The National Electrical Code introduced the solar rapid shutdown system in 2014. The main goal was to provide an easier method to de-energize solar energy systems’ direct-current connectors, ensuring safety on the roof if a fire occurs. This is because the DC wiring remains live when you switch off the standard solar system inverter.
If you want to install solar panels, you must have these requirements. In 2017 NEC expanded the rapid shutdown requirements to handle proximity to the system. In this article, we will look at everything you need to know about the rapid solar shutdown. Let’s get started.
What is Solar Rapid Shutdown?
It is a safety requirement that allows de-energizing the system quickly during an emergency. NEC sets critical safety measures to ensure the safety of first respondents in case of a fire. The National Electrical Codes receives updates annually nationwide, ensuring that all solar systems have a way to cut off electricity running through the system.
This requirement only applies to rooftop-mounted solar systems. Users who have ground-mounted solar do not have to meet this requirement.
The Importance of Rapid Solar Rapid Shutdown
Though extremely rare, solar panels can catch fire like any other electrical systems. The same applies to make sources of energy such as gas, nuclear plants, or coal-fired plants. As long as the sun is shining, your solar panel system is generating electricity. This live electricity in the system is okay in normal cases. However, not when there is a fire or any other emergency.
Once fire dames the conduits, it can expose anyone near the system to live electricity, which is dangerous. Installing a rapid shutdown offers safety to first respondents as they can quickly cut off the power.
Rapid Shutdown's Specific Requirements
Your compliance with the NEC regulations will depend on your residential state. Different forms follow either the NEC 2014 or the expanded NEC 2017 regulations.
NEC 2014 Requirements
NEC 2104 states that installers should lower all controlled conductors more than ten feet away from the solar PVs to 30 volts. Also, they go below 240 volt-amperes after initiating the rapid shutdown within ten seconds.
Controlled conductors refer to the conductors capable of transmitting DC or AC power from the PV system as long as they are within ten feet away of the system. Conductors within the system can retain power once a person initiates a shutdown. Additionally, this requirement applies if your solar array is more than five feet in length.
Apart from having a system that can lower its voltage, you should label it properly. You should also label any other solar panels system components. You can choose a switch device or one with on and off button.
Notably, various systems using the string inverter can comply with the NEC 2014 safety requirements without having an extra shutdown switch. When you install the string inverter within ten feet of the solar panels, it eliminates the need for conductors beyond ten feet of the array.
NEC 2017 Requirements
If your state enforces the NEC 2017 rules, you need to meet the expanded requirements. These include:
Any conductors more than one foot of the arrays needs to be de-energized through a rapid shutdown switch. This distance is significantly lower than the NEC 2014 ten-foot zone. Additionally, all solar panels inside this distance should lower to 80 volts within 30 seconds once anyone initiates a shutdown. To comply with this requirement, you can use micro-inverters with capacitors on the front end of the circuitry.
NEC 2017 requirement also indicates that PV arrays without exposed wiring methods and conductive parts installed beyond 8 ft from exposed ground parts should not comply with these requirements.
Frequently Asked Questions
1. Does my old system need to comply with new NEC versions?
If you installed your system before these requirements, you do not need to install the rapid shutdown on the system. However, if you need to expand the system, this is a requirement.
2. What is the purpose of the rapid shutdown push button?
The solar rapid shutdown push-button de-energizes your solar panel system, making it safe for first respondents in case of an emergency.
3. Is rapid shutdown required for ground-mounted solar?
According to NEC, the rapid shutdown is only required for rooftop solar.
4. How do I install rapid shutdown?
Professional solar panel installers will install this system as they install the solar panels depending on the state’s requirements.
