Re: [RE-wrenches] Rapid Shutdown Compliance

[Jerry Shafer]

Wrenches
We are taking two very different issues and mixing them together. RSD and
Arc-fault are different, arc fault will and does prevent fires, RSD was
brought out of the need to vent a roof that even with the meter pulled have
500 volts and resulted shocks to fire fighters by cutting into roofs or
nearby conduite. This is fact not conjecture.
Arc fault is a fire preventer but requires nothing on the roof when using
string level inverters. Now both RSD and arc-fault in off grid increase the
complexity but the new charge controllers fit the arc and Tigo fixes the
RSD issues.
I know everyone of you learned to use a smart phone and can now adapt again
to this new tech, we have to be leaders in this industry and not well you
know.
Jerry
NABCEP PV Inspector.
Been in this industry since 1978

On Wed, Apr 29, 2020, 6:57 PM Jay  wrote:

> Hi Drake
>
> I will disagree, there have been many roof top fires.
>
> But regardless we have to do these new regulations and I for one welcome
> the safety.
>
> The main issue is accessing the faulty/suspect component under the module
> possibly requiring removing multiple modules, a slow and expensive process.
>
> My technique is to install the MLPE at the edges of the array, using wire
> extensions. That way at most I have to remove a single module.  And Im
> working on a drop bracket which would allow better cooling and easier
> access without module removal to the MLPE, greatly reducing time to swap.
>
> Jay
>
> Peltz Power.
>
>
>
>
>
> On Apr 29, 2020, at 7:59 AM, drake.chamber...@redwoodalliance.org wrote:
>
> 
>
> Clearly, rapid shutdown increases cost and reduces reliability. Given the
> excellent safety record of PV, prior to rapid shutdown being required, it
> is unnecessary. The few anecdotal incidents of PV fires were not enough to
> justify the requirement, especially on smaller systems.
>
> According to a friend who worked for a local installation company that
> went under, a big part of the reason for their failure was the chronic
> replacement of microinverters and optimizers.
>
> What steps can be taken to create some balance in the rapid shutdown
> requirements that are in the NEC?
>
>
> ---
>
>
>
> On 2020-04-29 07:27, Sky Sims wrote:
>
> So far rapid shutdown has been a nightmare. It's added a lot of cost for
> no measurable benefit.
> Using always off devices like midnight solar and Tigo makes it impossible
> to test open circuit voltages. Which opens the door to tons of problems
> when commissioning systems.
> Also we've been trying out midnight Solar's product and have had an absurd
> failure rate. Which means lots of truck rolls and troubleshooting and
> system downtime. They send replacement product but they aren't paying for
> the lost weeks of productivity.
> We have Tigo product in hand and are deciding which project to try it on.
> But our big concern about using it is not only the inability to confirm
> open circuit voltage of the strings but also the way panels bypass if the
> device doesn't allow the panel to connect properly. Both of these features
> are a recipe for problems and potential troubleshooting nightmares. The
> warranty from Tigo doesn't cover our expense if the product fails. And
> that's really what our reservations about the product boil down to right
> now. If we're on a job with 50 units and one fails, the contractor or the
> homeowner will be the ones eating the expense of finding it and replacing
> it. There has to be a better option.
>
> Sky Sims
> Https://EcologicalSystems.biz
>
> On Apr 28, 2020, at 7:46 PM, Corey Shalanski  wrote:
>
> Now that 690.12 of the *NEC* 2017 has been in effect for several years, I
> am curious how designers and installers are meeting the associated
> requirements with string inverter-based systems (*not* considering
> microinverters or DC optimizers). I am generally a fan of the KISS
> principle, and as best I can determine the *Tigo* TS4-F device is one of
> the simplest options currently available on the market. What are others
> finding?
>
> I'd love to hear about favored options for complying with rapid shutdown.
> Any success stories? or better yet, any early failures?
>
> --
> Corey Shalanski
> Jah Light Solar
> Portland, Jamaica
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Re: [RE-wrenches] Rapid Shutdown Compliance

[drake . chamberlin]

Rapid Shutdown does not prevent fires; it was originally drafted to
allow firefighters to vent a roof without being hindered by energized PV
arrays. This rule was expanded to include other DC wiring from PV
sources. 


