Solar is the future and green, distributed energy supply is the way to go. PV solar systems are a very safe technology and for many years they've been built without any major safety issues.
However, the adoption of Module Level Shutdown (MLSD) in the National Electrical Code (NEC) has caused some unintended consequences. Because proper MLSD solutions are not available today, systems actually became more complex, less safe, and less reliable.
This puts a tremendous burden on solar installers and system buyers – and at the end, only helps utilities and non-renewable energy suppliers.
Let's fix Module Level Shutdown and do it the right way, so that solar can prosper!
The National Electrical Code requires shutdown devices to be added to virtually every single module. Such additional components at the module level would usually not be necessary for operating a solar system properly. However, solar installers are now forced to using technologies that have major downsides and unintended consequences:
Added Cost and Complexity
Shutdown devices must be added to every single module in a PV system. This increases complexity and cost of systems, as more hardware and more labor is required. On top of that, a duopoly controls 90% of the market for shutdown solutions, limiting customer choice and competition.
Having to add a shutdown device to every single module increases the workers time spent on the roof significantly, which adds to the risks of falling, slipping, or tripping.
Current solutions for Module Level Shutdown (MLSD) compromise the reliability of systems, because a vast number of sensitive electronics is placed in the harsh environment of a roof. Each of these components has a failure rate and wear rate over the 20+ years of a system's lifetime. This can turn into a big liability for solar installers and cause distrust in our industry.
A majority of systems with shutdown solutions based on DC optimizers and microinverters (90% of residential installations) produces less energy than systems without these module level power electronics.
Recent articles in mainstream media, such as CNBC or Business Insider, regarding solar fires with DC connector issues shine a bad light on the solar industry. They make look solar unsafe or not trustworthy. Ignoring this issue would be bad for the industry, becasue solar is generally a very safe technology!
Let’s fix Module Level Shutdown (MLSD) and promote innovative solutions that eliminate these problems and help grow distributed solar as an energy source. Such solutions are chip-based, module integrated, and based an open industry standard (SunSpec) - allowing for simplicity, standardized safety, reliability, and customer choice.
To prevent the unintended consequences of the current code requirements and to allow for systems that are simple, safe, and more reliable, we request that code makers make the following changes to the National Electric Code:
Request 1: Revert NEC 2020 690.12 (Module Level Shutdown) to NEC 2014 690.12 (Array Level Shutdown) requirements until proper solutions are available on the market, such as module-integrated, chip-based devices with an open industry standard
Request 2: Revert to NEC 2014 690.12 but keep the 1' array boundary
Request 3: Implementing a maximum electrical noise level requirement for rapid shutdown devices in 690.12
Request 4: Require 690.11 (Arc Fault Circuit Protection) to apply to all solar PV DC circuits, not just those above 80V, to detect any potential fire safety issues
The module level rapid shutdown rule is totally ridiculous in my opinion. This is increasing the cost of PV all around and has favored companies like Enphase and SolarEdge (two US companies, seems like there might have been a little lobbying going on here?). The module level rapid shutdown does nothing to increase the overall safety of the system. This is touted to protect firefighters, but what about the safety of our installers as there are a lot more roof hours required when installing module level rapid shutdown. No firefighter would ever cut through or touch a solar array in the case of a fire. Please considering changing the code back to the 2014 rapid shutdown requirements so that we can continue advancing the solar industry while also keeping the price accessible for more people.
The challenges and risks are significant. While the complexity with complying with 2017 is noted in the intro section, it seems important to specifically point out the number of additional connection (i.e. failure) points that MLPEs add to a system. A standard string of 16 modules used to have 17 quick connection points. Now it will have almost 3 times the number of connection points — 41 if using 2:1 MLPEs or 49 with 1:1 MLPEs. Further MLPEs introduce the matability connector challenge. In some cases jumpers are needed to address matability, which can increase failure points up to 81 connections where it used to be 17. All of this equipment adds cost (material and labor), which reduces a project’s viability.
Long overdue – Serious Industry wide problem; caused by special industry special interests hyping a fictitious problem (“D.C. is Dangerous”) to capture USA market share.
Europe doesn’t have this problem – they continue to lead with growth of reliable, productive, efficient photovoltaic systems of all sizes & scales.
