Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[Jeff Clearwater]

<mailto:re-wrenches@lists.re-wrenches.org>

*Subject:* Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

 Ground mounts do NOT require RSS.  We hashed this out years ago on 
the Wrenches list, when NEC 2017 came out.


See Figure 690.1(B) Note (2): /" The PV system disconnect in these 
diagrams separates the PV system from all other systems"./


Thus, the PV disconnect is defined as the transition point from the PV 
system to all other systems, like battery or inverter systems. The 
installer/ designer decides where to put that disconnect.  I usually 
put it on the wall before it goes into the building, and I have never 
had an inspector question that.


Thanks,

Ray Walters
Remote Solar
303 505-8760

On 2/1/22 10:06 AM, William Miller wrote:



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Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[Brian Mehalic]

Of course you can put rapid shutdown in whatever circuits you want. You only 
have to put them on those PV DC circuits that are on or in building. If the 
conclusion is that “some number less than 100% of the DC circuits are on a 
building thus 100% of them need RS” it won’t be a code violation, but that 
doesn’t make it right/necessary. 

Brian

> On Feb 2, 2022, at 12:27 AM, William Miller  wrote:
> 
> 
> Friends:
>  
> One of my favorite things about this list-service:  The minute I think I have 
> posted something really stupid, someone agrees with me.  What a self-esteem 
> builder!  Thanks, Bradley!
>  
> Here are two conclusions I think I am arriving at with this discussion:
>  
> 1.   The language in the 2017 NEC is pretty vague on the issue.  Hopefully 
> this improves over time.
> 
> 2.   The point is really open to interpretation.  If you can convince your 
> building department that RSS is not required on a ground mount array, I think 
> it is entirely safe to omit the RSS.  This is a reasonable case to make if 
> one goes on the assumption the intent is to protect firefighters on roofs.
> 
> Thanks for the lively discussion.  The points we are all thoughtfully 
> presented.
>  
> William
>  
> Miller Solar
> 17395 Oak Road, Atascadero, CA 93422
> 805-438-5600
> www.millersolar.com
> CA Lic. 773985
>  
>  
> From: Bradley Bassett [mailto:bbasse...@gmail.com] 
> Sent: Tuesday, February 1, 2022 2:15 PM
> To: RE-wrenches
> Cc: William Miller
> Subject: Re: [RE-wrenches] Rapid Shutdown for Off-grid systems
>  
> "A switch, outside of the building, opening the PV circuit to the power 
> electronics, and functioning as the pv system disco and the rapid shutdown 
> initiation device, should be all that is required."
>  
> That is what I have found most inspectors will accept, but not all. A strict 
> reading of the code does come to the same conclusion that William comes to, 
> and some inspectors will require that. The code is not very specific on where 
> the PV system disconnect should go. It seems to be mostly accepted to be on 
> the PV side of the charge control, but when I read the code strictly it seems 
> to me it should be on the battery side of the charge control since it is only 
> a PV device. Fortunately the PV side is more accepted because that makes 
> things much easier. 
>  
> What I'm still having trouble with is the requirement for breaking both pos 
> and neg legs in the PV system disconnect unless solidly grounded which most 
> systems are not (690.13(E)). I see that most installers do not break both 
> poles, but only the positive leg, which is of course easier and less 
> expensive. I've quoted the use of dual pole breakers when possible, but 
> OutBack does not really call for that always, and if you ask about their 2 
> pole 300V breakers they (and Carling) don't say they can be used that way. 
> And if you do, you have to run the wires in opposite directions for polarity. 
> I've asked for clarification but have not received it yet. Then there are the 
> high voltage charge controls like Schneider, where often one uses the SqD 
> HU361, which can be wired in various ways to meet the 600V requirement. It 
> can be wired one pole for up to 18A Isc for PV, or up to 30A if two poles in 
> series, or one pos and one neg pole in the circuit. The Schneider RS Disco 
> does break both poles, one of the few devices that make it clear. I'm curious 
> what others are doing.
>  
> Brad
>  
> On Tue, Feb 1, 2022 at 11:23 AM Brian Mehalic  wrote:
> Sorry, forgot to state my previous comment was in regards to a ground-mount. 
> 
> Brian
> 
> 
> On Feb 1, 2022, at 12:19 PM, William Miller  wrote:
> 
> 
> Ray:
>  
> Thanks for that input.  I was hoping I was wrong.  I looked for that 
> discussion in the archives but could not find it.
>  
> William
>  
> Miller Solar
> 17395 Oak Road, Atascadero, CA 93422
> 805-438-5600
> www.millersolar.com
> CA Lic. 773985
>  
>  
> From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On 
> Behalf Of Ray
> Sent: Tuesday, February 1, 2022 10:11 AM
> To: re-wrenches@lists.re-wrenches.org
> Subject: Re: [RE-wrenches] Rapid Shutdown for Off-grid systems
>  
>  Ground mounts do NOT require RSS.  We hashed this out years ago on the 
> Wrenches list, when NEC 2017 came out.
> 
> See Figure 690.1(B) Note (2): " The PV system disconnect in these diagrams 
> separates the PV system from all other systems".
> 
> Thus, the PV disconnect is defined as the transition point from the PV system 
> to all other systems, like battery or inverter systems. The installer/ 
> designer decides where to put that disconnect.  I

Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[William Miller]

Friends:



One of my favorite things about this list-service:  The minute I think I
have posted something really stupid, someone agrees with me.  What a
self-esteem builder!  Thanks, Bradley!



Here are two conclusions I think I am arriving at with this discussion:



1.   The language in the 2017 NEC is pretty vague on the issue.  Hopefully
this improves over time.

2.   The point is really open to interpretation.  If you can convince your
building department that RSS is not required on a ground mount array, I
think it is entirely safe to omit the RSS.  This is a reasonable case to
make if one goes on the assumption the intent is to protect firefighters on
roofs.

Thanks for the lively discussion.  The points we are all thoughtfully
presented.



William



Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com

CA Lic. 773985





*From:* Bradley Bassett [mailto:bbasse...@gmail.com]
*Sent:* Tuesday, February 1, 2022 2:15 PM
*To:* RE-wrenches
*Cc:* William Miller
*Subject:* Re: [RE-wrenches] Rapid Shutdown for Off-grid systems



"A switch, outside of the building, opening the PV circuit to the power
electronics, and functioning as the pv system disco and the rapid shutdown
initiation device, should be all that is required."



That is what I have found most inspectors will accept, but not all. A
strict reading of the code does come to the same conclusion that William
comes to, and some inspectors will require that. The code is not very
specific on where the PV system disconnect should go. It seems to be mostly
accepted to be on the PV side of the charge control, but when I read the
code strictly it seems to me it should be on the battery side of the charge
control since it is only a PV device. Fortunately the PV side is more
accepted because that makes things much easier.



What I'm still having trouble with is the requirement for breaking both pos
and neg legs in the PV system disconnect unless solidly grounded which most
systems are not (690.13(E)). I see that most installers do not break both
poles, but only the positive leg, which is of course easier and less
expensive. I've quoted the use of dual pole breakers when possible, but
OutBack does not really call for that always, and if you ask about their 2
pole 300V breakers they (and Carling) don't say they can be used that way.
And if you do, you have to run the wires in opposite directions for
polarity. I've asked for clarification but have not received it yet. Then
there are the high voltage charge controls like Schneider, where often one
uses the SqD HU361, which can be wired in various ways to meet the 600V
requirement. It can be wired one pole for up to 18A Isc for PV, or up to
30A if two poles in series, or one pos and one neg pole in the circuit. The
Schneider RS Disco does break both poles, one of the few devices that make
it clear. I'm curious what others are doing.



Brad



On Tue, Feb 1, 2022 at 11:23 AM Brian Mehalic  wrote:

Sorry, forgot to state my previous comment was in regards to a
ground-mount.

Brian



On Feb 1, 2022, at 12:19 PM, William Miller  wrote:



Ray:



Thanks for that input.  I was hoping I was wrong.  I looked for that
discussion in the archives but could not find it.



William



Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com

CA Lic. 773985





*From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On
Behalf Of *Ray
*Sent:* Tuesday, February 1, 2022 10:11 AM
*To:* re-wrenches@lists.re-wrenches.org
*Subject:* Re: [RE-wrenches] Rapid Shutdown for Off-grid systems



 Ground mounts do NOT require RSS.  We hashed this out years ago on the
Wrenches list, when NEC 2017 came out.

See Figure 690.1(B) Note (2): *" The PV system disconnect in these diagrams
separates the PV system from all other systems".*

Thus, the PV disconnect is defined as the transition point from the PV
system to all other systems, like battery or inverter systems. The
installer/ designer decides where to put that disconnect.  I usually put it
on the wall before it goes into the building, and I have never had an
inspector question that.

Thanks,

Ray Walters

Remote Solar

303 505-8760

On 2/1/22 10:06 AM, William Miller wrote:

Jay:



Here is the text from 2017:



*690.12 Rapid Shutdown of PV Systems on Buildings. PV*

*system circuits installed on or in buildings shall include a rapid*

*shutdown function to reduce shock hazard for emergency*

*responders in accordance with 690.12(A) through (D).*



*Exception: Ground mounted PV system circuits that enter buildings, of*

*which the sole purpose is to house PV system equipment, shall not be*

*required to comply with 690.12.*



The wording is interesting.  The requirement is directed at “PV system
circuits…”, not PV arrays.  The passage does not specify where the PV
feeding those circuits is located, it just addresses where the circuits
are, specifically “in or on a building.”

Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[Ray]

PV System Disconnect, not RSS

Ray Walters
Remote Solar
303 505-8760

On 2/1/22 7:04 PM, Jeremy Rodriguez wrote:
Just a rated disco at the ground mount?   Labeled as the rapid 
shutdown switch?

That’s  too simple!

In

Jeremy Rodriguez
Solar Installation / Design Expert
All Solar, Inc.
1453 M St
Penrose Colorado 81240

Sent by Jeremy's iPhone. Sorry for typos and shorthand.

On Feb 1, 2022, at 6:49 PM, Lloyd Hoffstatter 
 wrote:



We’ve used multi-pole rated disconnects at the array.
Best regards,
Lloyd

Lloyd Hoffstatter
Sunstruck Consulting

Get Outlook for iOS <https://aka.ms/o0ukef>

*From:* RE-wrenches  on 
behalf of Jeremy Rodriguez 

*Sent:* Tuesday, February 1, 2022 8:31:16 PM
*To:* RE-wrenches 
*Subject:* Re: [RE-wrenches] Rapid Shutdown for Off-grid systems
What about the PV circuits that leave the combiner and are ran on or 
in a building to the CC




Jeremy Rodriguez
Solar Installation / Design Expert
All Solar, Inc.
1453 M St
Penrose Colorado 81240

Sent by Jeremy's iPhone. Sorry for typos and shorthand.