As for PV safety, I'd like to see some significant, statistical evidence
that shows there is a major fire danger from PV relative to other
sources. A fire from a solar array gets a lot more press than one from a
gas leak, bad wiring or an ash tray emptied into a wastepaper basket. 


Large public buildings should have all the protection that is available.
Does one size fit all? 


Would it be reasonable to allow residential installations under 12 kW,
with 1/4 of the roof adjacent to the array available for venting, to be
excepted from 690.12? What about sparsely occupied commercial buildings
with ample roof area open for ventilation?   


Many of us have chosen to work with renewable energy technology to
lessen the harms caused by fossil fuel extraction and combustion. The
need for non-carbon based energy sources has become extremely clear. 


The old string inverters still chug along year after year, with little
or no maintenance. Someone must pay for the ongoing maintenance of
module level electronics. Dependable string inverter systems should be
allowed unless statically significant danger can be demonstrated. 


Drake

---

On 2020-04-29 16:01, Jason Szumlanski wrote:

I have been to several PV fires for string inverter systems, both commercial and residential, and have seen many DC systems at serious risk of fires or in various stages of melted insulation and connectors. Most of these systems have exhibited good to excellent workmanship. Things just went wrong. Some were traceable to animal damage, wind, or other unmitigated factors, and some were unexplained. I disagree that there isn't justification for rapid shutdown.  

In my opinion, what we need is some additional innovation and competition in the MLPE space. Reliability is clearly a key factor, but there is no denying that MLPE has added safety benefits among other benefits. And if you do enough volume and set up your business for efficiency (standardization of product offerings), MLPE isn't much more expensive. It becomes a negligible cost relative to the benefit. The value proposition is easy to convey. There are limits to this, but for the majority of residential and small commercial installations, MLPE has become the de facto standard around here. String inverters are dinos, and replacing 8-12 year old transformer based inverters is many times more annoying than some MLPE swaps. I will admit that the roofs around here are pretty easy to walk, so that is a factor that might not apply to you. 

If you go under due to manufacturer product failures, you are not writing your contracts right or not charging enough for service issues beyond your control. I believe that's a red herring. You might suffer some reputation damage, but for someone that has been installing MLPE for over a decade, that is totally manageable. Consumers find a service call to replace MLPE a LOT more palatable than a surprise inverter replacement that could cost thousands of dollars. People just don't plan for that. 

Regarding rapid shutdown devices, I have also come across a few that "someone" has bypassed around here. I don't know if they were never installed properly or disabled/bypassed due to failure. It seemed suspicious to me at the time. I remember that it made me wonder what good is a rapid shutdown device if it is easily defeated? That's another argument for MLPE. It has pretty failsafe MLPE functionality. 

Jason Szumlanski 
Florida Solar Design Group 

On Wed, Apr 29, 2020 at 10:59 AM  wrote: 

Clearly, rapid shutdown increases cost and reduces reliability. Given the excellent safety record of PV, prior to rapid shutdown being required, it is unnecessary. The few anecdotal incidents of PV fires were not enough to justify the requirement, especially on smaller systems. 

According to a friend who worked for a local installation company that went under, a big part of the reason for their failure was the chronic replacement of microinverters and optimizers. 

What steps can be taken to create some balance in the rapid shutdown requirements that are in the NEC? 


---

On 2020-04-29 07:27, Sky Sims wrote: 

So far rapid shutdown has been a nightmare. It's added a lot of cost for no measurable benefit. 
Using always off devices like midnight solar and Tigo makes it impossible to test open circuit voltages. Which opens the door to tons of problems when commissioning systems.  
Also we've been trying out midnight Solar's product and have had an absurd failure rate. Which means lots of truck rolls and troubleshooting and system downtime. They send replacement product but they aren't paying for the lost weeks of productivity. 
We have Tigo product in hand and are deciding which project to try it on. But our big concern about using it is not only the inabi

Re: [RE-wrenches] Rapid Shutdown Compliance

[Jason Szumlanski]

"Rapid Shutdown does not prevent fires."

