Re: [RE-wrenches] Rooftop DC disconnects

[Jason Szumlanski]

"​In this scenario, there is no safe way to replace either of the two
Morningstar controllers."

The BEST rooftop disconnect remains... a big thick tarp. Not totally
practical in an emergency situation, but it is pretty fail safe.

Unfortunately for emergency responders, that does not take care of the AC
circuits in a microinverter or AC module system, but ideally the building
main is shut down anyway, and the risk is the same as any other 240V
equipment/appliance circuits.

​Jason Szumlanski



On Wed, Sep 23, 2015 at 4:26 PM, William Miller 
wrote:

> Dear Fellow Wrenches
>
>
>
> Below is a design conundrum that may resonate with some of you:
>
>
>
> We are finalizing a design for an off-grid residential system.  The
> customer insist the PV should be on the roof and pre-installed a 1-1/4” PVC
> conduit from his roof to a crawl space, in anticipation of a solar
> install.  This created real problems, because we all know we can’t pull PV
> source or output circuits in (or now, on)  the envelopes of habitable
> buildings.
>
>
>
> There was no practical way to replace the PVC.  We contrived a method to
> sleeve ¾” liquid-tight through the 1-1/4” PVC to the crawl space,
> continuing on with EMT.  This is the largest metallic conduit we could
> fit.  The distance was greater than 10 feet so we couldn’t use EMT.  Due to
> the conduit size restriction, we upgraded to Morningstar 600 volt charge
> controllers, allowing us to reduce conductor size.
>
>
>
> (As a sidebar, although the Morningstar is listed as a 600 volt charge
> controller, we have found no circumstance were we could take advantage of
> that high a voltage.  With the currently available high wattage modules, by
> the time we added enough in series to get to 600 volts, we were well beyond
> the wattage capabilities of the controller.  For sake of design
> considerations, I suggest one regard these units as ~300 volt charge
> controllers.)
>
>
>
> We now have plans for 300 volt PV feeders running down an interior wall
> and under the house, with no roof-top disconnecting means.  It is my
> understanding none are required.  I am not comfortable with this.
> ​​
> In this scenario, there is no safe way to replace either of the two
> Morningstar controllers. Should someone drill through or damage the EMT in
> the wall or under the floor, there would be no way to turn off the feeder.
>
>
>
> I don’t like putting HU361RBs on a roof.  They must remain vertical and so
> they stick up too high and are hard to provide mounting for.  Sola-deck
> units are another option, but they require integrating with shingles, not
> practical on this job or many others.  I finally settled on a DC-Sunvolt
> PV-X16A-4X-RG disconnect as a possible solution.  At $216 it is not out of
> range.  The unit will provide means to turn off the feeders for service.  I
> will report back on my impressions of the unit.
>
>
>
> To distill this scenario, I don’t believe the code requires a disconnect,
> but I feel morally obligated to install one.  I’d be interested in
> verification of the code interpretation and others response to similar
> situations.
>
>
>
> I found no other options for rooftop disconnecting means that would be
> small, reasonably priced and not present a high profile.  If there are
> products I don’t know about, I would be most grateful to receive your input.
>
>
>
> While researching the hardware I stumbled upon this article, linked
> below.  It seems to present a real dilemma, but I am not convinced.  Please
> remain skeptical as you read.  It appears all of the links direct you to
> the same source.
>
>
>
>
> https://www.linkedin.com/pulse/greatest-debacle-solar-pv-australias-rooftop-dc-isolator-lucas-sadler
>
>
>
> Thanks again to all of you for helpful advice and expertise.  I learned
> about Sunvolt here, just one of many great suggestions.
>
>
>
> Sincerely,
>
>
>
> William Miller
>
>
>
>
>
> [image: Gradient Cap_mini]
> Lic 773985
> millersolar.com 
> 805-438-5600
>
>
>
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Re: [RE-wrenches] Rooftop DC disconnects

[Brian Mehalic]

I disagree about tarps. We've tested fully covered arrays (and small ones at 
that) and still had what would be considered lethal levels of current and 
voltage, even when using heavy, reflective tarps. And it can be very difficult 
to ensure they stay in place, plus it's impractical for larger arrays. 

Brian

> On Sep 24, 2015, at 6:31 AM, Jason Szumlanski 
>  wrote:
> 
> "​In this scenario, there is no safe way to replace either of the two 
> Morningstar controllers."
> 
> The BEST rooftop disconnect remains... a big thick tarp. Not totally 
> practical in an emergency situation, but it is pretty fail safe. 
> 
> Unfortunately for emergency responders, that does not take care of the AC 
> circuits in a microinverter or AC module system, but ideally the building 
> main is shut down anyway, and the risk is the same as any other 240V 
> equipment/appliance circuits.
> 
> ​Jason Szumlanski
> 
> 
> 
>> On Wed, Sep 23, 2015 at 4:26 PM, William Miller  
>> wrote:
>> Dear Fellow Wrenches
>> 
>>  
>> 
>> Below is a design conundrum that may resonate with some of you:
>> 
>>  
>> 
>> We are finalizing a design for an off-grid residential system.  The customer 
>> insist the PV should be on the roof and pre-installed a 1-1/4” PVC conduit 
>> from his roof to a crawl space, in anticipation of a solar install.  This 
>> created real problems, because we all know we can’t pull PV source or output 
>> circuits in (or now, on)  the envelopes of habitable buildings.
>> 
>>  
>> 
>> There was no practical way to replace the PVC.  We contrived a method to 
>> sleeve ¾” liquid-tight through the 1-1/4” PVC to the crawl space, continuing 
>> on with EMT.  This is the largest metallic conduit we could fit.  The 
>> distance was greater than 10 feet so we couldn’t use EMT.  Due to the 
>> conduit size restriction, we upgraded to Morningstar 600 volt charge 
>> controllers, allowing us to reduce conductor size.
>> 
>>  
>> 
>> (As a sidebar, although the Morningstar is listed as a 600 volt charge 
>> controller, we have found no circumstance were we could take advantage of 
>> that high a voltage.  With the currently available high wattage modules, by 
>> the time we added enough in series to get to 600 volts, we were well beyond 
>> the wattage capabilities of the controller.  For sake of design 
>> considerations, I suggest one regard these units as ~300 volt charge 
>> controllers.)
>> 
>>  
>> 
>> We now have plans for 300 volt PV feeders running down an interior wall and 
>> under the house, with no roof-top disconnecting means.  It is my 
>> understanding none are required.  I am not comfortable with this. 
>> 
>> ​​In this scenario, there is no safe way to replace either of the two 
>> Morningstar controllers. Should someone drill through or damage the EMT in 
>> the wall or under the floor, there would be no way to turn off the feeder.
>>  
>> 
>> I don’t like putting HU361RBs on a roof.  They must remain vertical and so 
>> they stick up too high and are hard to provide mounting for.  Sola-deck 
>> units are another option, but they require integrating with shingles, not 
>> practical on this job or many others.  I finally settled on a DC-Sunvolt 
>> PV-X16A-4X-RG disconnect as a possible solution.  At $216 it is not out of 
>> range.  The unit will provide means to turn off the feeders for service.  I 
>> will report back on my impressions of the unit.
>> 
>>  
>> 
>> To distill this scenario, I don’t believe the code requires a disconnect, 
>> but I feel morally obligated to install one.  I’d be interested in 
>> verification of the code interpretation and others response to similar 
>> situations.
>> 
>>  
>> 
>> I found no other options for rooftop disconnecting means that would be 
>> small, reasonably priced and not present a high profile.  If there are 
>> products I don’t know about, I would be most grateful to receive your input.
>> 
>>  
>> 
>> While researching the hardware I stumbled upon this article, linked below.  
>> It seems to present a real dilemma, but I am not convinced.  Please remain 
>> skeptical as you read.  It appears all of the links direct you to the same 
>> source.
>> 
>>  
>> 
>> https://www.linkedin.com/pulse/greatest-debacle-solar-pv-australias-rooftop-dc-isolator-lucas-sadler
>> 
>>  
>> 
>> Thanks again to all of you for helpful advice and expertise.  I learned 
>> about Sunvolt here, just one of many great suggestions.
>> 
>>  
>> 
>> Sincerely,
>> 
>>  
>> 
>> William Miller
>> 
>>  
>> 
>>  
>> 
>> 
>> Lic 773985
>> millersolar.com
>> 805-438-5600
>> 
> ___
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Re: [RE-wrenches] Rooftop DC disconnects

