Solar Rapid Shutdown: Everything You Need to Know

Solar rapid shutdown is a way to prevent your solar array from generating electricity in case of fire or other emergencies. This allows firefighters to climb on the roof to curb the damage without the risk of getting electrocuted. Installing a rapid shutdown switch on your solar panel is important to reduce the voltage when needed.

Solar panels with rapid shutdown capabilities can get expensive, but if your budget is less, opt for reliable and safe Jackery Solar Generators. Aside from being affordable, the Jackery Portable Power Stations feature a high-quality built-in MPPT charge controller and a pure sine wave inverter to protect the power station against short circuits, overcharge, and overvoltages, ensuring safe power supply to most household appliances during power outages.

Key Takeaways

• Solar rapid shutdown came into existence in 2014 to quickly reduce the voltage flow in conductors during a fire.
• Your solar panel must have a rapid shutdown switch to abide by the mandate and ensure the safety of first responders during an emergency.
• The regulation codes vary from one state to another, depending on the NEC they’ve adopted.
• Microinverters, power optimizers, and string inverters are two types of solar installations.
• NEC 2014, 2017, and 2020 are the legal requirements for solar rapid shutdown installations.

What Is Solar Rapid Shutdown?

Solar rapid shutdown is a safety mandate set by the National Electrical Code (NEC) to shut down or de-energize a solar panel system during emergencies. Introduced in 2014 as a safety precaution, its primary purpose is to provide firefighters with a way to quickly shut down the power source during a fire.

The NFPA, or National Fire Protection Association, wrote the rapid shutdown requirements for the NEC to keep the first responders safe. Surprisingly, just turning off the inverter during a fire doesn’t work, as in some setups, circuits, and wires remain energized even if the inverter is turned off, putting the firefighters working on the roof at risk of shock. So, the mandate requires the inverters to include a disconnect switch that reduces the voltage level of your solar system within the safety levels in less than a minute.

Why Is Solar Rapid Shutdown So Important?

Solar panel systems charge when the sun comes on top, and live electricity starts flowing through the attached conductors. And there’s no way to turn off the current flow without a rapid shutdown system.

In most situations, it’s safe as current flows from panels to inverters through conduits, but sometimes it can get unpredictable. It especially happens during a fire or other emergencies when the conduits get damaged and expose the person nearby to live electricity. The firefighters and other first responders are at a huge risk trying to curb the overall damage.

It is where the rapid shutdown of solar panels is essential. The first responders can quickly flip a switch to cut off the power in conduits and stay safe working around them.    

Do I Need to Add Solar Rapid Shutdown to My System?

Yes, it’s required by law to add a solar rapid shutdown system to your solar panel system. Importantly, NEC isn’t a federal law, so individual states have the option to adopt and comply with the code; hence, the solar rapid shutdown requirements might vary from one state to another.   Even if there isn’t any mandate, it’s important to install one to ensure the safety of first responders during emergencies or anyone who needs to access the roof.  

Most states in the United States have set shutdown requirements; however, it varies with the code in effect. Every three years, NEC releases safety electrical system requirements, and each state adopts them as per their time and discretion. For example, Alabama and Oklahoma abide by the NEC 2014 requirements, while New York, Nebraska, and New Jersey by the NEC 2017 requirements. So, it’s important to check the established requirements in your area and design your solar arrays accordingly.

How Can I Get Solar Rapid Shutdown for My System?

If you are seeking to install rapid shutdown for your solar arrays, there’s a high chance that the equipment you purchase already includes a rapid shutdown functionality. These are the two types of solar rapid shutdown installations:  

With Microinverters and Power Optimizers

Microinverters are small inverters installed on an individual solar panel and convert the DC power each generates into usable AC power. At the same time, power optimizers perform Maximum Power Point Tracking (MPPT) on each solar panel to maximize its power output but don’t convert DC into AC current. Although both differ in functionality, they are designed with rapid shutdown capabilities to keep the current voltage level flowing through each solar panel within safety limits so it doesn’t affect the entire system and bolsters its overall reliability and performance.

This way, microinverters and power optimizers also help comply with the NEC’s rapid shutdown requirements for solar installations.

With String Inverters

String inverters, as opposed to a single installation with microinverters and power optimizers, are connected to a string of solar panels, known as the solar array. These convert the entire DC current collected by the solar panels into AC current at a centralized location. So, rather than an individual solar panel, flipping the rapid shutdown switch reduces the voltage level of the entire string in no time.

These are typically less expensive than microinverters and power optimizers, and their centralized operationality simplifies design and maintenance. But it might shut down the panels that aren’t exposed to any damage, further impacting its overall reliability and effectiveness.   

Do All Inverters Have Rapid Shutdown Capabilities?