Not true. If the effect of RS is to steer the market to MLPE, I believe it
has a significant impact on reducing fire risk. As one who has watched a DC
conductor fire smolder out of control, I am sold on an AC module or
microinverter architecture. While RS on a DC array doesn't necessarily
reduce fire risk within the array, it still has the potential to reduce
severity and spread. Nothing is going to prevent all fires. I get that.
We're talking about risk mitigation when it comes to RS.

As for "dependable string inverters," the one dependable feature is failure
at least once in the module lifetime, accompanied by a shocking repair bill.

I'm not a shiny object following kind of guy, but the writing is on the
wall. MLPE is the future. Modular, serviceable, disposable if you will.
Like it or not, Edison is going to lose this battle to Tesla (Tom vs
Nikola). And I live less than 5 minutes away from Tommy E's winter home in
Fort Myers, FL. And I "grew up" in the industry living off-grid in DC
power. But AC distribution wins for safety at various scales.






On Wed, Apr 29, 2020, 9:42 PM  wrote:

> Rapid Shutdown does not prevent fires; it was originally drafted to allow
> firefighters to vent a roof without being hindered by energized PV arrays.
> This rule was expanded to include other DC wiring from PV sources.
>
> As for PV safety, I’d like to see some significant, statistical evidence
> that shows there is a major fire danger from PV relative to other sources.
> A fire from a solar array gets a lot more press than one from a gas leak,
> bad wiring or an ash tray emptied into a wastepaper basket.
>
> Large public buildings should have all the protection that is available.
> Does one size fit all?
>
> Would it be reasonable to allow residential installations under 12 kW,
> with 1/4 of the roof adjacent to the array available for venting, to be
> excepted from 690.12? What about sparsely occupied commercial buildings
> with ample roof area open for ventilation?
>
> Many of us have chosen to work with renewable energy technology to lessen
> the harms caused by fossil fuel extraction and combustion. The need for
> non-carbon based energy sources has become extremely clear.
>
> The old string inverters still chug along year after year, with little or
> no maintenance. Someone must pay for the ongoing maintenance of module
> level electronics. Dependable string inverter systems should be allowed
> unless statically significant danger can be demonstrated.
>
> Drake
> ---
>
>
>
> On 2020-04-29 16:01, Jason Szumlanski wrote:
>
> I have been to several PV fires for string inverter systems, both
> commercial and residential, and have seen many DC systems at serious risk
> of fires or in various stages of melted insulation and connectors. Most of
> these systems have exhibited good to excellent workmanship. Things just
> went wrong. Some were traceable to animal damage, wind, or other
> unmitigated factors, and some were unexplained. I disagree that there isn't
> justification for rapid shutdown.
>
> In my opinion, what we need is some additional innovation and competition
> in the MLPE space. Reliability is clearly a key factor, but there is no
> denying that MLPE has added safety benefits among other benefits. And if
> you do enough volume and set up your business for efficiency
> (standardization of product offerings), MLPE isn't much more expensive. It
> becomes a negligible cost relative to the benefit. The value proposition is
> easy to convey. There are limits to this, but for the majority of
> residential and small commercial installations, MLPE has become the de
> facto standard around here. String inverters are dinos, and replacing 8-12
> year old transformer based inverters is many times more annoying than some
> MLPE swaps. I will admit that the roofs around here are pretty easy to
> walk, so that is a factor that might not apply to you.
>
> If you go under due to manufacturer product failures, you are not writing
> your contracts right or not charging enough for service issues beyond your
> control. I believe that's a red herring. You might suffer some reputation
> damage, but for someone that has been installing MLPE for over a decade,
> that is totally manageable. Consumers find a service call to replace MLPE a
> LOT more palatable than a surprise inverter replacement that could cost
> thousands of dollars. People just don't plan for that.
>
> Regarding rapid shutdown devices, I have also come across a few that
> "someone" has bypassed around here. I don't know if they were never
> installed properly or disabled/bypassed due to failure. It seemed
> suspicious to me at the time. I remember that it made me wonder what good
> is a rapid shutdown device if it is easily defeated? That's another
> argument for MLPE. It has pretty failsafe MLPE functionality.
>
> Jason Szumlanski
> Florida Solar Design Group
>
>
>
> On Wed, Apr 29, 2020 at 10:59 AM 
> wrote:
>
> Clear

Re: [RE-wrenches] Rapid Shutdown Compliance

[Jason Szumlanski]

I have been to several PV fires for string inverter systems, both
commercial and residential, and have seen many DC systems at serious risk
of fires or in various stages of melted insulation and connectors. Most of
these systems have exhibited good to excellent workmanship. Things just
went wrong. Some were traceable to animal damage, wind, or other
unmitigated factors, and some were unexplained. I disagree that there isn't
justification for rapid shutdown.