[Starlight Solar Power Systems]

William and Wrenches, 

I have pondered situations like this one and wonder the following: If a high 
voltage DC solenoid were placed at the PV array and the coil was controlled by 
an arc fault detector along with a means of manually disconnecting, would that 
not work to satisfy shut down requirements and safety concerns? 

We have been using 350A, 800 volt solenoids from Gigavac in our lithium battery 
system on both the positive and negative terminals (controlled by a CPU) to 
provide 100% disconnect if case of any battery fault. 

Larry



On Sep 23, 2015, at 2:26 PM, William Miller  wrote:

Dear Fellow Wrenches
 
Below is a design conundrum that may resonate with some of you:
 
We are finalizing a design for an off-grid residential system.  The customer 
insist the PV should be on the roof and pre-installed a 1-1/4” PVC conduit from 
his roof to a crawl space, in anticipation of a solar install.  This created 
real problems, because we all know we can’t pull PV source or output circuits 
in (or now, on)  the envelopes of habitable buildings.
 
There was no practical way to replace the PVC.  We contrived a method to sleeve 
¾” liquid-tight through the 1-1/4” PVC to the crawl space, continuing on with 
EMT.  This is the largest metallic conduit we could fit.  The distance was 
greater than 10 feet so we couldn’t use EMT.  Due to the conduit size 
restriction, we upgraded to Morningstar 600 volt charge controllers, allowing 
us to reduce conductor size.
 
(As a sidebar, although the Morningstar is listed as a 600 volt charge 
controller, we have found no circumstance were we could take advantage of that 
high a voltage.  With the currently available high wattage modules, by the time 
we added enough in series to get to 600 volts, we were well beyond the wattage 
capabilities of the controller.  For sake of design considerations, I suggest 
one regard these units as ~300 volt charge controllers.)
 
We now have plans for 300 volt PV feeders running down an interior wall and 
under the house, with no roof-top disconnecting means.  It is my understanding 
none are required.  I am not comfortable with this.  In this scenario, there is 
no safe way to replace either of the two Morningstar controllers. Should 
someone drill through or damage the EMT in the wall or under the floor, there 
would be no way to turn off the feeder.
 
I don’t like putting HU361RBs on a roof.  They must remain vertical and so they 
stick up too high and are hard to provide mounting for.  Sola-deck units are 
another option, but they require integrating with shingles, not practical on 
this job or many others.  I finally settled on a DC-Sunvolt PV-X16A-4X-RG 
disconnect as a possible solution.  At $216 it is not out of range.  The unit 
will provide means to turn off the feeders for service.  I will report back on 
my impressions of the unit.
 
To distill this scenario, I don’t believe the code requires a disconnect, but I 
feel morally obligated to install one.  I’d be interested in verification of 
the code interpretation and others response to similar situations.
 
I found no other options for rooftop disconnecting means that would be small, 
reasonably priced and not present a high profile.  If there are products I 
don’t know about, I would be most grateful to receive your input.
 
While researching the hardware I stumbled upon this article, linked below.  It 
seems to present a real dilemma, but I am not convinced.  Please remain 
skeptical as you read.  It appears all of the links direct you to the same 
source.
 
https://www.linkedin.com/pulse/greatest-debacle-solar-pv-australias-rooftop-dc-isolator-lucas-sadler
 

 
Thanks again to all of you for helpful advice and expertise.  I learned about 
Sunvolt here, just one of many great suggestions.
 
Sincerely,
 
William Miller
 
 

Lic 773985
millersolar.com 
805-438-5600



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Re: [RE-wrenches] Rooftop DC disconnects

[Ray Walters]

The other option is Midnite Solar's remote controlled breakers or 
combiner boxes.  They make up to a 250 amp breaker, but I found on large 
battery systems that we need some thing larger. Colorado is now 
requiring Rapid Disconnect for the batteries as well, which is NOT the 
original intent of that article.  Is the Gigavac UL listed?


R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760

On 9/24/2015 10:45 AM, Starlight Solar Power Systems wrote:

William and Wrenches,

I have pondered situations like this one and wonder the following: If 
a high voltage DC solenoid were placed at the PV array and the coil 
was controlled by an arc fault detector along with a means of manually 
disconnecting, would that not work to satisfy shut down requirements 
and safety concerns?


We have been using 350A, 800 volt solenoids from Gigavac in our 
lithium battery system on both the positive and negative terminals 
(controlled by a CPU) to provide 100% disconnect if case of any 
battery fault.


Larry



On Sep 23, 2015, at 2:26 PM, William Miller > wrote:


Dear Fellow Wrenches

Below is a design conundrum that may resonate with some of you:

We are finalizing a design for an off-grid residential system.  The 
customer insist the PV should be on the roof and pre-installed a 
1-1/4” PVC conduit from his roof to a crawl space, in anticipation of 
a solar install.  This created real problems, because we all know we 
can’t pull PV source or output circuits in (or now, on)  the envelopes 
of habitable buildings.