On Feb 1, 2022, at 4:07 PM, Brian Mehalic  wrote:

 For a ground mount PV system with a DC combiner, the PV source 
circuits are not in or on a building so RS doesn’t apply to them. 
And the definition of a charge controller in Art. 100 is in its 
relationship to batteries/storage, not really the charging source - 
fundamentally it’s there to protect the storage/batteries, so it’s 
best considered part of that system, not the PV system (and over the 
last several cycles nearly all references to charge control/lers 
have been moved out of 690).






Brian

On Feb 1, 2022, at 3:15 PM, Bradley Bassett  
wrote:



"A switch, outside of the building, opening the PV circuit to the 
power electronics, and functioning as the pv system disco and the 
rapid shutdown initiation device, should be all that is required."


That is what I have found most inspectors will accept, but not all. 
A strict reading of the code does come to the same conclusion that 
William comes to, and some inspectors will require that. The code 
is not very specific on where the PV system disconnect should go. 
It seems to be mostly accepted to be on the PV side of the charge 
control, but when I read the code strictly it seems to me it should 
be on the battery side of the charge control since it is only a PV 
device. Fortunately the PV side is more accepted because that makes 
things much easier.


What I'm still having trouble with is the requirement for 
breaking both pos and neg legs in the PV system disconnect unless 
solidly grounded which most systems are not (690.13(E)). I see that 
most installers do not break both poles, but only the positive leg, 
which is of course easier and less expensive. I've quoted the use 
of dual pole breakers when possible, but OutBack does not really 
call for that always, and if you ask about their 2 pole 300V 
breakers they (and Carling) don't say they can be used that way. 
And if you do, you have to run the wires in opposite directions for 
polarity. I've asked for clarification but have not received it 
yet. Then there are the high voltage charge controls like 
Schneider, where often one uses the SqD HU361, which can be wired 
in various ways to meet the 600V requirement. It can be wired one 
pole for up to 18A Isc for PV, or up to 30A if two poles in series, 
or one pos and one neg pole in the circuit. The Schneider RS Disco 
does break both poles, one of the few devices that make it clear. 
I'm curious what others are doing.


Brad

On Tue, Feb 1, 2022 at 11:23 AM Brian Mehalic 
 wrote:


Sorry, forgot to state my previous comment was in regards to a
ground-mount.

Brian


On Feb 1, 2022, at 12:19 PM, William Miller
 wrote:



Ray:

Thanks for that input.  I was hoping I was wrong.  I looked
for that discussion in the archives but could not find it.

William

Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com <http://www.millersolar.com/>

CA Lic. 773985

*From:*RE-wrenches
[mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf
Of *Ray
*Sent:* Tuesday, February 1, 2022 10:11 AM
*To:* re-wrenches@lists.re-wrenches.org
    *Subject:* Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

 Ground mounts do NOT require RSS.  We hashed this out years
ago on the Wrenches list, when NEC 2017 came out.

See Figure 690.1(B) Note (2): /" The PV system disconnect in
these diagrams separates the PV system from all other systems"./

Thus, the PV disconnect is defined as the transition point
from the PV system to all other systems, like battery or
inverter systems. The installer/ designer decides where to put
that disconnect.  I usually put it on the wall before it goes
into the building, and I have never had an inspecto

Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[Jeremy Rodriguez]

Just a rated disco at the ground mount?   Labeled as the rapid shutdown switch?
That’s  too simple!

In

Jeremy Rodriguez
Solar Installation / Design Expert
All Solar, Inc.
1453 M St
Penrose Colorado 81240

Sent by Jeremy's iPhone. Sorry for typos and shorthand.

On Feb 1, 2022, at 6:49 PM, Lloyd Hoffstatter  
wrote:


We’ve used multi-pole rated disconnects at the array.
Best regards,
Lloyd

Lloyd Hoffstatter
Sunstruck Consulting

Get Outlook for iOS<https://aka.ms/o0ukef>

From: RE-wrenches  on behalf of 
Jeremy Rodriguez 
Sent: Tuesday, February 1, 2022 8:31:16 PM
To: RE-wrenches 
Subject: Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

What about the PV circuits that leave the combiner and are ran on or in a 
building to the CC



Jeremy Rodriguez
Solar Installation / Design Expert
All Solar, Inc.
1453 M St
Penrose Colorado 81240

Sent by Jeremy's iPhone. Sorry for typos and shorthand.

On Feb 1, 2022, at 4:07 PM, Brian Mehalic  wrote:

 For a ground mount PV system with a DC combiner, the PV source circuits are 
not in or on a building so RS doesn’t apply to them. And the definition of a 
charge controller in Art. 100 is in its relationship to batteries/storage, not 
really the charging source - fundamentally it’s there to protect the 
storage/batteries, so it’s best considered part of that system, not the PV 
system (and over the last several cycles nearly all references to charge 
control/lers have been moved out of 690).





Brian

On Feb 1, 2022, at 3:15 PM, Bradley Bassett  wrote:


"A switch, outside of the building, opening the PV circuit to the power 
electronics, and functioning as the pv system disco and the rapid shutdown 
initiation device, should be all that is required."

That is what I have found most inspectors will accept, but not all. A strict 
reading of the code does come to the same conclusion that William comes to, and 
some inspectors will require that. The code is not very specific on where the 
PV system disconnect should go. It seems to be mostly accepted to be on the PV 
side of the charge control, but when I read the code strictly it seems to me it 
should be on the battery side of the charge control since it is only a PV 
device. Fortunately the PV side is more accepted because that makes things much 
easier.

What I'm still having trouble with is the requirement for breaking both pos and 
neg legs in the PV system disconnect unless solidly grounded which most systems 
are not (690.13(E)). I see that most installers do not break both poles, but 
only the positive leg, which is of course easier and less expensive. I've 
quoted the use of dual pole breakers when possible, but OutBack does not really 
call for that always, and if you ask about their 2 pole 300V breakers they (and 
Carling) don't say they can be used that way. And if you do, you have to run 
the wires in opposite directions for polarity. I've asked for clarification but 
have not received it yet. Then there are the high voltage charge controls like 
Schneider, where often one uses the SqD HU361, which can be wired in various 
ways to meet the 600V requirement. It can be wired one pole for up to 18A Isc 
for PV, or up to 30A if two poles in series, or one pos and one neg pole in the 
circuit. The Schneider RS Disco does break both poles, one of the few devices 
that make it clear. I'm curious what others are doing.

Brad

On Tue, Feb 1, 2022 at 11:23 AM Brian Mehalic 
mailto:br...@solarenergy.org>> wrote:
Sorry, forgot to state my previous comment was in regards to a ground-mount.

Brian

On Feb 1, 2022, at 12:19 PM, William Miller 
mailto:will...@millersolar.com>> wrote:



Ray:



Thanks for that input.  I was hoping I was wrong.  I looked for that discussion 
in the archives but could not find it.



William



Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com<http://www.millersolar.com/>

CA Lic. 773985





From: RE-wrenches 
[mailto:re-wrenches-boun...@lists.re-wrenches.org<mailto:re-wrenches-boun...@lists.re-wrenches.org>]
 On Behalf Of Ray
Sent: Tuesday, February 1, 2022 10:11 AM
To: re-wrenches@lists.re-wrenches.org<mailto:re-wrenches@lists.re-wrenches.org>
Subject: Re: [RE-wrenches] Rapid Shutdown for Off-grid systems



 Ground mounts do NOT require RSS.  We hashed this out years ago on the 
Wrenches list, when NEC 2017 came out.

See Figure 690.1(B) Note (2): " The PV system disconnect in these diagrams 
separates the PV system from all other systems".

Thus, the PV disconnect is defined as the transition point from the PV system 
to all other systems, like battery or inverter systems. The installer/ designer 
decides where to put that disconnect.  I usually put it on the wall before it 
goes into the building, and I have never had an inspector question that.

Thanks,

Ray Walters

Remote Solar

303 505-8760

On 2/1/22 10:06 AM, William Miller wrote:

Jay:



He

Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[Lloyd Hoffstatter]

We’ve used multi-pole rated disconnects at the array.
Best regards,
Lloyd

Lloyd Hoffstatter
Sunstruck Consulting

Get Outlook for iOS<https://aka.ms/o0ukef>

From: RE-wrenches  on behalf of 
Jeremy Rodriguez 
Sent: Tuesday, February 1, 2022 8:31:16 PM
To: RE-wrenches 
Subject: Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

What about the PV circuits that leave the combiner and are ran on or in a 
building to the CC



Jeremy Rodriguez
Solar Installation / Design Expert
All Solar, Inc.
1453 M St
Penrose Colorado 81240

Sent by Jeremy's iPhone. Sorry for typos and shorthand.

On Feb 1, 2022, at 4:07 PM, Brian Mehalic  wrote:

 For a ground mount PV system with a DC combiner, the PV source circuits are 
not in or on a building so RS doesn’t apply to them. And the definition of a 
charge controller in Art. 100 is in its relationship to batteries/storage, not 
really the charging source - fundamentally it’s there to protect the 
storage/batteries, so it’s best considered part of that system, not the PV 
system (and over the last several cycles nearly all references to charge 
control/lers have been moved out of 690).





Brian

On Feb 1, 2022, at 3:15 PM, Bradley Bassett  wrote:


"A switch, outside of the building, opening the PV circuit to the power 
electronics, and functioning as the pv system disco and the rapid shutdown 
initiation device, should be all that is required."

That is what I have found most inspectors will accept, but not all. A strict 
reading of the code does come to the same conclusion that William comes to, and 
some inspectors will require that. The code is not very specific on where the 
PV system disconnect should go. It seems to be mostly accepted to be on the PV 
side of the charge control, but when I read the code strictly it seems to me it 
should be on the battery side of the charge control since it is only a PV 
device. Fortunately the PV side is more accepted because that makes things much 
easier.