In my opinion, what we need is some additional innovation and competition
in the MLPE space. Reliability is clearly a key factor, but there is no
denying that MLPE has added safety benefits among other benefits. And if
you do enough volume and set up your business for efficiency
(standardization of product offerings), MLPE isn't much more expensive. It
becomes a negligible cost relative to the benefit. The value proposition is
easy to convey. There are limits to this, but for the majority of
residential and small commercial installations, MLPE has become the de
facto standard around here. String inverters are dinos, and replacing 8-12
year old transformer based inverters is many times more annoying than some
MLPE swaps. I will admit that the roofs around here are pretty easy to
walk, so that is a factor that might not apply to you.

If you go under due to manufacturer product failures, you are not writing
your contracts right or not charging enough for service issues beyond your
control. I believe that's a red herring. You might suffer some reputation
damage, but for someone that has been installing MLPE for over a decade,
that is totally manageable. Consumers find a service call to replace MLPE a
LOT more palatable than a surprise inverter replacement that could cost
thousands of dollars. People just don't plan for that.

Regarding rapid shutdown devices, I have also come across a few that
"someone" has bypassed around here. I don't know if they were never
installed properly or disabled/bypassed due to failure. It seemed
suspicious to me at the time. I remember that it made me wonder what good
is a rapid shutdown device if it is easily defeated? That's another
argument for MLPE. It has pretty failsafe MLPE functionality.

Jason Szumlanski
Florida Solar Design Group



On Wed, Apr 29, 2020 at 10:59 AM 
wrote:

> Clearly, rapid shutdown increases cost and reduces reliability. Given the
> excellent safety record of PV, prior to rapid shutdown being required, it
> is unnecessary. The few anecdotal incidents of PV fires were not enough to
> justify the requirement, especially on smaller systems.
>
> According to a friend who worked for a local installation company that
> went under, a big part of the reason for their failure was the chronic
> replacement of microinverters and optimizers.
>
> What steps can be taken to create some balance in the rapid shutdown
> requirements that are in the NEC?
>
>
> ---
>
>
>
> On 2020-04-29 07:27, Sky Sims wrote:
>
> So far rapid shutdown has been a nightmare. It's added a lot of cost for
> no measurable benefit.
> Using always off devices like midnight solar and Tigo makes it impossible
> to test open circuit voltages. Which opens the door to tons of problems
> when commissioning systems.
> Also we've been trying out midnight Solar's product and have had an absurd
> failure rate. Which means lots of truck rolls and troubleshooting and
> system downtime. They send replacement product but they aren't paying for
> the lost weeks of productivity.
> We have Tigo product in hand and are deciding which project to try it on.
> But our big concern about using it is not only the inability to confirm
> open circuit voltage of the strings but also the way panels bypass if the
> device doesn't allow the panel to connect properly. Both of these features
> are a recipe for problems and potential troubleshooting nightmares. The
> warranty from Tigo doesn't cover our expense if the product fails. And
> that's really what our reservations about the product boil down to right
> now. If we're on a job with 50 units and one fails, the contractor or the
> homeowner will be the ones eating the expense of finding it and replacing
> it. There has to be a better option.
>
> Sky Sims
> Https://EcologicalSystems.biz
>
> On Apr 28, 2020, at 7:46 PM, Corey Shalanski  wrote:
>
> Now that 690.12 of the *NEC* 2017 has been in effect for several years, I
> am curious how designers and installers are meeting the associated
> requirements with string inverter-based systems (*not* considering
> microinverters or DC optimizers). I am generally a fan of the KISS
> principle, and as best I can determine the *Tigo* TS4-F device is one of
> the simplest options currently available on the market. What are others
> finding?
>
> I'd love to hear about favored options for complying with rapid shutdown.
> Any success stories? or better yet, any early failures?
>
> --
> Corey Shalanski
> Jah Light Solar
> Portland, Jamaica
> __