There was no practical way to replace the PVC.  We contrived a method 
to sleeve ¾” liquid-tight through the 1-1/4” PVC to the crawl space, 
continuing on with EMT.  This is the largest metallic conduit we could 
fit.  The distance was greater than 10 feet so we couldn’t use EMT.  
Due to the conduit size restriction, we upgraded to Morningstar 600 
volt charge controllers, allowing us to reduce conductor size.


(As a sidebar, although the Morningstar is listed as a 600 volt charge 
controller, we have found no circumstance were we could take advantage 
of that high a voltage.  With the currently available high wattage 
modules, by the time we added enough in series to get to 600 volts, we 
were well beyond the wattage capabilities of the controller. For sake 
of design considerations, I suggest one regard these units as ~300 
volt charge controllers.)


We now have plans for 300 volt PV feeders running down an interior 
wall and under the house, with no roof-top disconnecting means.  It is 
my understanding none are required.  I am not comfortable with this.  
In this scenario, there is no safe way to replace either of the two 
Morningstar controllers. Should someone drill through or damage the 
EMT in the wall or under the floor, there would be no way to turn off 
the feeder.


I don’t like putting HU361RBs on a roof. They must remain vertical and 
so they stick up too high and are hard to provide mounting for. 
Sola-deck units are another option, but they require integrating with 
shingles, not practical on this job or many others.  I finally settled 
on a DC-Sunvolt PV-X16A-4X-RG disconnect as a possible solution.  At 
$216 it is not out of range.  The unit will provide means to turn off 
the feeders for service.  I will report back on my impressions of the 
unit.


To distill this scenario, I don’t believe the code requires a 
disconnect, but I feel morally obligated to install one.  I’d be 
interested in verification of the code interpretation and others 
response to similar situations.


I found no other options for rooftop disconnecting means that would be 
small, reasonably priced and not present a high profile.  If there are 
products I don’t know about, I would be most grateful to receive your 
input.


While researching the hardware I stumbled upon this article, linked 
below.  It seems to present a real dilemma, but I am not convinced. 
Please remain skeptical as you read.  It appears all of the links 
direct you to the same source.


https://www.linkedin.com/pulse/greatest-debacle-solar-pv-australias-rooftop-dc-isolator-lucas-sadler

Thanks again to all of you for helpful advice and expertise.  I 
learned about Sunvolt here, just one of many great suggestions.


Sincerely,

William Miller



Lic 773985
millersolar.com 
805-438-5600





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Re: [RE-wrenches] Rooftop DC disconnects

[William Miller]

Brian:

I agree 100%. Handling a tarp on a roof is impractical, ineffective and 
unreliable. Wind and slope are just two factors that increase danger and reduce 
reliability.

William



> On Sep 24, 2015, at 9:12 AM, Brian Mehalic  wrote:
> 
> I disagree about tarps. We've tested fully covered arrays (and small ones at 
> that) and still had what would be considered lethal levels of current and 
> voltage, even when using heavy, reflective tarps. And it can be very 
> difficult to ensure they stay in place, plus it's impractical for larger 
> arrays. 
> 
> Brian
> 
>> On Sep 24, 2015, at 6:31 AM, Jason Szumlanski 
>>  wrote:
>> 
>> "​In this scenario, there is no safe way to replace either of the two 
>> Morningstar controllers."
>> 
>> The BEST rooftop disconnect remains... a big thick tarp. Not totally 
>> practical in an emergency situation, but it is pretty fail safe. 
>> 
>> Unfortunately for emergency responders, that does not take care of the AC 
>> circuits in a microinverter or AC module system, but ideally the building 
>> main is shut down anyway, and the risk is the same as any other 240V 
>> equipment/appliance circuits.
>> 
>> ​Jason Szumlanski
>> 
>> 
>> 
>>> On Wed, Sep 23, 2015 at 4:26 PM, William Miller  
>>> wrote:
>>> Dear Fellow Wrenches
>>> 
>>>  
>>> 
>>> Below is a design conundrum that may resonate with some of you:
>>> 
>>>  
>>> 
>>> We are finalizing a design for an off-grid residential system.  The 
>>> customer insist the PV should be on the roof and pre-installed a 1-1/4” PVC 
>>> conduit from his roof to a crawl space, in anticipation of a solar install. 
>>>  This created real problems, because we all know we can’t pull PV source or 
>>> output circuits in (or now, on)  the envelopes of habitable buildings.
>>> 
>>>  
>>> 
>>> There was no practical way to replace the PVC.  We contrived a method to 
>>> sleeve ¾” liquid-tight through the 1-1/4” PVC to the crawl space, 
>>> continuing on with EMT.  This is the largest metallic conduit we could fit. 
>>>  The distance was greater than 10 feet so we couldn’t use EMT.  Due to the 
>>> conduit size restriction, we upgraded to Morningstar 600 volt charge 
>>> controllers, allowing us to reduce conductor size.
>>> 
>>>  
>>> 
>>> (As a sidebar, although the Morningstar is listed as a 600 volt charge 
>>> controller, we have found no circumstance were we could take advantage of 
>>> that high a voltage.  With the currently available high wattage modules, by 
>>> the time we added enough in series to get to 600 volts, we were well beyond 
>>> the wattage capabilities of the controller.  For sake of design 
>>> considerations, I suggest one regard these units as ~300 volt charge 
>>> controllers.)
>>> 
>>>  
>>> 
>>> We now have plans for 300 volt PV feeders running down an interior wall and 
>>> under the house, with no roof-top disconnecting means.  It is my 
>>> understanding none are required.  I am not comfortable with this. 
>>> 
>>> ​​In this scenario, there is no safe way to replace either of the two 
>>> Morningstar controllers. Should someone drill through or damage the EMT in 
>>> the wall or under the floor, there would be no way to turn off the feeder.
>>>  
>>> 
>>> I don’t like putting HU361RBs on a roof.  They must remain vertical and so 
>>> they stick up too high and are hard to provide mounting for.  Sola-deck 
>>> units are another option, but they require integrating with shingles, not 
>>> practical on this job or many others.  I finally settled on a DC-Sunvolt 
>>> PV-X16A-4X-RG disconnect as a possible solution.  At $216 it is not out of 
>>> range.  The unit will provide means to turn off the feeders for service.  I 
>>> will report back on my impressions of the unit.
>>> 
>>>  
>>> 
>>> To distill this scenario, I don’t believe the code requires a disconnect, 
>>> but I feel morally obligated to install one.  I’d be interested in 
>>> verification of the code interpretation and others response to similar 
>>> situations.
>>> 
>>>  
>>> 
>>> I found no other options for rooftop disconnecting means that would be 
>>> small, reasonably priced and not present a high profile.  If there are 
>>> products I don’t know about, I would be most grateful to receive your input.
>>> 
>>>  
>>> 
>>> While researching the hardware I stumbled upon this article, linked below.  
>>> It seems to present a real dilemma, but I am not convinced.  Please remain 
>>> skeptical as you read.  It appears all of the links direct you to the same 
>>> source.
>>> 
>>>  
>>> 
>>> https://www.linkedin.com/pulse/greatest-debacle-solar-pv-australias-rooftop-dc-isolator-lucas-sadler
>>> 
>>>  
>>> 
>>> Thanks again to all of you for helpful advice and expertise.  I learned 
>>> about Sunvolt here, just one of many great suggestions.
>>> 
>>>  
>>> 
>>> Sincerely,
>>> 
>>>  
>>> 
>>> William Miller
>>> 
>>>  
>>> 
>>>  
>>> 
>>> 
>>> Lic 773985
>>> millersolar.com
>>> 805-438-5600
>>> 
>> ___
>> List