What I'm still having trouble with is the requirement for breaking both pos and 
neg legs in the PV system disconnect unless solidly grounded which most systems 
are not (690.13(E)). I see that most installers do not break both poles, but 
only the positive leg, which is of course easier and less expensive. I've 
quoted the use of dual pole breakers when possible, but OutBack does not really 
call for that always, and if you ask about their 2 pole 300V breakers they (and 
Carling) don't say they can be used that way. And if you do, you have to run 
the wires in opposite directions for polarity. I've asked for clarification but 
have not received it yet. Then there are the high voltage charge controls like 
Schneider, where often one uses the SqD HU361, which can be wired in various 
ways to meet the 600V requirement. It can be wired one pole for up to 18A Isc 
for PV, or up to 30A if two poles in series, or one pos and one neg pole in the 
circuit. The Schneider RS Disco does break both poles, one of the few devices 
that make it clear. I'm curious what others are doing.

Brad

On Tue, Feb 1, 2022 at 11:23 AM Brian Mehalic 
mailto:br...@solarenergy.org>> wrote:
Sorry, forgot to state my previous comment was in regards to a ground-mount.

Brian

On Feb 1, 2022, at 12:19 PM, William Miller 
mailto:will...@millersolar.com>> wrote:



Ray:



Thanks for that input.  I was hoping I was wrong.  I looked for that discussion 
in the archives but could not find it.



William



Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com<http://www.millersolar.com/>

CA Lic. 773985





From: RE-wrenches 
[mailto:re-wrenches-boun...@lists.re-wrenches.org<mailto:re-wrenches-boun...@lists.re-wrenches.org>]
 On Behalf Of Ray
Sent: Tuesday, February 1, 2022 10:11 AM
To: re-wrenches@lists.re-wrenches.org<mailto:re-wrenches@lists.re-wrenches.org>
Subject: Re: [RE-wrenches] Rapid Shutdown for Off-grid systems



 Ground mounts do NOT require RSS.  We hashed this out years ago on the 
Wrenches list, when NEC 2017 came out.

See Figure 690.1(B) Note (2): " The PV system disconnect in these diagrams 
separates the PV system from all other systems".

Thus, the PV disconnect is defined as the transition point from the PV system 
to all other systems, like battery or inverter systems. The installer/ designer 
decides where to put that disconnect.  I usually put it on the wall before it 
goes into the building, and I have never had an inspector question that.

Thanks,

Ray Walters

Remote Solar

303 505-8760

On 2/1/22 10:06 AM, William Miller wrote:

Jay:



Here is the text from 2017:



690.12 Rapid Shutdown of PV Systems on Buildings. PV

system circuits installed on or in buildings shall include a rapid

shutdown function to reduce shock hazard for emergency

responders in accordance with 690.12(A) through (D).



Exception: Ground mounted PV system circuits that enter bui

Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[Jeremy Rodriguez]

What about the PV circuits that leave the combiner and are ran on or in a 
building to the CC



Jeremy Rodriguez
Solar Installation / Design Expert
All Solar, Inc.
1453 M St
Penrose Colorado 81240

Sent by Jeremy's iPhone. Sorry for typos and shorthand.

On Feb 1, 2022, at 4:07 PM, Brian Mehalic  wrote:

 For a ground mount PV system with a DC combiner, the PV source circuits are 
not in or on a building so RS doesn’t apply to them. And the definition of a 
charge controller in Art. 100 is in its relationship to batteries/storage, not 
really the charging source - fundamentally it’s there to protect the 
storage/batteries, so it’s best considered part of that system, not the PV 
system (and over the last several cycles nearly all references to charge 
control/lers have been moved out of 690).





Brian

On Feb 1, 2022, at 3:15 PM, Bradley Bassett  wrote:


"A switch, outside of the building, opening the PV circuit to the power 
electronics, and functioning as the pv system disco and the rapid shutdown 
initiation device, should be all that is required."

That is what I have found most inspectors will accept, but not all. A strict 
reading of the code does come to the same conclusion that William comes to, and 
some inspectors will require that. The code is not very specific on where the 
PV system disconnect should go. It seems to be mostly accepted to be on the PV 
side of the charge control, but when I read the code strictly it seems to me it 
should be on the battery side of the charge control since it is only a PV 
device. Fortunately the PV side is more accepted because that makes things much 
easier.

What I'm still having trouble with is the requirement for breaking both pos and 
neg legs in the PV system disconnect unless solidly grounded which most systems 
are not (690.13(E)). I see that most installers do not break both poles, but 
only the positive leg, which is of course easier and less expensive. I've 
quoted the use of dual pole breakers when possible, but OutBack does not really 
call for that always, and if you ask about their 2 pole 300V breakers they (and 
Carling) don't say they can be used that way. And if you do, you have to run 
the wires in opposite directions for polarity. I've asked for clarification but 
have not received it yet. Then there are the high voltage charge controls like 
Schneider, where often one uses the SqD HU361, which can be wired in various 
ways to meet the 600V requirement. It can be wired one pole for up to 18A Isc 
for PV, or up to 30A if two poles in series, or one pos and one neg pole in the 
circuit. The Schneider RS Disco does break both poles, one of the few devices 
that make it clear. I'm curious what others are doing.

Brad

On Tue, Feb 1, 2022 at 11:23 AM Brian Mehalic 
mailto:br...@solarenergy.org>> wrote:
Sorry, forgot to state my previous comment was in regards to a ground-mount.

Brian

On Feb 1, 2022, at 12:19 PM, William Miller 
mailto:will...@millersolar.com>> wrote:


Ray:

Thanks for that input.  I was hoping I was wrong.  I looked for that discussion 
in the archives but could not find it.

William

Miller Solar
17395 Oak Road, Atascadero, CA 93422
805-438-5600
www.millersolar.com<http://www.millersolar.com/>
CA Lic. 773985


From: RE-wrenches 
[mailto:re-wrenches-boun...@lists.re-wrenches.org<mailto:re-wrenches-boun...@lists.re-wrenches.org>]
 On Behalf Of Ray
Sent: Tuesday, February 1, 2022 10:11 AM
To: re-wrenches@lists.re-wrenches.org<mailto:re-wrenches@lists.re-wrenches.org>
Subject: Re: [RE-wrenches] Rapid Shutdown for Off-grid systems


 Ground mounts do NOT require RSS.  We hashed this out years ago on the 
Wrenches list, when NEC 2017 came out.

See Figure 690.1(B) Note (2): " The PV system disconnect in these diagrams 
separates the PV system from all other systems".

Thus, the PV disconnect is defined as the transition point from the PV system 
to all other systems, like battery or inverter systems. The installer/ designer 
decides where to put that disconnect.  I usually put it on the wall before it 
goes into the building, and I have never had an inspector question that.

Thanks,

Ray Walters

Remote Solar

303 505-8760
On 2/1/22 10:06 AM, William Miller wrote:
Jay:

Here is the text from 2017:

690.12 Rapid Shutdown of PV Systems on Buildings. PV
system circuits installed on or in buildings shall include a rapid
shutdown function to reduce shock hazard for emergency
responders in accordance with 690.12(A) through (D).

Exception: Ground mounted PV system circuits that enter buildings, of
which the sole purpose is to house PV system equipment, shall not be
required to comply with 690.12.

The wording is interesting.  The requirement is directed at “PV system 
circuits…”, not PV arrays.  The passage does not specify where the PV feeding 
those circuits is located, it just addresses where the circuits are, 
specifically “in or on a building.”

The only circuits that are ex

Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[Brian Mehalic]

For a ground mount PV system with a DC combiner, the PV source circuits are not 
in or on a building so RS doesn’t apply to them. And the definition of a charge 
controller in Art. 100 is in its relationship to batteries/storage, not really 
the charging source - fundamentally it’s there to protect the 
storage/batteries, so it’s best considered part of that system, not the PV 
system (and over the last several cycles nearly all references to charge 
control/lers have been moved out of 690). 





Brian

> On Feb 1, 2022, at 3:15 PM, Bradley Bassett  wrote:
> 
> 
> "A switch, outside of the building, opening the PV circuit to the power 
> electronics, and functioning as the pv system disco and the rapid shutdown 
> initiation device, should be all that is required."
> 
> That is what I have found most inspectors will accept, but not all. A strict 
> reading of the code does come to the same conclusion that William comes to, 
> and some inspectors will require that. The code is not very specific on where 
> the PV system disconnect should go. It seems to be mostly accepted to be on 
> the PV side of the charge control, but when I read the code strictly it seems 
> to me it should be on the battery side of the charge control since it is only 
> a PV device. Fortunately the PV side is more accepted because that makes 
> things much easier. 
> 
> What I'm still having trouble with is the requirement for breaking both pos 
> and neg legs in the PV system disconnect unless solidly grounded which most 
> systems are not (690.13(E)). I see that most installers do not break both 
> poles, but only the positive leg, which is of course easier and less 
> expensive. I've quoted the use of dual pole breakers when possible, but 
> OutBack does not really call for that always, and if you ask about their 2 
> pole 300V breakers they (and Carling) don't say they can be used that way. 
> And if you do, you have to run the wires in opposite directions for polarity. 
> I've asked for clarification but have not received it yet. Then there are the 
> high voltage charge controls like Schneider, where often one uses the SqD 
> HU361, which can be wired in various ways to meet the 600V requirement. It 
> can be wired one pole for up to 18A Isc for PV, or up to 30A if two poles in 
> series, or one pos and one neg pole in the circuit. The Schneider RS Disco 
> does break both poles, one of the few devices that make it clear. I'm curious 
> what others are doing.
> 
> Brad
> 
>> On Tue, Feb 1, 2022 at 11:23 AM Brian Mehalic  wrote:
>> Sorry, forgot to state my previous comment was in regards to a ground-mount. 
>> 
>> Brian
>> 
>>>> On Feb 1, 2022, at 12:19 PM, William Miller  
>>>> wrote:
>>>> 
>>> 
>>> Ray:
>>> 
>>>  
>>> 
>>> Thanks for that input.  I was hoping I was wrong.  I looked for that 
>>> discussion in the archives but could not find it.
>>> 
>>>  
>>> 
>>> William
>>> 
>>>  
>>> 
>>> Miller Solar
>>> 
>>> 17395 Oak Road, Atascadero, CA 93422
>>> 
>>> 805-438-5600
>>> 
>>> www.millersolar.com
>>> 
>>> CA Lic. 773985
>>> 
>>>  
>>> 
>>>  
>>> 
>>> From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On 
>>> Behalf Of Ray
>>> Sent: Tuesday, February 1, 2022 10:11 AM
>>> To: re-wrenches@lists.re-wrenches.org
>>> Subject: Re: [RE-wrenches] Rapid Shutdown for Off-grid systems
>>> 
>>>  
>>> 
>>>  Ground mounts do NOT require RSS.  We hashed this out years ago on the 
>>> Wrenches list, when NEC 2017 came out.
>>> 
>>> See Figure 690.1(B) Note (2): " The PV system disconnect in these diagrams 
>>> separates the PV system from all other systems".
>>> 
>>> Thus, the PV disconnect is defined as the transition point from the PV 
>>> system to all other systems, like battery or inverter systems. The 
>>> installer/ designer decides where to put that disconnect.  I usually put it 
>>> on the wall before it goes into the building, and I have never had an 
>>> inspector question that.
>>> 
>>> Thanks,
>>> 
>>> Ray Walters
>>> Remote Solar
>>> 303 505-8760
>>> On 2/1/22 10:06 AM, William Miller wrote:
>>> 
>>> Jay:
>>> 
>>>  
>>> 
>>> Here is the text from 2017:
>>> 
>>>  
>>> 
>>> 690.12 Rapid Shutdown of PV Systems on Buildings. PV
>>> 
>>> sys

Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[Bradley Bassett]

"A switch, outside of the building, opening the PV circuit to the power
electronics, and functioning as the pv system disco and the rapid shutdown
initiation device, should be all that is required."