Re: [RE-wrenches] Rapid Shutdown Compliance

[Darryl Thayer]

my two cents worth, 690.11 says turn off from all arcs, that means serial
and parallel
that means module lwevel shutdown
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Re: [RE-wrenches] Rapid Shutdown Compliance

[Ray]

I agree, 690.12 should have exemptions for lower voltage, lower power 
systems, and shorter runs; especially off grid.  10 years ago, I was 
promoting some type of remote controlled disconnect at the array, but 
that was for voltages over 400v, with unprotected conduit runs over a 
100 ft long, on systems over 10 kW.


For off grid where reliability is the number one safety issue, we've 
gone back to pole mounts to avoid 690.12.  If the temperature goes below 
zero, and the customer is snow bound, having the Rapid disconnect trip 
off is NOT creating a safer situation.  They need heat, unfrozen water 
supply, and communications.    Rural VFDs are not going to usually even 
get up on the roof anyway.  That's a scenario for in town, when they can 
respond in less than 10 minutes.


Actually for residential systems in rural areas, the only person that is 
going to get hurt on the roof is the customer trying to reset the Rapid 
Disconnect, not the Fire Department.  Maybe the NEC task groups will 
finally see that fire fighter safety needs to be balanced with the 
safety of the people they are trying to protect. I hope that the NEC 
could reach this conclusion before an untrained home owner breaks their 
neck.


Ray Walters
Remote Solar
303 505-8760

On 4/29/20 10:17 AM, drake.chamber...@redwoodalliance.org wrote:


Clearly, rapid shutdown increases cost and reduces reliability. Given 
the excellent safety record of PV, prior to rapid shutdown being 
required, it is unnecessary. The few anecdotal incidents of PV fires 
were not enough to justify the requirement, especially on smaller 
systems.


According to a friend who worked for a local installation company that 
went under, a big part of the reason for their failure was the chronic 
replacement of microinverters and optimizers.


What steps can be taken to create some balance in the rapid shutdown 
requirements that are in the NEC?



---


On 2020-04-29 07:27, Sky Sims wrote:

So far rapid shutdown has been a nightmare. It's added a lot of cost 
for no measurable benefit.
Using always off devices like midnight solar and Tigo makes it 
impossible to test open circuit voltages. Which opens the door to 
tons of problems when commissioning systems.
Also we've been trying out midnight Solar's product and have had an 
absurd failure rate. Which means lots of truck rolls and 
troubleshooting and system downtime. They send replacement product 
but they aren't paying for the lost weeks of productivity.
We have Tigo product in hand and are deciding which project to try it 
on. But our big concern about using it is not only the inability to 
confirm open circuit voltage of the strings but also the way panels 
bypass if the device doesn't allow the panel to connect properly. 
Both of these features are a recipe for problems and potential 
troubleshooting nightmares. The warranty from Tigo doesn't cover our 
expense if the product fails. And that's really what our reservations 
about the product boil down to right now. If we're on a job with 50 
units and one fails, the contractor or the homeowner will be the ones 
eating the expense of finding it and replacing it. There has to be a 
better option.


Sky Sims
Https://EcologicalSystems.biz

On Apr 28, 2020, at 7:46 PM, Corey Shalanski  
wrote:


Now that 690.12 of the /NEC/ 2017 has been in effect for several 
years, I am curious how designers and installers are meeting the 
associated requirements with string inverter-based systems (*not* 
considering microinverters or DC optimizers). I am generally a fan 
of the KISS principle, and as best I can determine the /Tigo/ TS4-F 
device is one of the simplest options currently available on the 
market. What are others finding?
I'd love to hear about favored options for complying with rapid 
shutdown. Any success stories? or better yet, any early failures?

--
Corey Shalanski
Jah Light Solar
Portland, Jamaica
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_

[RE-wrenches] Used FM 80

[drake . chamberlin]

How much would you pay for an FM 80 manufactured in 03/2012? It works. 
It came out of a system with 4 controllers, one failed? I want to use it 
for a temporary, while failed controllers are in the shop or having 
replacements shipped.