Re: [RE-wrenches] Rooftop DC disconnects

[Lloyd Hoffstatter]

Wrenches,

UL has done testing on various materials for use as array covers, and lists 
their results. While perhaps not too practical as a means of shutting down a 
working system, this can be one of firefighters’ only effective methods when a 
fire has occurred and has damaged modules until PV pros arrive to disable 
system (UL tests have also shown destroyed modules still can produce high 
voltage).

Regards,
Lloyd Hoffstatter
NABCEP PV Installer
NY-Sun instructor



From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf 
Of William Miller
Sent: Thursday, September 24, 2015 1:06 PM
To: RE-wrenches 
Subject: Re: [RE-wrenches] Rooftop DC disconnects

Brian:

I agree 100%. Handling a tarp on a roof is impractical, ineffective and 
unreliable. Wind and slope are just two factors that increase danger and reduce 
reliability.

William


On Sep 24, 2015, at 9:12 AM, Brian Mehalic 
mailto:br...@solarenergy.org>> wrote:
I disagree about tarps. We've tested fully covered arrays (and small ones at 
that) and still had what would be considered lethal levels of current and 
voltage, even when using heavy, reflective tarps. And it can be very difficult 
to ensure they stay in place, plus it's impractical for larger arrays.

Brian

On Sep 24, 2015, at 6:31 AM, Jason Szumlanski 
mailto:ja...@floridasolardesigngroup.com>> 
wrote:
"​In this scenario, there is no safe way to replace either of the two 
Morningstar controllers."

The BEST rooftop disconnect remains... a big thick tarp. Not totally practical 
in an emergency situation, but it is pretty fail safe.

Unfortunately for emergency responders, that does not take care of the AC 
circuits in a microinverter or AC module system, but ideally the building main 
is shut down anyway, and the risk is the same as any other 240V 
equipment/appliance circuits.

​Jason Szumlanski



On Wed, Sep 23, 2015 at 4:26 PM, William Miller 
mailto:will...@millersolar.com>> wrote:
Dear Fellow Wrenches

Below is a design conundrum that may resonate with some of you:

We are finalizing a design for an off-grid residential system.  The customer 
insist the PV should be on the roof and pre-installed a 1-1/4” PVC conduit from 
his roof to a crawl space, in anticipation of a solar install.  This created 
real problems, because we all know we can’t pull PV source or output circuits 
in (or now, on)  the envelopes of habitable buildings.

There was no practical way to replace the PVC.  We contrived a method to sleeve 
¾” liquid-tight through the 1-1/4” PVC to the crawl space, continuing on with 
EMT.  This is the largest metallic conduit we could fit.  The distance was 
greater than 10 feet so we couldn’t use EMT.  Due to the conduit size 
restriction, we upgraded to Morningstar 600 volt charge controllers, allowing 
us to reduce conductor size.

(As a sidebar, although the Morningstar is listed as a 600 volt charge 
controller, we have found no circumstance were we could take advantage of that 
high a voltage.  With the currently available high wattage modules, by the time 
we added enough in series to get to 600 volts, we were well beyond the wattage 
capabilities of the controller.  For sake of design considerations, I suggest 
one regard these units as ~300 volt charge controllers.)

We now have plans for 300 volt PV feeders running down an interior wall and 
under the house, with no roof-top disconnecting means.  It is my understanding 
none are required.  I am not comfortable with this.
​​
In this scenario, there is no safe way to replace either of the two Morningstar 
controllers. Should someone drill through or damage the EMT in the wall or 
under the floor, there would be no way to turn off the feeder.

I don’t like putting HU361RBs on a roof.  They must remain vertical and so they 
stick up too high and are hard to provide mounting for.  Sola-deck units are 
another option, but they require integrating with shingles, not practical on 
this job or many others.  I finally settled on a DC-Sunvolt PV-X16A-4X-RG 
disconnect as a possible solution.  At $216 it is not out of range.  The unit 
will provide means to turn off the feeders for service.  I will report back on 
my impressions of the unit.

To distill this scenario, I don’t believe the code requires a disconnect, but I 
feel morally obligated to install one.  I’d be interested in verification of 
the code interpretation and others response to similar situations.

I found no other options for rooftop disconnecting means that would be small, 
reasonably priced and not present a high profile.  If there are products I 
don’t know about, I would be most grateful to receive your input.

While researching the hardware I stumbled upon this article, linked below.  It 
seems to present a real dilemma, but I am not convinced.  Please remain 
skeptical as you read.  It appears all of the links direct you to the same 
source.

https://www.linkedin.com/pulse/greatest-debacle-solar-pv-australias-rooftop-dc-isolator-lucas-sad

Re: [RE-wrenches] Rooftop DC disconnects

[Starlight Solar Power Systems]

Ray,

UL508 for sure but look here: http://gigavac.com/catalog/pp/hx.html

Larry 

On Sep 24, 2015, at 11:03 AM, Ray Walters  wrote:

….  Is the Gigavac UL listed?
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer, 
Licensed Master Electrician
Solar Design Engineer
303 505-8760

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Re: [RE-wrenches] Rooftop DC disconnects

[Jason Szumlanski]

Interesting. I'd like to get a hold of those test results.