That is what I have found most inspectors will accept, but not all. A
strict reading of the code does come to the same conclusion that William
comes to, and some inspectors will require that. The code is not very
specific on where the PV system disconnect should go. It seems to be mostly
accepted to be on the PV side of the charge control, but when I read the
code strictly it seems to me it should be on the battery side of the charge
control since it is only a PV device. Fortunately the PV side is more
accepted because that makes things much easier.

What I'm still having trouble with is the requirement for breaking both pos
and neg legs in the PV system disconnect unless solidly grounded which most
systems are not (690.13(E)). I see that most installers do not break both
poles, but only the positive leg, which is of course easier and less
expensive. I've quoted the use of dual pole breakers when possible, but
OutBack does not really call for that always, and if you ask about their 2
pole 300V breakers they (and Carling) don't say they can be used that way.
And if you do, you have to run the wires in opposite directions for
polarity. I've asked for clarification but have not received it yet. Then
there are the high voltage charge controls like Schneider, where often one
uses the SqD HU361, which can be wired in various ways to meet the 600V
requirement. It can be wired one pole for up to 18A Isc for PV, or up to
30A if two poles in series, or one pos and one neg pole in the circuit. The
Schneider RS Disco does break both poles, one of the few devices that make
it clear. I'm curious what others are doing.

Brad

On Tue, Feb 1, 2022 at 11:23 AM Brian Mehalic  wrote:

> Sorry, forgot to state my previous comment was in regards to a
> ground-mount.
>
> Brian
>
> On Feb 1, 2022, at 12:19 PM, William Miller 
> wrote:
>
> 
>
> Ray:
>
>
>
> Thanks for that input.  I was hoping I was wrong.  I looked for that
> discussion in the archives but could not find it.
>
>
>
> William
>
>
>
> Miller Solar
>
> 17395 Oak Road, Atascadero, CA 93422
>
> 805-438-5600
>
> www.millersolar.com
>
> CA Lic. 773985
>
>
>
>
>
> *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On
> Behalf Of *Ray
> *Sent:* Tuesday, February 1, 2022 10:11 AM
> *To:* re-wrenches@lists.re-wrenches.org
> *Subject:* Re: [RE-wrenches] Rapid Shutdown for Off-grid systems
>
>
>
>  Ground mounts do NOT require RSS.  We hashed this out years ago on the
> Wrenches list, when NEC 2017 came out.
>
> See Figure 690.1(B) Note (2): *" The PV system disconnect in these
> diagrams separates the PV system from all other systems".*
>
> Thus, the PV disconnect is defined as the transition point from the PV
> system to all other systems, like battery or inverter systems. The
> installer/ designer decides where to put that disconnect.  I usually put it
> on the wall before it goes into the building, and I have never had an
> inspector question that.
>
> Thanks,
>
> Ray Walters
>
> Remote Solar
>
> 303 505-8760
>
> On 2/1/22 10:06 AM, William Miller wrote:
>
> Jay:
>
>
>
> Here is the text from 2017:
>
>
>
> *690.12 Rapid Shutdown of PV Systems on Buildings. PV*
>
> *system circuits installed on or in buildings shall include a rapid*
>
> *shutdown function to reduce shock hazard for emergency*
>
> *responders in accordance with 690.12(A) through (D).*
>
>
>
> *Exception: Ground mounted PV system circuits that enter buildings, of*
>
> *which the sole purpose is to house PV system equipment, shall not be*
>
> *required to comply with 690.12.*
>
>
>
> The wording is interesting.  The requirement is directed at “PV system
> circuits…”, not PV arrays.  The passage does not specify where the PV
> feeding those circuits is located, it just addresses where the circuits
> are, specifically “in or on a building.”
>
>
>
> The only circuits that are exempt are those feeding a building that serves
> only one purpose, to house PV equipment.  For circuits that enter building
> with other uses—homes, garages, barns, workshops, etc.-- it would seem
> there is a requirement to have rapid shutdown systems (RSS).
>
>
>
> Reading through the rest of the section, I don’t see any language that
> gets us out of the requirement to reduce voltages to less than 80 volts
> within 30 seconds inside the array boundary, as in module level shutdown,
> regardless of roof-top or ground-mount.  Although the 2020 code includes
> so

Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[Brian Mehalic]

Sorry, forgot to state my previous comment was in regards to a ground-mount. 

Brian

> On Feb 1, 2022, at 12:19 PM, William Miller  wrote:
> 
> 
> Ray:
>  
> Thanks for that input.  I was hoping I was wrong.  I looked for that 
> discussion in the archives but could not find it.
>  
> William
>  
> Miller Solar
> 17395 Oak Road, Atascadero, CA 93422
> 805-438-5600
> www.millersolar.com
> CA Lic. 773985
>  
>  
> From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On 
> Behalf Of Ray
> Sent: Tuesday, February 1, 2022 10:11 AM
> To: re-wrenches@lists.re-wrenches.org
> Subject: Re: [RE-wrenches] Rapid Shutdown for Off-grid systems
>  
>  Ground mounts do NOT require RSS.  We hashed this out years ago on the 
> Wrenches list, when NEC 2017 came out.
> 
> See Figure 690.1(B) Note (2): " The PV system disconnect in these diagrams 
> separates the PV system from all other systems".
> 
> Thus, the PV disconnect is defined as the transition point from the PV system 
> to all other systems, like battery or inverter systems. The installer/ 
> designer decides where to put that disconnect.  I usually put it on the wall 
> before it goes into the building, and I have never had an inspector question 
> that.
> 
> Thanks,
> 
> Ray Walters
> Remote Solar
> 303 505-8760
> On 2/1/22 10:06 AM, William Miller wrote:
> Jay:
>  
> Here is the text from 2017:
>  
> 690.12 Rapid Shutdown of PV Systems on Buildings. PV
> system circuits installed on or in buildings shall include a rapid
> shutdown function to reduce shock hazard for emergency
> responders in accordance with 690.12(A) through (D).
>  
> Exception: Ground mounted PV system circuits that enter buildings, of
> which the sole purpose is to house PV system equipment, shall not be
> required to comply with 690.12.
>  
> The wording is interesting.  The requirement is directed at “PV system 
> circuits…”, not PV arrays.  The passage does not specify where the PV feeding 
> those circuits is located, it just addresses where the circuits are, 
> specifically “in or on a building.”
>  
> The only circuits that are exempt are those feeding a building that serves 
> only one purpose, to house PV equipment.  For circuits that enter building 
> with other uses—homes, garages, barns, workshops, etc.-- it would seem there 
> is a requirement to have rapid shutdown systems (RSS).
>  
> Reading through the rest of the section, I don’t see any language that gets 
> us out of the requirement to reduce voltages to less than 80 volts within 30 
> seconds inside the array boundary, as in module level shutdown, regardless of 
> roof-top or ground-mount.  Although the 2020 code includes some differing 
> language, I don’t see it as exempting ground mount systems.
>  
> The moral of the story is this:  For ground-mounts:  either install RSS or 
> put your equipment (inverters, charge controllers, batteries, BOS) in a 
> separate building housing only that equipment.
>  
> I don’t necessarily like the requirement, but I think it exists.  Jay, or 
> anyone, please, please tell me I am reading this incorrectly. 
>  
> By the way, regarding battery circuits, here is a quote from a post by Bill 
> Brooks on March 16, 2016:
>  
> In the 2017 NEC, we were very careful to carve out all batteries and loads,
> that were previously part of PV systems, and place them in their own
> articles.
>  
> I have not read through the battery sections of the code to verify this, I am 
> taking Bill at his word.
>  
> William Miller
>  
> Miller Solar
> 17395 Oak Road, Atascadero, CA 93422
> 805-438-5600
> www.millersolar.com
> CA Lic. 773985
>  
>  
> From: Jay [mailto:jay.pe...@gmail.com] 
> Sent: Tuesday, February 1, 2022 6:07 AM
> To: will...@millersolar.com; RE-wrenches
> Subject: Re: [RE-wrenches] Rapid Shutdown for Off-grid systems
>  
> 2017 code has a specific exception/clarification for ground mount solar that 
> it does not need RS. 
> It’s in the first line after 690.12
>  
> Jay
>  
> 
> On Feb 1, 2022, at 12:13 AM, William Miller  wrote:
> 
> 
> Jerry:
>  
> Yes it is required.  Rapid Shutdown:  NEC 690.12.  All buildings except 
> dedicated solar buildings.  Read it and weep.
>  
> William
>  
> Miller Solar
> 17395 Oak Road, Atascadero, CA 93422
> 805-438-5600
> www.millersolar.com
> CA Lic. 773985
>  
>  
> From: Jerry Shafer [mailto:jerrysgarag...@gmail.com] 
> Sent: Monday, January 31, 2022 7:21 PM
> To: William Miller; RE-wrenches
> Subject: Re: [RE-wrenches] Rapid Shutdown for Off-grid systems
>  
> William
> Are you sure RSD is required on a non habitable buildin

Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[Brian Mehalic]

A switch, outside of the building, opening the PV circuit to the power 
electronics, and functioning as the pv system disco and the rapid shutdown 
initiation device, should be all that is required. 