--
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Re: [RE-wrenches] Rapid Shutdown Compliance

[Dave Angelini Offgrid Solar]

My 2 cents are related to the very few times I have had to do RS for
offgrid. My advice is to install whatever the inspector wants, assuming he
can't be convinced of the mindless requirement. Complete the installation.
Do the right thing after by abandoning it. Have the client remove the RS
signing so fire folks do not get misled. 

I am testing the Schneider RS
here on one array, but XW is out of the loop. Just logging. 

Dave Angelini
Offgrid Solar
"we go where powerlines
don't"
http://members.sti.net/offgridsolar/ [1]
e-mail offgridso...@sti.net
[2]
text 209 813 0060

On Wed, 29 Apr 2020 10:17:33 -0400,
drake.chamber...@redwoodalliance.org wrote:  

Clearly, rapid shutdown
increases cost and reduces reliability. Given the excellent safety record
of PV, prior to rapid shutdown being required, it is unnecessary. The few
anecdotal incidents of PV fires were not enough to justify the requirement,
especially on smaller systems. 

According to a friend who worked for a
local installation company that went under, a big part of the reason for
their failure was the chronic replacement of microinverters and optimizers.


What steps can be taken to create some balance in the rapid shutdown
requirements that are in the NEC? 

  ---

On 2020-04-29 07:27, Sky Sims
wrote:   So far rapid shutdown has been a nightmare. It's added a lot of
cost for no measurable benefit. Using always off devices like midnight
solar and Tigo makes it impossible to test open circuit voltages. Which
opens the door to tons of problems when commissioning systems.  Also we've
been trying out midnight Solar's product and have had an absurd failure
rate. Which means lots of truck rolls and troubleshooting and system
downtime. They send replacement product but they aren't paying for the lost
weeks of productivity. We have Tigo product in hand and are deciding which
project to try it on. But our big concern about using it is not only the
inability to confirm open circuit voltage of the strings but also the way
panels bypass if the device doesn't allow the panel to connect properly.
Both of these features are a recipe for problems and potential
troubleshooting nightmares. The warranty from Tigo doesn't cover our
expense if the product fails. And that's really what our reservations about
the product boil down to right now. If we're on a job with 50 units and one
fails, the contractor or the homeowner will be the ones eating the expense
of finding it and replacing it. There has to be a better option.  
 Sky
Sims Https://EcologicalSystems.biz  
 On Apr 28, 2020, at 7:46 PM, Corey
Shalanski  wrote:

Now that 690.12 of the _NEC_ 2017 has been in effect
for several years, I am curious how designers and installers are meeting
the associated requirements with string inverter-based systems (*not*
considering microinverters or DC optimizers). I am generally a fan of the
KISS principle, and as best I can determine the _Tigo_ TS4-F device is one
of the simplest options currently available on the market. What are others
finding?   I'd love to hear about favored options for complying with rapid
shutdown. Any success stories? or better yet, any early failures?   --
Corey Shalanski Jah Light Solar Portland, Jamaica 
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Re: [RE-wrenches] Rapid Shutdown Compliance

[Jay]

Hi Drake 

I will disagree, there have been many roof top fires. 

But regardless we have to do these new regulations and I for one welcome the 
safety. 

The main issue is accessing the faulty/suspect component under the module 
possibly requiring removing multiple modules, a slow and expensive process. 

My technique is to install the MLPE at the edges of the array, using wire 
extensions. That way at most I have to remove a single module.  And Im working 
on a drop bracket which would allow better cooling and easier access without 
module removal to the MLPE, greatly reducing time to swap. 

Jay

Peltz Power. 