Some inverters currently on offer have built-in rapid shutdown capabilities, while others need other components to facilitate the functionality. The most popular inverter systems in US are micro-inverters and power optimizers that operate at a panel site and have built-in capabilities, while, as mentioned above, string inverters also boast the functionality. But other than that, inverters don’t have rapid shutdown capabilities, and the reasons are as follows:

Technological Complexity: Integrating the rapid shutdown feature in an inverter at a module level, as in microinverters and power optimizers, requires additional software and hardware, which complicates the overall design and manufacturing process. The same is the case with string inverters with the inclusion of complex internal mechanisms to de-energize an entire string at a time.

Besides, the new technologies and mechanisms might not be compatible with the existing inverters without rapid shutdown capabilities.

Regulatory Variability: Rapid shutdown mechanisms are typically driven by safety regulations set by NEC in the United States, which evolve over time. And retrofitting the inverters with changing regulations can be complex and costly.

Cost Considerations: Adding rapid shutdown functionalities into existing inverters requires integrating additional components like module-level power electronics. It further adds up to the overall cost of the inverter. ‘

Inverter Lifespan: A typical inverter lasts up to 15 years, and the systems introduced before the NEC 2014 enactment are still in operation and might not be upgraded until all of them need replacement.        

What Are The Legal Requirements for Solar Rapid Shutdown Installations?

Currently, three NEC requirement codes are in place, which are explained as follows:

NEC 2014

When the first regulations were written in 2014, the requirements included reducing the voltage of conductors more than 10 feet outside the system or 5 feet inside a building quickly during emergencies, hence the rapid shutdown switch. Eight states have adopted this edition, including Delaware, Alabama, Louisiana, Montana, Maryland, Oklahoma, Pennsylvania, and Virginia.

NEC 2017

In 2017, the regulations were revised and expanded the shutdown to an individual solar module rather than an entire array. This means, using a rapid shutdown switch, any conductor beyond 1 foot of the system must get the voltage down to safe limits within half a minute, as opposed to 10 feet in 2014. Around 26 states adopted the following edition, and Alaska, Arkansas, Connecticut, Hawaii, North Carolina, New York, Nebraska, and New Jersey are to name a few.

NEC 2020

The latest edition of NEC saw no major changes except the guidelines related to the array boundary. They now require a field-labeled or UL-listed PV Hazard Control System (PVHCS) rather than a rapid shutdown system. The states that adopted the code are Massachusetts, Georgia, Colorado, North Dakota, South Dakota, Minnesota, Washington, Texas, and Wyoming.  

What If The Older Or Ground-Mounted Solar Systems?

If your solar system installation dates back to before NEC 2014 was implemented, then you won’t need to retrofit a rapid shutdown switch into your system. But if you plan to make substantial changes or upgrade it in the future, which requires inspection, you must install components to integrate such into the system. Other than that, as per NEC, you won’t need any rapid shutdown switch if you have a ground-mounted solar system.

As mentioned, safety is the primary criterion of such installations, but often, these turn out to be costly affairs. So, if you want to invest in clean and renewable energy that’s safe from potential accidents and affordable, then invest in Jackery Portable Power Stations.

These feature an MPPT charge controller, similar to those found in power optimizers, that ensures enhanced security during the charging process. They are also known to improve the performance and efficiency of solar generators and can generate up to 30% more than traditional PWM controllers. Importantly, it monitors the solar panel, determines the maximum power point voltage for the current conditions, and converts it for battery charging at appropriate levels. In this way, excess voltage passing through solar panels doesn’t impact the performance or potentially damage the battery.

Besides that, each power station builts in a pure sine wave inverter that ensures your machines operate at safe power levels, thereby improving their efficiency and extending their life.

Jackery Solar Generators Explained

Jackery is a leading manufacturer of solar generators, solar panels, and portable power stations. Each Jackery Explorer Portable Power Station features an MPPT controller for efficient solar charging. Besides, a pure sine wave inverter offers safe operation to power up most of your equipment, including microwave, refrigerator, CPAP machine, and others. The power source is efficient and reliable enough for your demands, whether you’re planning off-grid living, camping trips, or home backup power supplies.  

To utilize solar energy, Jackery Solar Generators combines its power stations with foldable and lightweight Jackery SolarSaga Solar Panels that convert the sun’s rays into DC current in only a minute. The pure sine wave inverter further converts DC into AC current in about a minute and maintains a continuous power supply.

Jackery Solar Generator 3000 Pro

The Jackery Solar Generator 3000 Pro, with its large battery capacity, can power a range of appliances for an extended duration. Using a pure sine wave inverter and MPPT technology, it achieves up to 99% charging efficiency, ensures optimal voltage flow, and does not damage the appliances under any circumstances. You can charge it with a car battery and wall outlets in no time.

Here’s the list of appliances and their running hours with the solar generator:

• Refrigerator (520W): 5H
• TV (60W): 42H
• Light (5W): 514H
• Microwave (700W): 3.6H
• Portable Air Conditioner (1150W): 2.2H