Brian

> On Feb 1, 2022, at 11:43 AM, Christopher Warfel 
>  wrote:
> 
> 
> That was my understanding too, but the language Jay has from 2017 (and I 
> confirmed in 2020) reads different.  I was positive ground mounted arrays did 
> not need to comply with RSS. The bogus argument made by the businesses 
> influencing the CMP, and by a few mercenaries supposedly representing 
> firefighter concerns was explicitly for roof mounted systems going through 
> its history.  Chris
> 
>> On 2/1/2022 1:11 PM, Ray wrote:
>>  Ground mounts do NOT require RSS.  We hashed this out years ago on the 
>> Wrenches list, when NEC 2017 came out.
>> 
>> See Figure 690.1(B) Note (2): " The PV system disconnect in these diagrams 
>> separates the PV system from all other systems".
>> 
>> Thus, the PV disconnect is defined as the transition point from the PV 
>> system to all other systems, like battery or inverter systems. The 
>> installer/ designer decides where to put that disconnect.  I usually put it 
>> on the wall before it goes into the building, and I have never had an 
>> inspector question that. 
>> 
>> Thanks,
>> 
>> Ray Walters
>> Remote Solar
>> 303 505-8760
>> On 2/1/22 10:06 AM, William Miller wrote:
>>> Jay:
>>>  
>>> Here is the text from 2017:
>>>  
>>> 690.12 Rapid Shutdown of PV Systems on Buildings. PV
>>> system circuits installed on or in buildings shall include a rapid
>>> shutdown function to reduce shock hazard for emergency
>>> responders in accordance with 690.12(A) through (D).
>>>  
>>> Exception: Ground mounted PV system circuits that enter buildings, of
>>> which the sole purpose is to house PV system equipment, shall not be
>>> required to comply with 690.12.
>>>  
>>> The wording is interesting.  The requirement is directed at “PV system 
>>> circuits…”, not PV arrays.  The passage does not specify where the PV 
>>> feeding those circuits is located, it just addresses where the circuits 
>>> are, specifically “in or on a building.”
>>>  
>>> The only circuits that are exempt are those feeding a building that serves 
>>> only one purpose, to house PV equipment.  For circuits that enter building 
>>> with other uses—homes, garages, barns, workshops, etc.-- it would seem 
>>> there is a requirement to have rapid shutdown systems (RSS).
>>>  
>>> Reading through the rest of the section, I don’t see any language that gets 
>>> us out of the requirement to reduce voltages to less than 80 volts within 
>>> 30 seconds inside the array boundary, as in module level shutdown, 
>>> regardless of roof-top or ground-mount.  Although the 2020 code includes 
>>> some differing language, I don’t see it as exempting ground mount systems.
>>>  
>>> The moral of the story is this:  For ground-mounts:  either install RSS or 
>>> put your equipment (inverters, charge controllers, batteries, BOS) in a 
>>> separate building housing only that equipment.
>>>  
>>> I don’t necessarily like the requirement, but I think it exists.  Jay, or 
>>> anyone, please, please tell me I am reading this incorrectly. 
>>>  
>>> By the way, regarding battery circuits, here is a quote from a post by Bill 
>>> Brooks on March 16, 2016:
>>>  
>>> In the 2017 NEC, we were very careful to carve out all batteries and loads,
>>> that were previously part of PV systems, and place them in their own
>>> articles.
>>>  
>>> I have not read through the battery sections of the code to verify this, I 
>>> am taking Bill at his word.
>>>  
>>> William Miller
>>>  
>>> Miller Solar
>>> 17395 Oak Road, Atascadero, CA 93422
>>> 805-438-5600
>>> www.millersolar.com
>>> CA Lic. 773985
>>>  
>>>  
>>> From: Jay [mailto:jay.pe...@gmail.com] 
>>> Sent: Tuesday, February 1, 2022 6:07 AM
>>> To: will...@millersolar.com; RE-wrenches
>>> Subject: Re: [RE-wrenches] Rapid Shutdown for Off-grid systems
>>>  
>>> 2017 code has a specific exception/clarification for ground mount solar 
>>> that it does not need RS. 
>>> It’s in the first line after 690.12
>>>  
>>> Jay
>>> 
>>> 
>>> On Feb 1, 2022, at 12:13 AM

Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[William Miller]

Ray:



Thanks for that input.  I was hoping I was wrong.  I looked for that
discussion in the archives but could not find it.



William



Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com

CA Lic. 773985





*From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On
Behalf Of *Ray
*Sent:* Tuesday, February 1, 2022 10:11 AM
*To:* re-wrenches@lists.re-wrenches.org
*Subject:* Re: [RE-wrenches] Rapid Shutdown for Off-grid systems



 Ground mounts do NOT require RSS.  We hashed this out years ago on the
Wrenches list, when NEC 2017 came out.

See Figure 690.1(B) Note (2): *" The PV system disconnect in these diagrams
separates the PV system from all other systems".*

Thus, the PV disconnect is defined as the transition point from the PV
system to all other systems, like battery or inverter systems. The
installer/ designer decides where to put that disconnect.  I usually put it
on the wall before it goes into the building, and I have never had an
inspector question that.

Thanks,

Ray Walters

Remote Solar

303 505-8760

On 2/1/22 10:06 AM, William Miller wrote:

Jay:



Here is the text from 2017:



*690.12 Rapid Shutdown of PV Systems on Buildings. PV*

*system circuits installed on or in buildings shall include a rapid*

*shutdown function to reduce shock hazard for emergency*

*responders in accordance with 690.12(A) through (D).*



*Exception: Ground mounted PV system circuits that enter buildings, of*

*which the sole purpose is to house PV system equipment, shall not be*

*required to comply with 690.12.*



The wording is interesting.  The requirement is directed at “PV system
circuits…”, not PV arrays.  The passage does not specify where the PV
feeding those circuits is located, it just addresses where the circuits
are, specifically “in or on a building.”



The only circuits that are exempt are those feeding a building that serves
only one purpose, to house PV equipment.  For circuits that enter building
with other uses—homes, garages, barns, workshops, etc.-- it would seem
there is a requirement to have rapid shutdown systems (RSS).



Reading through the rest of the section, I don’t see any language that gets
us out of the requirement to reduce voltages to less than 80 volts within
30 seconds inside the array boundary, as in module level shutdown,
regardless of roof-top or ground-mount.  Although the 2020 code includes
some differing language, I don’t see it as exempting ground mount systems.



The moral of the story is this:  For ground-mounts:  either install RSS or
put your equipment (inverters, charge controllers, batteries, BOS) in a
separate building housing only that equipment.



I don’t necessarily like the requirement, but I think it exists.  Jay, or
anyone, please, please tell me I am reading this incorrectly.



By the way, regarding battery circuits, here is a quote from a post by Bill
Brooks on March 16, 2016:



*In the 2017 NEC, we were very careful to carve out all batteries and
loads,*

*that were previously part of PV systems, and place them in their own*

*articles.*



I have not read through the battery sections of the code to verify this, I
am taking Bill at his word.



William Miller



Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com

CA Lic. 773985





*From:* Jay [mailto:jay.pe...@gmail.com]
*Sent:* Tuesday, February 1, 2022 6:07 AM
*To:* will...@millersolar.com; RE-wrenches
*Subject:* Re: [RE-wrenches] Rapid Shutdown for Off-grid systems



2017 code has a specific exception/clarification for ground mount solar
that it does not need RS.

It’s in the first line after 690.12



Jay



On Feb 1, 2022, at 12:13 AM, William Miller  wrote:



Jerry:



Yes it is required.  Rapid Shutdown:  NEC 690.12.  All buildings except
dedicated solar buildings.  Read it and weep.



William



Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com

CA Lic. 773985





*From:* Jerry Shafer [mailto:jerrysgarag...@gmail.com]
*Sent:* Monday, January 31, 2022 7:21 PM
*To:* William Miller; RE-wrenches
*Subject:* Re: [RE-wrenches] Rapid Shutdown for Off-grid systems



William

Are you sure RSD is required on a non habitable building, historically its
not required. Now that being said we use fire raptor with the best results,
yes it takes an extra conduite and might require a button and power supply
depending on inverter application.

Jerry



On Mon, Jan 31, 2022, 9:57 AM William Miller 
wrote:

Friends:



It is quite rare for us to install off-grid systems on roof-tops.  We have
one coming up with about 20kW on a large barn roof.  This will be our first
off-grid with a module-level rapid shutdown requirement.  I see no
exemptions from RSS for off-grid systems in the code.  I have looked at the
options and this is what I have found:



1.   Fire Raptor

2.   Tigo TS4-F

3.   AC coupling with micro-inverters or optimizers



No one of these approaches s

Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[Christopher Warfel]

That was my understanding too, but the language Jay has from 2017 (and I 
confirmed in 2020) reads different.  I was positive ground mounted 
arrays did not need to comply with RSS. The bogus argument made by the 
businesses influencing the CMP, and by a few mercenaries supposedly 
representing firefighter concerns was explicitly for roof mounted 
systems going through its history.  Chris


On 2/1/2022 1:11 PM, Ray wrote:


 Ground mounts do NOT require RSS.  We hashed this out years ago on 
the Wrenches list, when NEC 2017 came out.


See Figure 690.1(B) Note (2): /" The PV system disconnect in these 
diagrams separates the PV system from all other systems"./


Thus, the PV disconnect is defined as the transition point from the PV 
system to all other systems, like battery or inverter systems. The 
installer/ designer decides where to put that disconnect.  I usually 
put it on the wall before it goes into the building, and I have never 
had an inspector question that.


Thanks,

Ray Walters
Remote Solar
303 505-8760
On 2/1/22 10:06 AM, William Miller wrote:


Jay:

Here is the text from 2017:

/690.12 Rapid Shutdown of PV Systems on Buildings. PV/

/system circuits installed on or in buildings shall include a rapid/

/shutdown function to reduce shock hazard for emergency/

/responders in accordance with 690.12(A) through (D)./

//

/Exception: Ground mounted PV system circuits that enter buildings, of/

/which the sole purpose is to house PV system equipment, shall not be/

/required to comply with 690.12./

The wording is interesting.  The requirement is directed at “PV 
system circuits…”, not PV arrays.  The passage does not specify where 
the PV feeding those circuits is located, it just addresses where the 
circuits are, specifically “in or on a building.”


The only circuits that are exempt are those feeding a building that 
serves only one purpose, to house PV equipment.  For circuits that 
enter building with other uses—homes, garages, barns, workshops, 
etc.-- it would seem there is a requirement to have rapid shutdown 
systems (RSS).


Reading through the rest of the section, I don’t see any language 
that gets us out of the requirement to reduce voltages to less than 
80 volts within 30 seconds inside the array boundary, as in module 
level shutdown, regardless of roof-top or ground-mount.  Although the 
2020 code includes some differing language, I don’t see it as 
exempting ground mount systems.


