSS systems I've seen, the thought of unmounting 18 panels on a roof about 6" wider all around than the array really makes this not doable - not unless I'm being threatened with condemnation or something. Those last panels were a b*tch to juggle around and get wired at about 50# each and taller than I am. And I am by myself...

Serously, MidNite Solar doesn't make RSS system components that work with a system based around their most popular charge controller? Color me confused.
SMA Solar Sunny Island SI6048
JA Solar 330W 72 cell panels (18)
Classic 250 (2)
MODBUS/Canbus comm adaptor for Sunny Island
SMA-OG E-panel
WhizBang Jr
MNSPD300V (3)
Atkinson GSCM mini-i
Onan Quiet Diesel QD-8000
Monterey 986Ah 'Big Sur' 24-125-11 48V battery
Off the grid on the PNW coast

Trukinbear

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Re: Rapid shut down - what do I need?
« Reply #7 on: September 23, 2020, 12:22:29 PM »
Bizarre! Do all of you guys just not have an RSS system, or none of you use the Classic charge controllers? Weird, probably another grand in MidNite solar equipment someone could sell me... I'm glad to see (I guess) that you don't need my business.
SMA Solar Sunny Island SI6048
JA Solar 330W 72 cell panels (18)
Classic 250 (2)
MODBUS/Canbus comm adaptor for Sunny Island
SMA-OG E-panel
WhizBang Jr
MNSPD300V (3)
Atkinson GSCM mini-i
Onan Quiet Diesel QD-8000
Monterey 986Ah 'Big Sur' 24-125-11 48V battery
Off the grid on the PNW coast

boB

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Re: Rapid shut down - what do I need?
« Reply #8 on: September 23, 2020, 01:36:19 PM »

We are working on RSS stuff and we do have an earlier system that works at a string level but that older system does not work so well on a modular (PV module) basis.

Also, the charge controller, whatever it is, in certain NEC jurisdictions has to discharge the input capacitor section of the CC within 30 seconds.

We are also working on a newer system that works on a modular basis for the newer  NEC version and states that have adopted the latest versions.  Some states are slow to adopt and enforce.  Some states have adopted a newer NEC but are not enforcing certain sections of that newer NEC version also.

BTW, as far as getting your business, this is a very difficult business to compete in and there is very little profit in these RSD/RSS products.  It all goes to the cheapest and lowest price the users can get away with.  There are very strict and difficult UL standards to comply with as well. 

Right now, TIGO is the only game in town and is suing companies to stay that way.  We will get there eventually but this stuff is not easy.  If it were, everybody would be doing it.

What year of NEC are you forced to work with ?  Maybe you don't need it (yet) ?

K7IQ

Trukinbear

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Re: Rapid shut down - what do I need?
« Reply #9 on: September 23, 2020, 02:02:33 PM »
Thanks for the response. Everything I've done/am doing is unpermitted thanks to an almost 4-year pissing match with the planning commission. The only way they can remove me from my long paid for and current with taxes property is to condemn me for safety reasons. A neighbor piped up and said I can expect a visit from the inspector now that my panels are visible (barely) from the street. I designed a building to mount them on with an idea that they wouldn't be visible from the street, and if they weren't on mounts (I forgot the 2" of the mounts) you wouldn't be able to see anything - as it is you can see the edge of the first row of panels. We're very rural and there is almost no solar in the county so I'm not sure the inspector will understand what he sees - I'd like for it to at least LOOK like I'm trying to comply. The counties website seems to mention NEC-2014 though what parts they're ga-ga for I don't know. I've met or exceeded every other building and electrical code so far... No idea what they're going to pull.

The Tigo is a non-starter for me - it took me 2-1/2 months working by myself to get the panels up there, and reversing the process (and renting another lift) will put me deep into our torrential rainy season. The reason I said I needed a rapid shut down system is the neighbor is volunteer fire and said they had been trained to look for a solar disconnect. Am I conflating two different things, a disconnect, and a rapid shutdown system?

What stops the MNSOB4X-4P-75A-PSB (+ birdhouse) from acting as an array level disconnect for my two arrays? I'm sure I'm missing something here.
« Last Edit: September 23, 2020, 02:07:44 PM by Trukinbear »
SMA Solar Sunny Island SI6048
JA Solar 330W 72 cell panels (18)
Classic 250 (2)
MODBUS/Canbus comm adaptor for Sunny Island
SMA-OG E-panel
WhizBang Jr
MNSPD300V (3)
Atkinson GSCM mini-i
Onan Quiet Diesel QD-8000
Monterey 986Ah 'Big Sur' 24-125-11 48V battery
Off the grid on the PNW coast