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
We had developed a Rapid Shut Down System a bout 2 years ago. This system consisted of short circuiting PV arrays individually when the Grid AC power to the Inverter was disabled.
The breadboard prototype was ready and passed all the tests. But when we tried to package it in a box, we discovered that, the system produced too much (over 60 Watts) heat and thus called for heat sinking and may even a continuously running fan.
A better version is under development now which is expected to produce no more than 12 Watts of heat (for a system with four PV arrays) and hence would not need any heatsinking.
The breadboard system consisting of many innovations in circuit topologies is expected to be ready by end of August 2022.
Rapid shutdown has become too extreme and for what purpose? It introduces more danger than solves, and seems to be a product of industry infiltrating CMPs within the NEC. I thought that the NEC was apolitical, but they have breached confidentiality and lost my respect.
This is our industries biggest challenge as I see it. The lack of options for MLRSD along with a marginal increase in safety has me questioning the intent of these code changes constantly. Has over complicated design and installation, while driving up cost.
Module-level shutdown is a great way to add costs and failure points. In my experience, it is problematic – at best. It is unclear to me how it significantly increases first responder safety. It is clear to me, however that too few manufacturers are unduly benefiting from the module-level mandate.
We need to swing the pendulum back a bit as fire fighters are aware of the dangers of solar and don’t plan on cutting into arrays because there are still original systems that are not mlsd, so all are treated as typical strings.
More devices and more points of failure cause more issues alone.
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.
Recent Activity
petition signature
Carsten Donohue Moll signed Sign Now
2022-06-23 14:33:59 -0500
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Dan Dean signed Sign Now
2022-06-22 16:29:43 -0500
Module Level shutdown is not necessary. String level we have with fuses and breakers.
If technology advances to accommodate module level, let’s do it. It is way too early yo try this.
Thanks!
Dr. Daniel Dean
Design Engineer
Earth Wise Solar Technologies
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Joseph Thaickal signed Sign Now
2022-06-21 20:08:41 -0500
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Drake Chamberlin signed Sign Now
2022-06-21 13:33:40 -0500
Brent Selby signed Sign Now
2022-06-21 11:46:17 -0500
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Suresh Bhate signed Sign Now
2022-06-21 11:34:32 -0500
We had developed a Rapid Shut Down System a bout 2 years ago. This system consisted of short circuiting PV arrays individually when the Grid AC power to the Inverter was disabled.
The breadboard prototype was ready and passed all the tests. But when we tried to package it in a box, we discovered that, the system produced too much (over 60 Watts) heat and thus called for heat sinking and may even a continuously running fan.
A better version is under development now which is expected to produce no more than 12 Watts of heat (for a system with four PV arrays) and hence would not need any heatsinking.
The breadboard system consisting of many innovations in circuit topologies is expected to be ready by end of August 2022.
petition signature
Christopher Warfel signed Sign Now
2022-06-21 08:42:18 -0500
Rapid shutdown has become too extreme and for what purpose? It introduces more danger than solves, and seems to be a product of industry infiltrating CMPs within the NEC. I thought that the NEC was apolitical, but they have breached confidentiality and lost my respect.
petition signature
Tyler McReynolds signed Sign Now
2022-06-21 04:10:42 -0500
This is our industries biggest challenge as I see it. The lack of options for MLRSD along with a marginal increase in safety has me questioning the intent of these code changes constantly. Has over complicated design and installation, while driving up cost.
petition signature
Alain Mulaire signed Sign Now
2022-06-20 18:15:37 -0500
Module-level shutdown is a great way to add costs and failure points. In my experience, it is problematic – at best. It is unclear to me how it significantly increases first responder safety. It is clear to me, however that too few manufacturers are unduly benefiting from the module-level mandate.
petition signature
Jawad Khattak signed Sign Now
2022-06-20 14:37:02 -0500
petition signature
Mike Maharas signed Sign Now
2022-06-20 14:28:14 -0500
We need to swing the pendulum back a bit as fire fighters are aware of the dangers of solar and don’t plan on cutting into arrays because there are still original systems that are not mlsd, so all are treated as typical strings.
More devices and more points of failure cause more issues alone.
petition signature
John Valentine signed Sign Now
2022-06-20 14:20:01 -0500
petition signature
Dan Johnson signed Sign Now
2022-06-20 13:33:06 -0500
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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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Ben Zook signed Sign Now
2022-06-20 12:23:30 -0500
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James Mikles signed Sign Now
2022-06-20 12:06:01 -0500
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John Hunter signed Sign Now
2022-06-20 12:05:16 -0500
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Antony Tersol signed Sign Now
2022-06-19 23:13:42 -0500
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Don Lossing signed Sign Now
2022-06-18 14:46:35 -0500
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Oliver Lamb signed Sign Now
2022-06-17 17:23:22 -0500
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Srikar Mallavarapu signed Sign Now
2022-06-16 19:23:36 -0500
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Long Nguyen signed Sign Now
2022-06-16 14:30:10 -0500
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Christopher Derby Kilfoyle signed Sign Now
2022-06-16 12:20:14 -0500
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Max Prendergast signed Sign Now
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.
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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:
If technology advances to accommodate module level, let’s do it. It is way too early yo try this.
Thanks!
Dr. Daniel Dean
Design Engineer
Earth Wise Solar Technologies
The breadboard prototype was ready and passed all the tests. But when we tried to package it in a box, we discovered that, the system produced too much (over 60 Watts) heat and thus called for heat sinking and may even a continuously running fan.
A better version is under development now which is expected to produce no more than 12 Watts of heat (for a system with four PV arrays) and hence would not need any heatsinking.
The breadboard system consisting of many innovations in circuit topologies is expected to be ready by end of August 2022.
More devices and more points of failure cause more issues alone.