The moral of the story is this:  For ground-mounts:  either install 
RSS or put your equipment (inverters, charge controllers, batteries, 
BOS) in a separate building housing only that equipment.


I don’t necessarily like the requirement, but I think it exists.  
Jay, or anyone, please, please tell me I am reading this incorrectly.


By the way, regarding battery circuits, here is a quote from a post 
by Bill Brooks on March 16, 2016:


/In the 2017 NEC, we were very careful to carve out all batteries and 
loads,/


/that were previously part of PV systems, and place them in their own/

/articles./

I have not read through the battery sections of the code to verify 
this, I am taking Bill at his word.


William Miller

Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com <http://www.millersolar.com/>

CA Lic. 773985

*From:*Jay [mailto:jay.pe...@gmail.com]
*Sent:* Tuesday, February 1, 2022 6:07 AM
*To:* will...@millersolar.com; RE-wrenches
*Subject:* Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

2017 code has a specific exception/clarification for ground mount 
solar that it does not need RS.


It’s in the first line after 690.12

Jay



On Feb 1, 2022, at 12:13 AM, William Miller  
wrote:




Jerry:

Yes it is required.  Rapid Shutdown:  NEC 690.12.  All buildings
except dedicated solar buildings.  Read it and weep.

William

Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com <http://www.millersolar.com/>

CA Lic. 773985

*From:*Jerry Shafer [mailto:jerrysgarag...@gmail.com]
*Sent:* Monday, January 31, 2022 7:21 PM
*To:* William Miller; RE-wrenches
    *Subject:* Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

William

Are you sure RSD is required on a non habitable building,
historically its not required. Now that being said we use fire
raptor with the best results, yes it takes an extra conduite and
might require a button and power supply depending on inverter
application.

Jerry

On Mon, Jan 31, 2022, 9:57 AM William Miller
 wrote:

Friends:

It is quite rare for us to install off-grid systems on
roof-tops.  We have one coming up with about 20kW on a large
barn roof.  This will be our first off-grid with a
module-level rapid shutdown requirement.  I see no exemptions
from RSS for off-grid systems in the code.  I have looked at
the options and thi

Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[Christopher Warfel]

Hi, If I put a disconnect switch within one foot of the ground mounted 
array, I am pretty sure this would comply with RSS requirements?  Chris


On 2/1/2022 12:06 PM, William Miller wrote:


Jay:

Here is the text from 2017:

/690.12 Rapid Shutdown of PV Systems on Buildings. PV/

/system circuits installed on or in buildings shall include a rapid/

/shutdown function to reduce shock hazard for emergency/

/responders in accordance with 690.12(A) through (D)./

//

/Exception: Ground mounted PV system circuits that enter buildings, of/

/which the sole purpose is to house PV system equipment, shall not be/

/required to comply with 690.12./

The wording is interesting.  The requirement is directed at “PV system 
circuits…”, not PV arrays.  The passage does not specify where the PV 
feeding those circuits is located, it just addresses where the 
circuits are, specifically “in or on a building.”


The only circuits that are exempt are those feeding a building that 
serves only one purpose, to house PV equipment.  For circuits that 
enter building with other uses—homes, garages, barns, workshops, 
etc.-- it would seem there is a requirement to have rapid shutdown 
systems (RSS).


Reading through the rest of the section, I don’t see any language that 
gets us out of the requirement to reduce voltages to less than 80 
volts within 30 seconds inside the array boundary, as in module level 
shutdown, regardless of roof-top or ground-mount.  Although the 2020 
code includes some differing language, I don’t see it as exempting 
ground mount systems.


The moral of the story is this:  For ground-mounts:  either install 
RSS or put your equipment (inverters, charge controllers, batteries, 
BOS) in a separate building housing only that equipment.


I don’t necessarily like the requirement, but I think it exists.  Jay, 
or anyone, please, please tell me I am reading this incorrectly.


By the way, regarding battery circuits, here is a quote from a post by 
Bill Brooks on March 16, 2016:


/In the 2017 NEC, we were very careful to carve out all batteries and 
loads,/


/that were previously part of PV systems, and place them in their own/

/articles./

I have not read through the battery sections of the code to verify 
this, I am taking Bill at his word.


William Miller

Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com <http://www.millersolar.com/>

CA Lic. 773985

*From:*Jay [mailto:jay.pe...@gmail.com]
*Sent:* Tuesday, February 1, 2022 6:07 AM
*To:* will...@millersolar.com; RE-wrenches
*Subject:* Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

2017 code has a specific exception/clarification for ground mount 
solar that it does not need RS.


It’s in the first line after 690.12

Jay



On Feb 1, 2022, at 12:13 AM, William Miller  
wrote:




Jerry:

Yes it is required.  Rapid Shutdown:  NEC 690.12.  All buildings
except dedicated solar buildings.  Read it and weep.

William

Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com <http://www.millersolar.com/>

CA Lic. 773985

*From:*Jerry Shafer [mailto:jerrysgarag...@gmail.com]
*Sent:* Monday, January 31, 2022 7:21 PM
*To:* William Miller; RE-wrenches
    *Subject:* Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

William

Are you sure RSD is required on a non habitable building,
historically its not required. Now that being said we use fire
raptor with the best results, yes it takes an extra conduite and
might require a button and power supply depending on inverter
application.

Jerry

On Mon, Jan 31, 2022, 9:57 AM William Miller
 wrote:

Friends:

It is quite rare for us to install off-grid systems on
roof-tops.  We have one coming up with about 20kW on a large
barn roof.  This will be our first off-grid with a
module-level rapid shutdown requirement.  I see no exemptions
from RSS for off-grid systems in the code.  I have looked at
the options and this is what I have found:

1.Fire Raptor

2.Tigo TS4-F

3.AC coupling with micro-inverters or optimizers

No one of these approaches seems ideal.  The fire raptor
requires extra wiring for control leads.  The Tigo requires a
wireless control system which worries me about reliability. 
With AC Coupling systems floating the proposed AGM batteries
may be awkward.  Furthermore, with AC coupled systems one
cannot charge batteries unless the mini-grid is operational, a
big problem.

Have any of you implemented module-level RSS on a
battery-based inverter system?  I looked in the archives and
found no threads that apply.  Thank in advance.

William Miller

Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersol

Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[Ray]

 Ground mounts do NOT require RSS.  We hashed this out years ago on the 
Wrenches list, when NEC 2017 came out.


See Figure 690.1(B) Note (2): /" The PV system disconnect in these 
diagrams separates the PV system from all other systems"./


Thus, the PV disconnect is defined as the transition point from the PV 
system to all other systems, like battery or inverter systems. The 
installer/ designer decides where to put that disconnect.  I usually put 
it on the wall before it goes into the building, and I have never had an 
inspector question that.


Thanks,

Ray Walters
Remote Solar
303 505-8760

On 2/1/22 10:06 AM, William Miller wrote:


Jay:

Here is the text from 2017:

/690.12 Rapid Shutdown of PV Systems on Buildings. PV/

/system circuits installed on or in buildings shall include a rapid/

/shutdown function to reduce shock hazard for emergency/

/responders in accordance with 690.12(A) through (D)./

//

/Exception: Ground mounted PV system circuits that enter buildings, of/

/which the sole purpose is to house PV system equipment, shall not be/

/required to comply with 690.12./

The wording is interesting.  The requirement is directed at “PV system 
circuits…”, not PV arrays.  The passage does not specify where the PV 
feeding those circuits is located, it just addresses where the 
circuits are, specifically “in or on a building.”


The only circuits that are exempt are those feeding a building that 
serves only one purpose, to house PV equipment.  For circuits that 
enter building with other uses—homes, garages, barns, workshops, 
etc.-- it would seem there is a requirement to have rapid shutdown 
systems (RSS).


Reading through the rest of the section, I don’t see any language that 
gets us out of the requirement to reduce voltages to less than 80 
volts within 30 seconds inside the array boundary, as in module level 
shutdown, regardless of roof-top or ground-mount.  Although the 2020 
code includes some differing language, I don’t see it as exempting 
ground mount systems.


The moral of the story is this:  For ground-mounts:  either install 
RSS or put your equipment (inverters, charge controllers, batteries, 
BOS) in a separate building housing only that equipment.


I don’t necessarily like the requirement, but I think it exists.  Jay, 
or anyone, please, please tell me I am reading this incorrectly.


By the way, regarding battery circuits, here is a quote from a post by 
Bill Brooks on March 16, 2016:


/In the 2017 NEC, we were very careful to carve out all batteries and 
loads,/


/that were previously part of PV systems, and place them in their own/

/articles./

I have not read through the battery sections of the code to verify 
this, I am taking Bill at his word.


William Miller

Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com <http://www.millersolar.com/>

CA Lic. 773985

*From:*Jay [mailto:jay.pe...@gmail.com]
*Sent:* Tuesday, February 1, 2022 6:07 AM
*To:* will...@millersolar.com; RE-wrenches
*Subject:* Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

2017 code has a specific exception/clarification for ground mount 
solar that it does not need RS.


It’s in the first line after 690.12

Jay



On Feb 1, 2022, at 12:13 AM, William Miller  
wrote:




Jerry:

Yes it is required.  Rapid Shutdown:  NEC 690.12.  All buildings
except dedicated solar buildings.  Read it and weep.

William

Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com <http://www.millersolar.com/>

CA Lic. 773985

*From:*Jerry Shafer [mailto:jerrysgarag...@gmail.com]
*Sent:* Monday, January 31, 2022 7:21 PM
*To:* William Miller; RE-wrenches
    *Subject:* Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

William

Are you sure RSD is required on a non habitable building,
historically its not required. Now that being said we use fire
raptor with the best results, yes it takes an extra conduite and
might require a button and power supply depending on inverter
application.

Jerry

On Mon, Jan 31, 2022, 9:57 AM William Miller
 wrote:

Friends:

It is quite rare for us to install off-grid systems on
roof-tops.  We have one coming up with about 20kW on a large
barn roof.  This will be our first off-grid with a
module-level rapid shutdown requirement.  I see no exemptions
from RSS for off-grid systems in the code.  I have looked at
the options and this is what I have found:

1.Fire Raptor

2.Tigo TS4-F

3.AC coupling with micro-inverters or optimizers

No one of these approaches seems ideal.  The fire raptor
requires extra wiring for control leads.  The Tigo requires a
wireless control system which worries me about reliability. 
With AC Coupling systems floating the proposed AGM batteries
may be awkward.

Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[William Miller]

Jay:



Here is the text from 2017:



*690.12 Rapid Shutdown of PV Systems on Buildings. PV*

*system circuits installed on or in buildings shall include a rapid*

*shutdown function to reduce shock hazard for emergency*

*responders in accordance with 690.12(A) through (D).*



*Exception: Ground mounted PV system circuits that enter buildings, of*

*which the sole purpose is to house PV system equipment, shall not be*

*required to comply with 690.12.*



The wording is interesting.  The requirement is directed at “PV system
circuits…”, not PV arrays.  The passage does not specify where the PV
feeding those circuits is located, it just addresses where the circuits
are, specifically “in or on a building.”



The only circuits that are exempt are those feeding a building that serves
only one purpose, to house PV equipment.  For circuits that enter building
with other uses—homes, garages, barns, workshops, etc.-- it would seem
there is a requirement to have rapid shutdown systems (RSS).



Reading through the rest of the section, I don’t see any language that gets
us out of the requirement to reduce voltages to less than 80 volts within
30 seconds inside the array boundary, as in module level shutdown,
regardless of roof-top or ground-mount.  Although the 2020 code includes
some differing language, I don’t see it as exempting ground mount systems.



The moral of the story is this:  For ground-mounts:  either install RSS or
put your equipment (inverters, charge controllers, batteries, BOS) in a
separate building housing only that equipment.



I don’t necessarily like the requirement, but I think it exists.  Jay, or
anyone, please, please tell me I am reading this incorrectly.



By the way, regarding battery circuits, here is a quote from a post by Bill
Brooks on March 16, 2016:



*In the 2017 NEC, we were very careful to carve out all batteries and
loads,*

*that were previously part of PV systems, and place them in their own*

*articles.*



I have not read through the battery sections of the code to verify this, I
am taking Bill at his word.



William Miller



Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com

CA Lic. 773985





*From:* Jay [mailto:jay.pe...@gmail.com]
*Sent:* Tuesday, February 1, 2022 6:07 AM
*To:* will...@millersolar.com; RE-wrenches
*Subject:* Re: [RE-wrenches] Rapid Shutdown for Off-grid systems



2017 code has a specific exception/clarification for ground mount solar
that it does not need RS.

It’s in the first line after 690.12



Jay



On Feb 1, 2022, at 12:13 AM, William Miller  wrote:



Jerry:



Yes it is required.  Rapid Shutdown:  NEC 690.12.  All buildings except
dedicated solar buildings.  Read it and weep.



William



Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com

CA Lic. 773985





*From:* Jerry Shafer [mailto:jerrysgarag...@gmail.com]
*Sent:* Monday, January 31, 2022 7:21 PM
*To:* William Miller; RE-wrenches
*Subject:* Re: [RE-wrenches] Rapid Shutdown for Off-grid systems



William

Are you sure RSD is required on a non habitable building, historically its
not required. Now that being said we use fire raptor with the best results,
yes it takes an extra conduite and might require a button and power supply
depending on inverter application.

Jerry



On Mon, Jan 31, 2022, 9:57 AM William Miller 
wrote:

Friends:



It is quite rare for us to install off-grid systems on roof-tops.  We have
one coming up with about 20kW on a large barn roof.  This will be our first
off-grid with a module-level rapid shutdown requirement.  I see no
exemptions from RSS for off-grid systems in the code.  I have looked at the
options and this is what I have found:



1.   Fire Raptor

2.   Tigo TS4-F

3.   AC coupling with micro-inverters or optimizers



No one of these approaches seems ideal.  The fire raptor requires extra
wiring for control leads.  The Tigo requires a wireless control system
which worries me about reliability.  With AC Coupling systems floating the
proposed AGM batteries may be awkward.  Furthermore, with AC coupled
systems one cannot charge batteries unless the mini-grid is operational, a
big problem.



Have any of you implemented module-level RSS on a battery-based inverter
system?  I looked in the archives and found no threads that apply.  Thank
in advance.



William Miller



Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com

CA Lic. 773985





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Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[Jay]

2017 code has a specific exception/clarification for ground mount solar that it 
does not need RS. 
It’s in the first line after 690.12

Jay

> On Feb 1, 2022, at 12:13 AM, William Miller  wrote:
> 
> 
> Jerry:
>  
> Yes it is required.  Rapid Shutdown:  NEC 690.12.  All buildings except 
> dedicated solar buildings.  Read it and weep.
>  
> William
>  
> Miller Solar
> 17395 Oak Road, Atascadero, CA 93422
> 805-438-5600
> www.millersolar.com
> CA Lic. 773985
>  
>  
> From: Jerry Shafer [mailto:jerrysgarag...@gmail.com] 
> Sent: Monday, January 31, 2022 7:21 PM
> To: William Miller; RE-wrenches
> Subject: Re: [RE-wrenches] Rapid Shutdown for Off-grid systems
>  
> William
> Are you sure RSD is required on a non habitable building, historically its 
> not required. Now that being said we use fire raptor with the best results, 
> yes it takes an extra conduite and might require a button and power supply 
> depending on inverter application.
> Jerry
>  
> On Mon, Jan 31, 2022, 9:57 AM William Miller  wrote:
> Friends:
>  
> It is quite rare for us to install off-grid systems on roof-tops.  We have 
> one coming up with about 20kW on a large barn roof.  This will be our first 
> off-grid with a module-level rapid shutdown requirement.  I see no exemptions 
> from RSS for off-grid systems in the code.  I have looked at the options and 
> this is what I have found:
>  
> 1.   Fire Raptor
> 
> 2.   Tigo TS4-F
> 
> 3.   AC coupling with micro-inverters or optimizers
> 
>  
> No one of these approaches seems ideal.  The fire raptor requires extra 
> wiring for control leads.  The Tigo requires a wireless control system which 
> worries me about reliability.  With AC Coupling systems floating the proposed 
> AGM batteries may be awkward.  Furthermore, with AC coupled systems one 
> cannot charge batteries unless the mini-grid is operational, a big problem.
>  
> Have any of you implemented module-level RSS on a battery-based inverter 
> system?  I looked in the archives and found no threads that apply.  Thank in 
> advance.
>  
> William Miller
>  
> Miller Solar
> 17395 Oak Road, Atascadero, CA 93422
> 805-438-5600
> www.millersolar.com
> CA Lic. 773985
>  
>  
> ___
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Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[William Miller]

Kirpal:



Thanks for that suggestion.  The AP Smart system modules are certainly more
compact and this is a plus for me.



Do you have to have a sensor transformer and logic unit on each string?
Could more than one string be routed through one sensor coil?  This
installation will have 10 strings so that could be a lot of hardware.



Some here have asked if RSS is required on a non-dwelling unit.  My reading
of the code indicates indeed it is.  The only buildings exempt are
buildings used solely for solar equipment that are fed by ground mount
arrays.  So theoretically our ground mount systems that feed equipment in a
barn or garage should also have RSS.  Right?  This does not make sense to
me for protecting fire-fighters.  Seems like an over-reach.  Bill Brooks,
could you comment on this?  Anyone?



William



Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com

CA Lic. 773985





*From:* Kirpal [mailto:solarwo...@gmail.com]
*Sent:* Monday, January 31, 2022 5:21 PM
*To:* RE-wrenches; William Miller
*Subject:* Re: [RE-wrenches] Rapid Shutdown for Off-grid systems



Hi William.

We have had good luck with the AP Smart Rapid shutdown system.  It is
similar to the Tigo in that it sends a "heartbeat" signal to the units up
behind each solar panel over the power wires. I haven't tried the Tigos yet
but would be open to it if the opportunity presented itself.  The thing we
like about the AP Smart shutdown units is they can be attached to the solar
panels before the panels are brought up to the roof.  Makes for a quick and
tidy installation.  We found the Fire Raptor units with their incredible
amount of extra wiring and cables to be a real pain in the ass to install.
It typically takes longer to install the Fire Raptor units and manage the
wiring than it does to install the solar panels themselves. The fire
raptors are more expensive and require a seperate control wire to be run
upto the roof.  We haven't had any failures on either the fire raptor or
the AP Smart units with probably a dozen installs of each style installed
to date.  Brad Bassett at AEE has some great easy to use wiring diagrams
for both systems with Outback or Sol Ark.  All the above systems have some
requirement for either 12V or 24V power to power the signal generator.  We
typically use some version of din rail mounted 48-24v or12V power supply
and power it from the batteries so that if the inverter were to fail or the
grid the solar can still stay on..  At this stage we have settled on any of
the rapid shutdown systems except Fire Raptor.  - if you do use the Fire
Raptor - calculate a  bunch of extra time into the install for wire
management.

Hope that gives you some food for thought.

Cheers,



Sunny Regards,
Kirpal Khalsa

Oregon LRT#25
Oregon Solarworks LLC
www.oregonsolarworks.com
541-299-0402
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Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[William Miller]

Jerry:



Yes it is required.  Rapid Shutdown:  NEC 690.12.  All buildings except
dedicated solar buildings.  Read it and weep.



William



Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com

CA Lic. 773985





*From:* Jerry Shafer [mailto:jerrysgarag...@gmail.com]
*Sent:* Monday, January 31, 2022 7:21 PM
*To:* William Miller; RE-wrenches
*Subject:* Re: [RE-wrenches] Rapid Shutdown for Off-grid systems



William

Are you sure RSD is required on a non habitable building, historically its
not required. Now that being said we use fire raptor with the best results,
yes it takes an extra conduite and might require a button and power supply
depending on inverter application.

Jerry



On Mon, Jan 31, 2022, 9:57 AM William Miller 
wrote:

Friends:



It is quite rare for us to install off-grid systems on roof-tops.  We have
one coming up with about 20kW on a large barn roof.  This will be our first
off-grid with a module-level rapid shutdown requirement.  I see no
exemptions from RSS for off-grid systems in the code.  I have looked at the
options and this is what I have found:



1.   Fire Raptor

2.   Tigo TS4-F

3.   AC coupling with micro-inverters or optimizers



No one of these approaches seems ideal.  The fire raptor requires extra
wiring for control leads.  The Tigo requires a wireless control system
which worries me about reliability.  With AC Coupling systems floating the
proposed AGM batteries may be awkward.  Furthermore, with AC coupled
systems one cannot charge batteries unless the mini-grid is operational, a
big problem.



Have any of you implemented module-level RSS on a battery-based inverter
system?  I looked in the archives and found no threads that apply.  Thank
in advance.