Time to stop succumbing to special interests driving policy.
Recent Activity
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Mike Poor signed Sign Now
2022-06-20 13:19:54 -0500
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Roland Zeitler signed Sign Now
2022-06-20 12:43:30 -0500
I like the changes you propose, some code- sections are very cumbersome and not helping.
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Kyle Wojewoda signed Sign Now
2022-06-20 12:42:58 -0500
I am an electrical engineer and I support this.
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Mark Hoffman signed Sign Now
2022-06-20 12:26:18 -0500
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2022-06-20 12:23:30 -0500
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2022-06-16 12:20:14 -0500
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2022-06-14 16:49:48 -0500
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Mitch Thompson signed Sign Now
2022-06-14 15:16:45 -0500
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Dennis Robinson signed Sign Now
2022-06-14 14:08:01 -0500
All for movement, agree 100%!
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Tori Zimbardi signed Sign Now
2022-06-13 07:30:21 -0500
The module level rapid shutdown rule is totally ridiculous in my opinion. This is increasing the cost of PV all around and has favored companies like Enphase and SolarEdge (two US companies, seems like there might have been a little lobbying going on here?). The module level rapid shutdown does nothing to increase the overall safety of the system. This is touted to protect firefighters, but what about the safety of our installers as there are a lot more roof hours required when installing module level rapid shutdown. No firefighter would ever cut through or touch a solar array in the case of a fire. Please considering changing the code back to the 2014 rapid shutdown requirements so that we can continue advancing the solar industry while also keeping the price accessible for more people.
petition signature
James D'albora signed Sign Now
2022-06-12 16:14:42 -0500
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Cal Morton signed Sign Now
2022-06-09 12:14:28 -0500
When was the last time anybody saw a ‘first responder’ on a residential roof during a fire?
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Bruce Wood signed Sign Now
2022-06-09 11:33:33 -0500
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Brian Stevens signed Sign Now
2022-04-22 17:33:02 -0500
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Matt Chestosky signed Sign Now
via John Valentine
2022-02-20 18:32:06 -0600
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Josh Gray signed Sign Now
2022-01-20 15:50:55 -0600
The challenges and risks are significant. While the complexity with complying with 2017 is noted in the intro section, it seems important to specifically point out the number of additional connection (i.e. failure) points that MLPEs add to a system. A standard string of 16 modules used to have 17 quick connection points. Now it will have almost 3 times the number of connection points — 41 if using 2:1 MLPEs or 49 with 1:1 MLPEs. Further MLPEs introduce the matability connector challenge. In some cases jumpers are needed to address matability, which can increase failure points up to 81 connections where it used to be 17. All of this equipment adds cost (material and labor), which reduces a project’s viability.
petition signature
Jason Ross signed Sign Now
2022-01-17 10:12:26 -0600
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Donald Zimmerman signed Sign Now
2021-12-30 15:20:20 -0600
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Frank Evaro signed Sign Now
2021-12-30 11:06:12 -0600
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Yolanda Meza signed Sign Now
2021-11-30 18:17:36 -0600
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Brandon Mathis signed Sign Now
2021-09-07 11:53:26 -0500
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Samuel Gartley signed Sign Now
2021-08-11 11:13:43 -0500
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Thomas J. Wineman signed Sign Now
2021-08-07 09:54:19 -0500
Long overdue – Serious Industry wide problem; caused by special industry special interests hyping a fictitious problem (“D.C. is Dangerous”) to capture USA market share.
Europe doesn’t have this problem – they continue to lead with growth of reliable, productive, efficient photovoltaic systems of all sizes & scales.
Time to stop succumbing to special interests driving policy.
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Module Level Shutdown in the National Electric Code has made #solar systems more complex, less safe, and less reliable. Let's #FixMLSD and do it the right way. Sign the petition:
Make Solar Simple, Safe, and More Reliable
Module Level Shutdown in the National Electric Code has made #solar systems more complex, less safe, and less reliable. Let's #FixMLSD and do it the right way. Sign the petition:
Europe doesn’t have this problem – they continue to lead with growth of reliable, productive, efficient photovoltaic systems of all sizes & scales.
Time to stop succumbing to special interests driving policy.