> On Apr 29, 2020, at 7:59 AM, drake.chamber...@redwoodalliance.org wrote:
> 
> 
> Clearly, rapid shutdown increases cost and reduces reliability. Given the 
> excellent safety record of PV, prior to rapid shutdown being required, it is 
> unnecessary. The few anecdotal incidents of PV fires were not enough to 
> justify the requirement, especially on smaller systems.
> 
> According to a friend who worked for a local installation company that went 
> under, a big part of the reason for their failure was the chronic replacement 
> of microinverters and optimizers.
> 
> What steps can be taken to create some balance in the rapid shutdown 
> requirements that are in the NEC?
> 
> 
> 
> ---
>  
> 
> 
>> On 2020-04-29 07:27, Sky Sims wrote:
>> 
>> So far rapid shutdown has been a nightmare. It's added a lot of cost for no 
>> measurable benefit.
>> Using always off devices like midnight solar and Tigo makes it impossible to 
>> test open circuit voltages. Which opens the door to tons of problems when 
>> commissioning systems. 
>> Also we've been trying out midnight Solar's product and have had an absurd 
>> failure rate. Which means lots of truck rolls and troubleshooting and system 
>> downtime. They send replacement product but they aren't paying for the lost 
>> weeks of productivity.
>> We have Tigo product in hand and are deciding which project to try it on. 
>> But our big concern about using it is not only the inability to confirm open 
>> circuit voltage of the strings but also the way panels bypass if the device 
>> doesn't allow the panel to connect properly. Both of these features are a 
>> recipe for problems and potential troubleshooting nightmares. The warranty 
>> from Tigo doesn't cover our expense if the product fails. And that's really 
>> what our reservations about the product boil down to right now. If we're on 
>> a job with 50 units and one fails, the contractor or the homeowner will be 
>> the ones eating the expense of finding it and replacing it. There has to be 
>> a better option. 
>> 
>> Sky Sims
>> Https://EcologicalSystems.biz
>> 
>>> On Apr 28, 2020, at 7:46 PM, Corey Shalanski  wrote:
>>> 
>>> Now that 690.12 of the NEC 2017 has been in effect for several years, I am 
>>> curious how designers and installers are meeting the associated 
>>> requirements with string inverter-based systems (*not* considering 
>>> microinverters or DC optimizers). I am generally a fan of the KISS 
>>> principle, and as best I can determine the Tigo TS4-F device is one of the 
>>> simplest options currently available on the market. What are others finding?
>>>  
>>> I'd love to hear about favored options for complying with rapid shutdown. 
>>> Any success stories? or better yet, any early failures?
>>>  
>>> --
>>> Corey Shalanski
>>> Jah Light Solar
>>> Portland, Jamaica
>>> ___
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Re: [RE-wrenches] Rapid Shutdown Compliance

[drake . chamberlin]

Clearly, rapid shutdown increases cost and reduces reliability. Given
the excellent safety record of PV, prior to rapid shutdown being
required, it is unnecessary. The few anecdotal incidents of PV fires
were not enough to justify the requirement, especially on smaller
systems. 


According to a friend who worked for a local installation company that
went under, a big part of the reason for their failure was the chronic
replacement of microinverters and optimizers. 


What steps can be taken to create some balance in the rapid shutdown
requirements that are in the NEC? 


---

On 2020-04-29 07:27, Sky Sims wrote:

So far rapid shutdown has been a nightmare. It's added a lot of cost for no measurable benefit. 
Using always off devices like midnight solar and Tigo makes it impossible to test open circuit voltages. Which opens the door to tons of problems when commissioning systems.  
Also we've been trying out midnight Solar's product and have had an absurd failure rate. Which means lots of truck rolls and troubleshooting and system downtime. They send replacement product but they aren't paying for the lost weeks of productivity. 
We have Tigo product in hand and are deciding which project to try it on. But our big concern about using it is not only the inability to confirm open circuit voltage of the strings but also the way panels bypass if the device doesn't allow the panel to connect properly. Both of these features are a recipe for problems and potential troubleshooting nightmares. The warranty from Tigo doesn't cover our expense if the product fails. And that's really what our reservations about the product boil down to right now. If we're on a job with 50 units and one fails, the contractor or the homeowner will be the ones eating the expense of finding it and replacing it. There has to be a better option.  

Sky Sims 
Https://EcologicalSystems.biz 


On Apr 28, 2020, at 7:46 PM, Corey Shalanski  wrote:


Now that 690.12 of the _NEC_ 2017 has been in effect for several years, I am curious how designers and installers are meeting the associated requirements with string inverter-based systems (*not* considering microinverters or DC optimizers). I am generally a fan of the KISS principle, and as best I can determine the _Tigo_ TS4-F device is one of the simplest options currently available on the market. What are others finding? 