William Miller



Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com

CA Lic. 773985





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Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[Jerry Shafer]

William
Are you sure RSD is required on a non habitable building, historically its
not required. Now that being said we use fire raptor with the best results,
yes it takes an extra conduite and might require a button and power supply
depending on inverter application.
Jerry

On Mon, Jan 31, 2022, 9:57 AM William Miller 
wrote:

> Friends:
>
>
>
> It is quite rare for us to install off-grid systems on roof-tops.  We have
> one coming up with about 20kW on a large barn roof.  This will be our first
> off-grid with a module-level rapid shutdown requirement.  I see no
> exemptions from RSS for off-grid systems in the code.  I have looked at the
> options and this is what I have found:
>
>
>
> 1.   Fire Raptor
>
> 2.   Tigo TS4-F
>
> 3.   AC coupling with micro-inverters or optimizers
>
>
>
> No one of these approaches seems ideal.  The fire raptor requires extra
> wiring for control leads.  The Tigo requires a wireless control system
> which worries me about reliability.  With AC Coupling systems floating the
> proposed AGM batteries may be awkward.  Furthermore, with AC coupled
> systems one cannot charge batteries unless the mini-grid is operational, a
> big problem.
>
>
>
> Have any of you implemented module-level RSS on a battery-based inverter
> system?  I looked in the archives and found no threads that apply.  Thank
> in advance.
>
>
>
> William Miller
>
>
>
> Miller Solar
>
> 17395 Oak Road, Atascadero, CA 93422
>
> 805-438-5600
>
> www.millersolar.com
>
> CA Lic. 773985
>
>
>
>
> ___
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Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[Dave Tedeyan]

I also recently used the Tigo with Sol-Ark to provide the 12V signal with
good success. The Tigo transmitter can also (barely) fit inside the Sol-Ark
wiring compartment, so you do not need the whole Tigo enclosure for it.
Cheers,
Dave

On Mon, Jan 31, 2022 at 8:21 PM Kirpal  wrote:

> Hi William.
> We have had good luck with the AP Smart Rapid shutdown system.  It is
> similar to the Tigo in that it sends a "heartbeat" signal to the units up
> behind each solar panel over the power wires. I haven't tried the Tigos yet
> but would be open to it if the opportunity presented itself.  The thing we
> like about the AP Smart shutdown units is they can be attached to the solar
> panels before the panels are brought up to the roof.  Makes for a quick and
> tidy installation.  We found the Fire Raptor units with their incredible
> amount of extra wiring and cables to be a real pain in the ass to install.
> It typically takes longer to install the Fire Raptor units and manage the
> wiring than it does to install the solar panels themselves. The fire
> raptors are more expensive and require a seperate control wire to be run
> upto the roof.  We haven't had any failures on either the fire raptor or
> the AP Smart units with probably a dozen installs of each style installed
> to date.  Brad Bassett at AEE has some great easy to use wiring diagrams
> for both systems with Outback or Sol Ark.  All the above systems have some
> requirement for either 12V or 24V power to power the signal generator.  We
> typically use some version of din rail mounted 48-24v or12V power supply
> and power it from the batteries so that if the inverter were to fail or the
> grid the solar can still stay on..  At this stage we have settled on any of
> the rapid shutdown systems except Fire Raptor.  - if you do use the Fire
> Raptor - calculate a  bunch of extra time into the install for wire
> management.
> Hope that gives you some food for thought.
> Cheers,
>
> Sunny Regards,
> Kirpal Khalsa
> Oregon LRT#25
> Oregon Solarworks LLC
> www.oregonsolarworks.com
> 541-299-0402
>
>
>
>>
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-- 
[image: Logo] 
Dave Tedeyan, P.E.
Owner | Sungineer Solar
p: he | him | his
a: 1653 Slaterville Rd. | Ithaca, NY 14850
w: www.sungineersolar.com 
c: (607) 288-2898
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Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[Kirpal]

Hi William.
We have had good luck with the AP Smart Rapid shutdown system.  It is
similar to the Tigo in that it sends a "heartbeat" signal to the units up
behind each solar panel over the power wires. I haven't tried the Tigos yet
but would be open to it if the opportunity presented itself.  The thing we
like about the AP Smart shutdown units is they can be attached to the solar
panels before the panels are brought up to the roof.  Makes for a quick and
tidy installation.  We found the Fire Raptor units with their incredible
amount of extra wiring and cables to be a real pain in the ass to install.
It typically takes longer to install the Fire Raptor units and manage the
wiring than it does to install the solar panels themselves. The fire
raptors are more expensive and require a seperate control wire to be run
upto the roof.  We haven't had any failures on either the fire raptor or
the AP Smart units with probably a dozen installs of each style installed
to date.  Brad Bassett at AEE has some great easy to use wiring diagrams
for both systems with Outback or Sol Ark.  All the above systems have some
requirement for either 12V or 24V power to power the signal generator.  We
typically use some version of din rail mounted 48-24v or12V power supply
and power it from the batteries so that if the inverter were to fail or the
grid the solar can still stay on..  At this stage we have settled on any of
the rapid shutdown systems except Fire Raptor.  - if you do use the Fire
Raptor - calculate a  bunch of extra time into the install for wire
management.
Hope that gives you some food for thought.
Cheers,

Sunny Regards,
Kirpal Khalsa
Oregon LRT#25
Oregon Solarworks LLC
www.oregonsolarworks.com
541-299-0402



>
>
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Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[Vic Guillot]

William,
We did one this year, offgrid, Outback Radian with Simpliphi batteries.
Used the outback rapid shutdown option which is probably similar to the
fire raptor system.
Cheers!,
Vic Guillot

Vic Guillot
Sol Sierra, Inc.
209.795.3554 office
209.768.3560 mobile/text



On Mon, Jan 31, 2022 at 9:57 AM William Miller 
wrote:

> Friends:
>
>
>
> It is quite rare for us to install off-grid systems on roof-tops.  We have
> one coming up with about 20kW on a large barn roof.  This will be our first
> off-grid with a module-level rapid shutdown requirement.  I see no
> exemptions from RSS for off-grid systems in the code.  I have looked at the
> options and this is what I have found:
>
>
>
> 1.   Fire Raptor
>
> 2.   Tigo TS4-F
>
> 3.   AC coupling with micro-inverters or optimizers
>
>
>
> No one of these approaches seems ideal.  The fire raptor requires extra
> wiring for control leads.  The Tigo requires a wireless control system
> which worries me about reliability.  With AC Coupling systems floating the
> proposed AGM batteries may be awkward.  Furthermore, with AC coupled
> systems one cannot charge batteries unless the mini-grid is operational, a
> big problem.
>
>
>
> Have any of you implemented module-level RSS on a battery-based inverter
> system?  I looked in the archives and found no threads that apply.  Thank
> in advance.
>
>
>
> William Miller
>
>
>
> 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@lists.re-wrenches.org
>
> Change listserver email address & settings:
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Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[penobscotsolar]

Hi William,
   We have a half dozen plus off grid systems using SolArk inverters and
TIGO optimizers. They work well and the TIGO's, from my experience,
have been really reliable. The necessary 12 volt signal can come
directly from the relay in the SolArk inverter.

Best,
Daryl DeJoy
NABCEP Certified PV
Penobscot Solar Design



> Friends:
>
>
>
> It is quite rare for us to install off-grid systems on roof-tops.  We have
> one coming up with about 20kW on a large barn roof.  This will be our
> first
> off-grid with a module-level rapid shutdown requirement.  I see no
> exemptions from RSS for off-grid systems in the code.  I have looked at
> the
> options and this is what I have found:
>
>
>
> 1.   Fire Raptor
>
> 2.   Tigo TS4-F
>
> 3.   AC coupling with micro-inverters or optimizers
>
>
>
> No one of these approaches seems ideal.  The fire raptor requires extra
> wiring for control leads.  The Tigo requires a wireless control system
> which worries me about reliability.  With AC Coupling systems floating the
> proposed AGM batteries may be awkward.  Furthermore, with AC coupled
> systems one cannot charge batteries unless the mini-grid is operational, a
> big problem.
>
>
>
> Have any of you implemented module-level RSS on a battery-based inverter
> system?  I looked in the archives and found no threads that apply.  Thank
> in advance.
>
>
>
> William Miller
>
>
>
> 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
>
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Re: [RE-wrenches] Rapid Shutdown for Off-grid systems

[Chris Sparadeo]

Hi William,

I have had good luck with the Tigo TS4-AF. Although it does require a 12VDC
power supply for it's RSD transmitter, Outback, Sol Ark and Schnieder have
a straight forward integration not requiring dependency of AC output from
inverter.

Best,

Chris

On Mon, Jan 31, 2022 at 12:57 PM William Miller 
wrote:

> Friends:
>
>
>
> It is quite rare for us to install off-grid systems on roof-tops.  We have
> one coming up with about 20kW on a large barn roof.  This will be our first
> off-grid with a module-level rapid shutdown requirement.  I see no
> exemptions from RSS for off-grid systems in the code.  I have looked at the
> options and this is what I have found:
>
>
>
> 1.   Fire Raptor
>
> 2.   Tigo TS4-F
>
> 3.   AC coupling with micro-inverters or optimizers
>
>
>
> No one of these approaches seems ideal.  The fire raptor requires extra
> wiring for control leads.  The Tigo requires a wireless control system
> which worries me about reliability.  With AC Coupling systems floating the
> proposed AGM batteries may be awkward.  Furthermore, with AC coupled
> systems one cannot charge batteries unless the mini-grid is operational, a
> big problem.
>
>
>
> Have any of you implemented module-level RSS on a battery-based inverter
> system?  I looked in the archives and found no threads that apply.  Thank
> in advance.
>
>
>
> William Miller
>
>
>
> 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@lists.re-wrenches.org
>
> Change listserver email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
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> There are two list archives for searching. When one doesn't work, try the
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[RE-wrenches] Rapid Shutdown for Off-grid systems

[William Miller]

Friends:



It is quite rare for us to install off-grid systems on roof-tops.  We have
one coming up with about 20kW on a large barn roof.  This will be our first
off-grid with a module-level rapid shutdown requirement.  I see no
exemptions from RSS for off-grid systems in the code.  I have looked at the
options and this is what I have found:



1.   Fire Raptor

2.   Tigo TS4-F

3.   AC coupling with micro-inverters or optimizers



No one of these approaches seems ideal.  The fire raptor requires extra
wiring for control leads.  The Tigo requires a wireless control system
which worries me about reliability.  With AC Coupling systems floating the
proposed AGM batteries may be awkward.  Furthermore, with AC coupled
systems one cannot charge batteries unless the mini-grid is operational, a
big problem.



Have any of you implemented module-level RSS on a battery-based inverter
system?  I looked in the archives and found no threads that apply.  Thank
in advance.



William Miller



Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com

CA Lic. 773985
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