Many states in the US now actually ask for solar energy systems to have devices installed that allow for a quick shutdown. It is a safety feature for solar panel systems, introduced in the National Electrical Code (NEC) 2014 and revised in NEC 2020.
This article will provide an overview of solar rapid shutdown requirements, explain the variations between states, and list compliant inverter options. Let’s explore the topic of solar rapid shutdown below.
Contents
- 1 What is Solar Rapid Shutdown and why is it important
- 2 Do inverters have solar rapid shutdown capabilities?
- 3 Does my state have solar rapid shutdown requirements?
- 4 Retrofitting Existing Solar Panel Systems
- 5 Identifying Whether Your Solar Panel System Requires Retrofitting
- 6 Tips to help you find Suitable Professionals
- 7 FAQs
- 8 Conclusion
What is Solar Rapid Shutdown and why is it important
Have you heard people mention the addition of rapid shutdown functionality to their rooftop solar panel system, or seen a solar panel system with a box and on/off switch labelled “rapid shutdown”? You may be curious about what this means and why it has become increasingly common in solar panel systems.
Key Features
- Safety: Solar panels continue to generate electricity even when disconnected from grid power. So shutting down a PV system quickly reduce risks.
- Faster response time: firefighters can safely go rooftops without worrying about electrocution hazards.
- Damaged equipment prevention: This item can disconnecting your solar panels,stop further damage to your home.
Protect your home and emergency responders with solar rapid shutdown. Complying with NEC requirements ensures a safer environment.
Do inverters have solar rapid shutdown capabilities?
Answer is yes, some inverter systems do have built-in module-level rapid shutdown functionality, while others require additional components to enable rapid shutdown. In the current market, two common system types are microinverter-based PV systems and string-inverter-based PV systems.
Let’s delve deeper to understand which type of solar rapid shutdown system is the best choice for your needs.
Microinverter-based PV Systems
For residential solar panel systems in the U.S., microinverter and power optimizer systems are highly popular choices due to their built-in rapid shutdown functionality. It is important to take into account these pros and cons and consider your specific needs and circumstances when making a decision.
Pros
Cons
However, fitting a string inverter system with rapid shutdown devices can still be a cost-effective option for homeowner, especially for those who already have string inverter systems. Obviously, it wouldn’t be practical to replace the entire system, so instead installing rapid shutdown devices would be a better choice.
String-inverter-based PV Systems
In contrast to microinverters, string-inverters connect multiple solar panels together in series circuits called strings, which then feed DC power directly into a central string inverter. This single inverter converts the combined DC power into AC for use within your home or to be fed back into the grid. However, it also has pros and cons to be considered, there are:
Pros
Cons
Does my state have solar rapid shutdown requirements?
Most states require rapid shutdown, however,the specific requirements can be different based on the applicable code in effect. NEC 2017 and later codes mandate panel module-level shutdown, which is enforced in 37 states as of July 2020.
However, four states which are Illinois, Arizona, Missouri, and Mississippi do not have statewide NEC in effect, although cities and municipalities may have it.
You can find a current map of the National Electrical Code in each state by visiting the National Fire Protection Association’s website. Below is a summary of the National Electric Code adoption by state:
| CODE | Rapid Shutdown Requirement | States |
| NEC 2020 | Module | CO, GA, IA, MA, ME, MN, ND, OR, SD, TX, WA, WY |
| NEC 2017 | Module | AK, AR, CA, CT, FL, HI, ID, KY, MI, NC, NE, NH, NJ, NM, NV, NY, OH, RI, SC, TN, UT, VA, VT, WI, WV |
Retrofitting Existing Solar Panel Systems
If your solar system was installed before the implementation of NEC safety codes in 2014, there’s no need for retrofitting this feature.
However, if you have recently installed a solar panel system, it is essential to ensure that your rapid shutdown switch is resent and clearly labeled as a “rapid shutdown device” on the PV installation.
Identifying Whether Your Solar Panel System Requires Retrofitting
To determine if your current solar array needs a rapid shutdown upgrade, consider two points:
- The age of your solar panels: If they were installed before 2014 or when NEC requirements came into effect in your state, then you may not be required to retrofit.
- Potential future upgrades: Even if not currently mandated by law, upgrading an older system can improve overall safety.
Tips to help you find Suitable Professionals
When making a decision to install a solar rapid shutdown system, there are some useful tips to help you choose certified professionals with relevant experience:
- Check certifications: Look for certified professionals who have completed training programs by organizations like North American Board of Certified Energy Practitioners (NABCEP) or Solar Energy International (SEI). These certifications guarantee their expertise in installing solar systems compliant with NEC requirements.
- EvRead reviews: Platforms like the EnergySage Marketplace allow you to compare solar installers based on customer feedback.
FAQs
What is the Main Downfall to Solar Power?
The primary drawback of solar power is its intermittent nature due to varying sunlight availability. Solar panels only generate electricity when exposed to sunlight, making them less effective on cloudy days or at night. Additionally, initial installation costs can be high; however, long-term savings often offset these expenses.
What are the NEC Rapid Shutdown Requirements?
The NEC 2017 code mandates that PV systems must rapidly reduce voltage within array boundaries upon activation of their emergency stop function. Within 30 seconds after initiation, conductors outside the array boundary should not exceed 80 volts while those inside should not exceed 30 volts under load conditions (source).
Initiators Alongside Inverters in Designing Compliant Equipment Setups?
In addition to the right type of inverter, other components such as initiators are essential for ensuring compliance with rapid shutdown requirements. Initiators send signals to the inverters and module-level rapid shutdown devices (MLRSDs) during emergencies, triggering the necessary actions for shutting down the solar array safely. To ensure that your setup meets all regulatory standards, consult an experienced solar installer.
What are the additional requirements of the NEC 2020?
The NEC 2020 specifies that RSDs must be listed and labeled for rapid shutdown by follow National Electrical Code (NEC) guidelines
- Ensure all labels comply with specific requirements outlined in the NEC, such as font size and visibility.
- Use durable materials: Labels should be made of weather-resistant materials.
- The rapid shutdown device label should be placed close to the actual switch.
Conclusion
At the end of this post, we now understand that solar rapid shutdown is an important safety thing for any residential solar panel system. In order to use solar panel system safely as well as in compliance with regulations, we should consider the installation of a solar rapid shutdown system.
Research has shown Solar panels will be becoming increasingly popular as a reliable, cost-effective, and clean source of energy, especially as the world moves away from fossil fuels.Homeowners can make informed decisions when upgrading their home’s efficiency score. If you want to know more about solar panel battery storage system, please visit our other post.
