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 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.
I agree to 1 and 2 as temporary measures. 3 and 4 should be replaced with a 3-part standard which is both AFCI and rapid shutdown compliance in one and applies to string inverters, DC DC converters, and combiner box inverter systems as a separate listing, protecting and deenergizing all DC conductors.
More connectors just means more failure points. And without an industry standard for connectors, matching each manufacturer’s connectors can be very difficult. Its as if GE appliances could only be plugged into GE outlets in our houses. Until we have an industry standard for connectors, connector failures will plague our industry.
Just learning about MLSD and it brings back horrible memories of the first round of ArcFault breakers…mandates for unproven technology are a recipe for disaster.
Solar PV Systems are still very new and very competitive business here in the Philippines. The Rapid Shutdown System function requirement adds more costs hence making it less attractive to local customers.
Recent Activity
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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.
petition signature
Bob Mihalcin signed Sign Now
via John Valentine
2021-07-31 07:40:47 -0500
Stop making systems more complex with no real benefit
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Justin Beloy signed Sign Now
2021-07-16 10:06:37 -0500
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Jonathan Topham signed Sign Now
2021-06-10 16:34:40 -0500
I agree to 1 and 2 as temporary measures. 3 and 4 should be replaced with a 3-part standard which is both AFCI and rapid shutdown compliance in one and applies to string inverters, DC DC converters, and combiner box inverter systems as a separate listing, protecting and deenergizing all DC conductors.
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Sergio Montalvo signed Sign Now
2021-06-04 19:20:58 -0500
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Yash Shah signed Sign Now
via jason miller
2021-06-02 12:45:16 -0500
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Montana Busch signed Sign Now
2021-05-30 12:17:20 -0500
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Mark Helmka signed Sign Now
2021-05-28 04:17:26 -0500
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John Mosca signed Sign Now
2021-05-27 20:05:25 -0500
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Jude Pantiliano signed Sign Now
2021-05-27 19:48:47 -0500
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David Wagner signed Sign Now
via Stephen Termotto
2021-05-27 18:14:22 -0500
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Robert Miller signed Sign Now
2021-05-27 15:50:32 -0500
More connectors just means more failure points. And without an industry standard for connectors, matching each manufacturer’s connectors can be very difficult. Its as if GE appliances could only be plugged into GE outlets in our houses. Until we have an industry standard for connectors, connector failures will plague our industry.
petition signature
Pierre Moses signed Sign Now
via Stephen Termotto
2021-05-27 09:18:45 -0500
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Stephen Termotto signed Sign Now
2021-05-27 09:09:04 -0500
Please help us. This code is killing our industry.
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Zach Williams signed Sign Now
via jason miller
2021-05-25 10:09:01 -0500
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Ujval Patel signed Sign Now
via jason miller
2021-05-25 08:50:28 -0500
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jason miller signed Sign Now
2021-05-24 19:36:41 -0500
MLRSD adds thousands more failure points in rooftop systems! Array level 2014 is what code officials should push amd enforce.
petition signature
Daniel Warner signed Sign Now
2021-05-20 13:40:53 -0500
Just learning about MLSD and it brings back horrible memories of the first round of ArcFault breakers…mandates for unproven technology are a recipe for disaster.
petition signature
ev harman signed Sign Now
2021-04-09 22:46:19 -0500
MLPE adds a lot of expense, more complexity, a lot less reliability, and a lot less serviceability, for a negligible increase in fire service safety.
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Nathan Lewis signed Sign Now
via John Valentine
2021-04-06 15:41:26 -0500
Module level shut down adds a day to every install and gives us headache after headache.
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Antonio Tarog signed Sign Now
2021-04-04 23:26:30 -0500
Solar PV Systems are still very new and very competitive business here in the Philippines. The Rapid Shutdown System function requirement adds more costs hence making it less attractive to local customers.
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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.