It is not always practical, but I have never had an issue using opaque
black-out type tarps (of course - testing for voltage is a critical safety
step). The flimsy blue stuff will definitely not work. At one time I had a
sports field cover, but it was too heavy to manage. Then again, we deal
with low-slope roofs around here, making roofs easily walk-able. I
challenge the assertion that it's ineffective and unreliable. Practical?
Judgment call. How effective is a disconnect at de-energizing the
conductors between the array and the disconnect itself?

There are many module and inverter manufactures that prescribe opaque
covers while conducting wiring operations in their manuals. Here are some
other resources that point to this same method for "shutting down a PV
system" including:

Home Power
http://www.homepower.com/articles/solar-electricity/equipment-products/pv-safety-and-firefighting

Fire Engineering:
http://www.fireengineering.com/articles/print/volume-162/issue-5/features/solar-electric-systems-and-firefighter-safety.html



On Thu, Sep 24, 2015 at 2:19 PM, Lloyd Hoffstatter <
lhoffstat...@sunstruckconsulting.com> wrote:

> Wrenches,
>
>
>
> UL has done testing on various materials for use as array covers, and
> lists their results. While perhaps not too practical as a means of shutting
> down a working system, this can be one of firefighters’ only effective
> methods when a fire has occurred and has damaged modules until PV pros
> arrive to disable system (UL tests have also shown destroyed modules still
> can produce high voltage).
>
>
>
> Regards,
>
> Lloyd Hoffstatter
>
> NABCEP PV Installer
>
> NY-Sun instructor
>
>
>
>
>
>
>
> *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On
> Behalf Of *William Miller
> *Sent:* Thursday, September 24, 2015 1:06 PM
> *To:* RE-wrenches 
> *Subject:* Re: [RE-wrenches] Rooftop DC disconnects
>
>
>
> Brian:
>
>
>
> I agree 100%. Handling a tarp on a roof is impractical, ineffective and
> unreliable. Wind and slope are just two factors that increase danger and
> reduce reliability.
>
>
>
> William
>
>
> On Sep 24, 2015, at 9:12 AM, Brian Mehalic  wrote:
>
> I disagree about tarps. We've tested fully covered arrays (and small ones
> at that) and still had what would be considered lethal levels of current
> and voltage, even when using heavy, reflective tarps. And it can be very
> difficult to ensure they stay in place, plus it's impractical for larger
> arrays.
>
> Brian
>
>
> On Sep 24, 2015, at 6:31 AM, Jason Szumlanski <
> ja...@floridasolardesigngroup.com> wrote:
>
> "​In this scenario, there is no safe way to replace either of the two
> Morningstar controllers."
>
>
>
> The BEST rooftop disconnect remains... a big thick tarp. Not totally
> practical in an emergency situation, but it is pretty fail safe.
>
>
>
> Unfortunately for emergency responders, that does not take care of the AC
> circuits in a microinverter or AC module system, but ideally the building
> main is shut down anyway, and the risk is the same as any other 240V
> equipment/appliance circuits.
>
>
>
> ​Jason Szumlanski
>
>
>
>
>
>
>
> On Wed, Sep 23, 2015 at 4:26 PM, William Miller 
> wrote:
>
> Dear Fellow Wrenches
>
>
>
> Below is a design conundrum that may resonate with some of you:
>
>
>
> We are finalizing a design for an off-grid residential system.  The
> customer insist the PV should be on the roof and pre-installed a 1-1/4” PVC
> conduit from his roof to a crawl space, in anticipation of a solar
> install.  This created real problems, because we all know we can’t pull PV
> source or output circuits in (or now, on)  the envelopes of habitable
> buildings.
>
>
>
> There was no practical way to replace the PVC.  We contrived a method to
> sleeve ¾” liquid-tight through the 1-1/4” PVC to the crawl space,
> continuing on with EMT.  This is the largest metallic conduit we could
> fit.  The distance was greater than 10 feet so we couldn’t use EMT.  Due to
> the conduit size restriction, we upgraded to Morningstar 600 volt charge
> controllers, allowing us to reduce conductor size.
>
>
>
> (As a sidebar, although the Morningstar is listed as a 600 volt charge
> controller, we have found no circumstance were we could take advantage of
> that high a voltage.  With the currently available high wattage modules, by
> the time we added enough in series to get to 600 volts, we were well beyond
> the wattage capabilities of the controller.  For sake of design
> considerations, I suggest one regard these units as ~300 volt charge
> controllers.)
>
>
>
> We now have plans for 300 volt PV feeders running down an interior wall
> and under the house, with no roof-top disconnecting means.  It is my
> understanding none are required.  I am not comfortable with this.
>
> ​​
>
> In this scenario, there is no safe way to replace either of the two
> Morningstar controllers. Should someone drill through or damage the EMT in
> the

[RE-wrenches] Xantrex TR series inverter

[RM You]

Hi guys, I recently took a Xantrex TR series inverter on trade from a customer 
who is upgrading. According to the inverter spec sheet the inverter is capable 
of equalizing the batteries but I can’t figure out how. The manual says 
absolutely nothing about how to invoke equalizing, just shows the equalize 
voltage. I have not been a big Xantrex fan so have sold very few of their 
inverters over the years. Can anyone tell me the secret to making this beast go 
into equalize mode? There is a remote for it but all it does is turn the unit 
on and off. On the older Trace DR inverters equalize is clearly shown on the 
Battery Type Selector on the front of the inverter.

This unit is a Xantrex TR 2412-120-60 but the same info would apply to 1512 up 
to the 3624 of the same series. Thanks for any help!

Ron Young



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Re: [RE-wrenches] Rooftop DC disconnects

[Glenn Burt]

http://websites.firecompanies.com/njiaai/files/2014/04/PV-FF_SafetyFinalReport.pdf

 

I think this is the report Lloyd referred to.

 

I used it this spring during a firefighter training class I taught. It has a 
lot of interesting information.

 

-Glenn

 

From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf 
Of Jason Szumlanski
Sent: Thursday, September 24, 2015 2:26 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Rooftop DC disconnects

 

Interesting. I'd like to get a hold of those test results.

 

It is not always practical, but I have never had an issue using opaque 
black-out type tarps (of course - testing for voltage is a critical safety 
step). The flimsy blue stuff will definitely not work. At one time I had a 
sports field cover, but it was too heavy to manage. Then again, we deal with 
low-slope roofs around here, making roofs easily walk-able. I challenge the 
assertion that it's ineffective and unreliable. Practical? Judgment call. How 
effective is a disconnect at de-energizing the conductors between the array and 
the disconnect itself?