I'd love to hear about favored options for complying with rapid shutdown. Any success stories? or better yet, any early failures? 


--
Corey Shalanski 
Jah Light Solar 
Portland, Jamaica ___

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Re: [RE-wrenches] Rapid Shutdown Compliance

[August Goers]

Hi Corey - As we've grown, and as our fleet of installed systems has grown,
I've become increasingly interested in choosing an inverter solution that
shows per-module production data. I realize that you specifically asked not
to consider optimizers or microinverters, but I wonder if that will be a
losing battle. Module Level Power Electronics (MLPE) are getting more and
more reliable, and allow us to see what is actually happening with the
system for relatively easy troubleshooting down the road. Simply put, the
benefits outweigh the drawbacks, and they are only getting better.

That said, we're seeing some integrators going with the SMA / Tigo route
where you can choose the TS4-F rapid-shutdown-only variant of the Tigo unit
to reduce cost. You mentioned this. From the cost analysis that I've run,
I'm finding the SolarEdge is actually a bit cheaper than the SMA / Tigo
TS4-F route, especially when factoring in the long and flexible string
designs possible with SolarEdge. It's certainly possible that the KISS
route will pay off if one selects the Tigo route, but I think it's really
anyone's guess about which MLPE device will last the longest. Then there
are AC modules and Enphase type microinverters which are even simpler to
design and install with.

Anyway, it's a good question about whether there are any other viable
solutions to meet NEC 2017 rapid shutdown requirements out there. But I'm
afraid that the days of simple DC string based inverter systems are gone.

August
Luminalt




On Tue, Apr 28, 2020 at 4:46 PM Corey Shalanski  wrote:

> Now that 690.12 of the *NEC* 2017 has been in effect for several years, I
> am curious how designers and installers are meeting the associated
> requirements with string inverter-based systems (*not* considering
> microinverters or DC optimizers). I am generally a fan of the KISS
> principle, and as best I can determine the *Tigo* TS4-F device is one of
> the simplest options currently available on the market. What are others
> finding?
>
> I'd love to hear about favored options for complying with rapid shutdown.
> Any success stories? or better yet, any early failures?
>
> --
> Corey Shalanski
> Jah Light Solar
> Portland, Jamaica
> ___
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Re: [RE-wrenches] Rapid Shutdown Compliance

[Sky Sims]

So far rapid shutdown has been a nightmare. It’s added a lot of cost for no 
measurable benefit.
Using always off devices like midnight solar and Tigo makes it impossible to 
test open circuit voltages. Which opens the door to tons of problems when 
commissioning systems. 
Also we’ve been trying out midnight Solar’s product and have had an absurd 
failure rate. Which means lots of truck rolls and troubleshooting and system 
downtime. They send replacement product but they aren’t paying for the lost 
weeks of productivity.
We have Tigo product in hand and are deciding which project to try it on. But 
our big concern about using it is not only the inability to confirm open 
circuit voltage of the strings but also the way panels bypass if the device 
doesn’t allow the panel to connect properly. Both of these features are a 
recipe for problems and potential troubleshooting nightmares. The warranty from 
Tigo doesn’t cover our expense if the product fails. And that’s really what our 
reservations about the product boil down to right now. If we’re on a job with 
50 units and one fails, the contractor or the homeowner will be the ones eating 
the expense of finding it and replacing it. There has to be a better option. 

Sky Sims
Https://EcologicalSystems.biz

> On Apr 28, 2020, at 7:46 PM, Corey Shalanski  wrote:
> 
> 
> Now that 690.12 of the NEC 2017 has been in effect for several years, I am 
> curious how designers and installers are meeting the associated requirements 
> with string inverter-based systems (*not* considering microinverters or DC 
> optimizers). I am generally a fan of the KISS principle, and as best I can 
> determine the Tigo TS4-F device is one of the simplest options currently 
> available on the market. What are others finding?
> 
> I'd love to hear about favored options for complying with rapid shutdown. Any 
> success stories? or better yet, any early failures?
> 
> --
> Corey Shalanski
> Jah Light Solar
> Portland, Jamaica
> ___
> List sponsored by Redwood Alliance
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