 

There are many module and inverter manufactures that prescribe opaque covers 
while conducting wiring operations in their manuals. Here are some other 
resources that point to this same method for "shutting down a PV system" 
including:

 

Home Power

http://www.homepower.com/articles/solar-electricity/equipment-products/pv-safety-and-firefighting

 

Fire Engineering:

http://www.fireengineering.com/articles/print/volume-162/issue-5/features/solar-electric-systems-and-firefighter-safety.html

 




 

On Thu, Sep 24, 2015 at 2:19 PM, Lloyd Hoffstatter 
 wrote:

Wrenches,

 

UL has done testing on various materials for use as array covers, and lists 
their results. While perhaps not too practical as a means of shutting down a 
working system, this can be one of firefighters’ only effective methods when a 
fire has occurred and has damaged modules until PV pros arrive to disable 
system (UL tests have also shown destroyed modules still can produce high 
voltage).

 

Regards,

Lloyd Hoffstatter

NABCEP PV Installer

NY-Sun instructor

 

 

 

From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf 
Of William Miller
Sent: Thursday, September 24, 2015 1:06 PM
To: RE-wrenches 
Subject: Re: [RE-wrenches] Rooftop DC disconnects

 

Brian:

 

I agree 100%. Handling a tarp on a roof is impractical, ineffective and 
unreliable. Wind and slope are just two factors that increase danger and reduce 
reliability.

 

William


On Sep 24, 2015, at 9:12 AM, Brian Mehalic  wrote:

I disagree about tarps. We've tested fully covered arrays (and small ones at 
that) and still had what would be considered lethal levels of current and 
voltage, even when using heavy, reflective tarps. And it can be very difficult 
to ensure they stay in place, plus it's impractical for larger arrays. 

Brian


On Sep 24, 2015, at 6:31 AM, Jason Szumlanski 
 wrote:

"​In this scenario, there is no safe way to replace either of the two 
Morningstar controllers."

 

The BEST rooftop disconnect remains... a big thick tarp. Not totally practical 
in an emergency situation, but it is pretty fail safe. 

 

Unfortunately for emergency responders, that does not take care of the AC 
circuits in a microinverter or AC module system, but ideally the building main 
is shut down anyway, and the risk is the same as any other 240V 
equipment/appliance circuits.

 

​Jason Szumlanski

 

 

 

On Wed, Sep 23, 2015 at 4:26 PM, William Miller  wrote:

Dear Fellow Wrenches

 

Below is a design conundrum that may resonate with some of you:

 

We are finalizing a design for an off-grid residential system.  The customer 
insist the PV should be on the roof and pre-installed a 1-1/4” PVC conduit from 
his roof to a crawl space, in anticipation of a solar install.  This created 
real problems, because we all know we can’t pull PV source or output circuits 
in (or now, on)  the envelopes of habitable buildings.

 

There was no practical way to replace the PVC.  We contrived a method to sleeve 
¾” liquid-tight through the 1-1/4” PVC to the crawl space, continuing on with 
EMT.  This is the largest metallic conduit we could fit.  The distance was 
greater than 10 feet so we couldn’t use EMT.  Due to the conduit size 
restriction, we upgraded to Morningstar 600 volt charge controllers, allowing 
us to reduce conductor size.

 

(As a sidebar, although the Morningstar is listed as a 600 volt charge 
controller, we have found no circumstance were we could take advantage of that 
high a voltage.  With the currently available high wattage modules, by the time 
we added enough in series to get to 600 volts, we were well beyond the wattage 
capabilities of the controller.  For sake of design considerations, I suggest 
one regard these units as ~300 volt charge controllers.)

 

We now have plans for 300 volt PV feeders running down an interior wall and 
under the h

Re: [RE-wrenches] Rooftop DC disconnects

[Chris Mason]

I'm not sure I understand this issue. The Morningstar 600V comes with a
disconnect built in, so everything downstream is isolated. Upstream, in the
rare case you need to replace the Morningstar, turn it off, pop out the
fuses in the combiner and work away. If you have a single string
application, unplug an MC4 connector.

On Thu, Sep 24, 2015 at 8:31 AM, Jason Szumlanski <
ja...@floridasolardesigngroup.com> wrote:

> "​In this scenario, there is no safe way to replace either of the two
> Morningstar controllers."
>
> The BEST rooftop disconnect remains... a big thick tarp. Not totally
> practical in an emergency situation, but it is pretty fail safe.
>
> Unfortunately for emergency responders, that does not take care of the AC
> circuits in a microinverter or AC module system, but ideally the building
> main is shut down anyway, and the risk is the same as any other 240V
> equipment/appliance circuits.
>
> ​Jason Szumlanski
>
>
>
> On Wed, Sep 23, 2015 at 4:26 PM, William Miller 
> wrote:
>
>> Dear Fellow Wrenches
>>
>>
>>
>> Below is a design conundrum that may resonate with some of you:
>>
>>
>>
>> We are finalizing a design for an off-grid residential system.  The
>> customer insist the PV should be on the roof and pre-installed a 1-1/4” PVC
>> conduit from his roof to a crawl space, in anticipation of a solar
>> install.  This created real problems, because we all know we can’t pull PV
>> source or output circuits in (or now, on)  the envelopes of habitable
>> buildings.
>>
>>
>>
>> There was no practical way to replace the PVC.  We contrived a method to
>> sleeve ¾” liquid-tight through the 1-1/4” PVC to the crawl space,
>> continuing on with EMT.  This is the largest metallic conduit we could
>> fit.  The distance was greater than 10 feet so we couldn’t use EMT.  Due to
>> the conduit size restriction, we upgraded to Morningstar 600 volt charge
>> controllers, allowing us to reduce conductor size.
>>
>>
>>
>> (As a sidebar, although the Morningstar is listed as a 600 volt charge
>> controller, we have found no circumstance were we could take advantage of
>> that high a voltage.  With the currently available high wattage modules, by
>> the time we added enough in series to get to 600 volts, we were well beyond
>> the wattage capabilities of the controller.  For sake of design
>> considerations, I suggest one regard these units as ~300 volt charge
>> controllers.)
>>
>>
>>
>> We now have plans for 300 volt PV feeders running down an interior wall
>> and under the house, with no roof-top disconnecting means.  It is my
>> understanding none are required.  I am not comfortable with this.
>> ​​
>> In this scenario, there is no safe way to replace either of the two
>> Morningstar controllers. Should someone drill through or damage the EMT in
>> the wall or under the floor, there would be no way to turn off the feeder.
>>
>>
>>
>> I don’t like putting HU361RBs on a roof.  They must remain vertical and
>> so they stick up too high and are hard to provide mounting for.  Sola-deck
>> units are another option, but they require integrating with shingles, not
>> practical on this job or many others.  I finally settled on a DC-Sunvolt
>> PV-X16A-4X-RG disconnect as a possible solution.  At $216 it is not out of
>> range.  The unit will provide means to turn off the feeders for service.  I
>> will report back on my impressions of the unit.
>>
>>
>>
>> To distill this scenario, I don’t believe the code requires a disconnect,
>> but I feel morally obligated to install one.  I’d be interested in
>> verification of the code interpretation and others response to similar
>> situations.
>>
>>
>>
>> I found no other options for rooftop disconnecting means that would be
>> small, reasonably priced and not present a high profile.  If there are
>> products I don’t know about, I would be most grateful to receive your input.
>>
>>
>>
>> While researching the hardware I stumbled upon this article, linked
>> below.  It seems to present a real dilemma, but I am not convinced.  Please
>> remain skeptical as you read.  It appears all of the links direct you to
>> the same source.
>>
>>
>>
>>
>> https://www.linkedin.com/pulse/greatest-debacle-solar-pv-australias-rooftop-dc-isolator-lucas-sadler
>>
>>
>>
>> Thanks again to all of you for helpful advice and expertise.  I learned
>> about Sunvolt here, just one of many great suggestions.
>>
>>
>>
>> Sincerely,
>>
>>
>>
>> William Miller
>>
>>
>>
>>
>>
>> [image: Gradient Cap_mini]
>> Lic 773985
>> millersolar.com 
>> 805-438-5600
>>
>>
>>
>
> ___
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Re: [RE-wrenches] Xantrex TR series inverter

[RM You]

Answered my own question, found the pinhole opening on the front of the 
inverter to start EQ.

Ron

> On Sep 24, 2015, at 3:13 PM, RM You  wrote:
> 
> Hi guys, I recently took a Xantrex TR series inverter on trade from a 
> customer who is upgrading. According to the inverter spec sheet the inverter 
> is capable of equalizing the batteries but I can’t figure out how. The manual 
> says absolutely nothing about how to invoke equalizing, just shows the 
> equalize voltage. I have not been a big Xantrex fan so have sold very few of 
> their inverters over the years. Can anyone tell me the secret to making this 
> beast go into equalize mode? There is a remote for it but all it does is turn 
> the unit on and off. On the older Trace DR inverters equalize is clearly 
> shown on the Battery Type Selector on the front of the inverter.
> 
> This unit is a Xantrex TR 2412-120-60 but the same info would apply to 1512 
> up to the 3624 of the same series. Thanks for any help!
> 
> Ron Young
> 
> 
> 

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Re: [RE-wrenches] Rooftop DC disconnects

[Lloyd Hoffstatter]

Thanks Glenn, that’s the one – there are also some UL videos showing the tests 
and the results, sobering yet valuable information.

Under the NY-Sun program, we are both training and listening to firefighters in 
the attempt to provide practical information for working around PV systems and 
ultimately how to provide safety in the aftermath of an event.  As shown in the 
UL report,  4 or 6 mill black plastic is opaque enough to provide voltage 
reduction to safe levels when fully covering the array.  For fire companies 
that already carry clear plastic and clamps to cover venting skylights, the 
switch to black is a simple and inexpensive example of same.

Best regards,

Lloyd Hoffstatter

From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf 
Of Glenn Burt
Sent: Thursday, September 24, 2015 6:08 PM
To: 'RE-wrenches' 
Subject: Re: [RE-wrenches] Rooftop DC disconnects

http://websites.firecompanies.com/njiaai/files/2014/04/PV-FF_SafetyFinalReport.pdf

I think this is the report Lloyd referred to.

I used it this spring during a firefighter training class I taught. It has a 
lot of interesting information.

-Glenn

From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf 
Of Jason Szumlanski
Sent: Thursday, September 24, 2015 2:26 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Rooftop DC disconnects

Interesting. I'd like to get a hold of those test results.

It is not always practical, but I have never had an issue using opaque 
black-out type tarps (of course - testing for voltage is a critical safety 
step). The flimsy blue stuff will definitely not work. At one time I had a 
sports field cover, but it was too heavy to manage. Then again, we deal with 
low-slope roofs around here, making roofs easily walk-able. I challenge the 
assertion that it's ineffective and unreliable. Practical? Judgment call. How 
effective is a disconnect at de-energizing the conductors between the array and 
the disconnect itself?

There are many module and inverter manufactures that prescribe opaque covers 
while conducting wiring operations in their manuals. Here are some other 
resources that point to this same method for "shutting down a PV system" 
including:

Home Power
http://www.homepower.com/articles/solar-electricity/equipment-products/pv-safety-and-firefighting

Fire Engineering:
http://www.fireengineering.com/articles/print/volume-162/issue-5/features/solar-electric-systems-and-firefighter-safety.html



On Thu, Sep 24, 2015 at 2:19 PM, Lloyd Hoffstatter 
mailto:lhoffstat...@sunstruckconsulting.com>>
 wrote:
Wrenches,

UL has done testing on various materials for use as array covers, and lists 
their results. While perhaps not too practical as a means of shutting down a 
working system, this can be one of firefighters’ only effective methods when a 
fire has occurred and has damaged modules until PV pros arrive to disable 
system (UL tests have also shown destroyed modules still can produce high 
voltage).

Regards,
Lloyd Hoffstatter
NABCEP PV Installer
NY-Sun instructor



From: RE-wrenches 
[mailto:re-wrenches-boun...@lists.re-wrenches.org]
 On Behalf Of William Miller
Sent: Thursday, September 24, 2015 1:06 PM
To: RE-wrenches 
mailto:re-wrenches@lists.re-wrenches.org>>
Subject: Re: [RE-wrenches] Rooftop DC disconnects

Brian:

I agree 100%. Handling a tarp on a roof is impractical, ineffective and 
unreliable. Wind and slope are just two factors that increase danger and reduce 
reliability.

William

On Sep 24, 2015, at 9:12 AM, Brian Mehalic 
mailto:br...@solarenergy.org>> wrote:
I disagree about tarps. We've tested fully covered arrays (and small ones at 
that) and still had what would be considered lethal levels of current and 
voltage, even when using heavy, reflective tarps. And it can be very difficult 
to ensure they stay in place, plus it's impractical for larger arrays.

Brian

On Sep 24, 2015, at 6:31 AM, Jason Szumlanski 
mailto:ja...@floridasolardesigngroup.com>> 
wrote:
"​In this scenario, there is no safe way to replace either of the two 
Morningstar controllers."

The BEST rooftop disconnect remains... a big thick tarp. Not totally practical 
in an emergency situation, but it is pretty fail safe.

Unfortunately for emergency responders, that does not take care of the AC 
circuits in a microinverter or AC module system, but ideally the building main 
is shut down anyway, and the risk is the same as any other 240V 
equipment/appliance circuits.

​Jason Szumlanski



On Wed, Sep 23, 2015 at 4:26 PM, William Miller 
mailto:will...@millersolar.com>> wrote:
Dear Fellow Wrenches

Below is a design conundrum that may resonate with some of you:

We are finalizing a design for an off-grid residential system.  The customer 
insist the PV should be on the roof and pre-installed a 1-1/4” PVC conduit from 
his roof to a crawl space, in anticipation of a solar install.  This created 
real problems, because we all know 

Re: [RE-wrenches] Rooftop DC disconnects

[Starlight Solar Power Systems]

William, Ray, 

I asked Midnite about using the Aux circuit for control for ground or arc 
faults. They said this will (should) be added on the next firmware update. This 
means if an arc fault is detected, the Classic will shut down AND conductors 
leaving the array would be de-energized by switching off the HV relay. All 
automatically. A second relay could be connected to the battery for total 
system shutdown. Should be easy to build a circuit to re-energize everything 
after a fault.

Wouldn't this automatic method be better than waiting for someone to throw a 
switch to shut things down? You would have to run the low voltage control wire 
and perhaps put the relays in an enclosure. A disconnect switch could be in 
series for manual shutdown. What am I missing?

Larry   




On Sep 24, 2015, at 11:03 AM, Ray Walters mailto:r...@solarray.com>> wrote:

The other option is Midnite Solar's remote controlled breakers or combiner 
boxes.  They make up to a 250 amp breaker, but I found on large battery systems 
that we need some thing larger. Colorado is now requiring Rapid Disconnect for 
the batteries as well, which is NOT the original intent of that article.  Is 
the Gigavac UL listed?
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer, 
Licensed Master Electrician
Solar Design Engineer
303 505-8760
On 9/24/2015 10:45 AM, Starlight Solar Power Systems wrote:
> William and Wrenches, 
> 
> I have pondered situations like this one and wonder the following: If a high 
> voltage DC solenoid were placed at the PV array and the coil was controlled 
> by an arc fault detector along with a means of manually disconnecting, would 
> that not work to satisfy shut down requirements and safety concerns? 
> 
> We have been using 350A, 800 volt solenoids from Gigavac in our lithium 
> battery system on both the positive and negative terminals (controlled by a 
> CPU) to provide 100% disconnect if case of any battery fault. 
> 
> Larry
> 
> 
> 
> On Sep 23, 2015, at 2:26 PM, William Miller < 
> will...@millersolar.com 
> > wrote:
> 
> Dear Fellow Wrenches
>  
> Below is a design conundrum that may resonate with some of you:
>  
> We are finalizing a design for an off-grid residential system.  The customer 
> insist the PV should be on the roof and pre-installed a 1-1/4” PVC conduit 
> from his roof to a crawl space, in anticipation of a solar install.  This 
> created real problems, because we all know we can’t pull PV source or output 
> circuits in (or now, on)  the envelopes of habitable buildings.
>  
> There was no practical way to replace the PVC.  We contrived a method to 
> sleeve ¾” liquid-tight through the 1-1/4” PVC to the crawl space, continuing 
> on with EMT.  This is the largest metallic conduit we could fit.  The 
> distance was greater than 10 feet so we couldn’t use EMT.  Due to the conduit 
> size restriction, we upgraded to Morningstar 600 volt charge controllers, 
> allowing us to reduce conductor size.
>  
> (As a sidebar, although the Morningstar is listed as a 600 volt charge 
> controller, we have found no circumstance were we could take advantage of 
> that high a voltage.  With the currently available high wattage modules, by 
> the time we added enough in series to get to 600 volts, we were well beyond 
> the wattage capabilities of the controller.  For sake of design 
> considerations, I suggest one regard these units as ~300 volt charge 
> controllers.)
>  
> We now have plans for 300 volt PV feeders running down an interior wall and 
> under the house, with no roof-top disconnecting means.  It is my 
> understanding none are required.  I am not comfortable with this.  In this 
> scenario, there is no safe way to replace either of the two Morningstar 
> controllers. Should someone drill through or damage the EMT in the wall or 
> under the floor, there would be no way to turn off the feeder.
>  
> I don’t like putting HU361RBs on a roof.  They must remain vertical and so 
> they stick up too high and are hard to provide mounting for.  Sola-deck units 
> are another option, but they require integrating with shingles, not practical 
> on this job or many others.  I finally settled on a DC-Sunvolt PV-X16A-4X-RG 
> disconnect as a possible solution.  At $216 it is not out of range.  The unit 
> will provide means to turn off the feeders for service.  I will report back 
> on my impressions of the unit.
>  
> To distill this scenario, I don’t believe the code requires a disconnect, but 
> I feel morally obligated to install one.  I’d be interested in verification 
> of the code interpretation and others response to similar situations.
>  
> I found no other options for rooftop disconnecting means that would be small, 
> reasonably priced and not present a high profile.  If there are products I 
> don’t know about, I would be most grateful to receive your input.
>  
> While researching the hardware I stumbled upon this arti

[RE-wrenches] Pika inverter

[Howie Michaelson]

Has anyone have any experience or even knowledge of the Pika products?
http://www.pika-energy.com/
Looks like a direct competitor to SolarEdge. Is it actually in the field or in 
production?
Thanks,Howie

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Re: [RE-wrenches] Pika inverter

[ryan.hark...@energycraft.com]

Howie,

We've installed some Pika systems, and been impressed with the quality and 
service. (It is easy to get sales, shipping, engineers on the phone). 
Relatively new company, but with ties back to southwest windpower days.  I'm 
guessing you found them when looking at possible Tesla or other GTWB options.  
Haven't used their newest "islanding" inverter yet.

It is pretty awesome how they have designed the Inverter with what they call 
REBUS.  And accepts multiple DC inputs.  So we've got DC from their turbine, 
and you can add 8 60cell PV modules all to one inverter.  The PV does still 
have MPPT via their Pv link, which then lands on the rebus DC inputs of the 
inverter.

Wifi built in is nice too.  

Not sure if they have any of their new islanding inverters in the field yet or 
not.


Ryan Harkins


> On Sep 24, 2015, at 9:30 PM, Howie Michaelson  wrote:
> 
> Has anyone have any experience or even knowledge of the Pika products?
> 
> http://www.pika-energy.com/
> 
> Looks like a direct competitor to SolarEdge. Is it actually in the field or 
> in production?
> 
> Thanks,
> Howie
> 
> 
> Sent from my phone
> ___
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