5 Things You Should Know About Rapid Shutdown
Going off-the-power grid has numerous benefits, and this includes financial and environmental advantages. It is one of the most effective methods for lowering your carbon footprint. But before you install your panels on your roof, there are numerous Canadian electric codes (CEC) that your system must meet for it to pass inspections. And one of the most crucial requirements for roof installed solar panels that doesn’t affect the ones installed on the ground is the rapid shutdown feature.
What Is a Rapid Shutdown?
Rapid shutdown is a unique safety requirement for solar systems set by the CEC. This function provides a fast means for de-energizing the solar panels on the roof. The Rapid shutdown function was introduced to our solar energy systems to protect the first responders in case of fire. If your home never catches fire, then you will never have to worry about the role of the Rapid Shutdown switch. But if it does catch fire, then the firefighters can use this switch to de-energize your solar panels before climbing to your roof and doing their job.
Funny enough, simply turning off your inverter doesn’t mean that the entire system is de-energized. With some inverters, the circuit and wires can remain energized even after it’s switched off. And this can increase the risk of the first respondents getting electrocuted while trying to access your house from the roof or working in the attic. And in this scenario, a switch that allows anyone to lower the electric voltage in your system within less than a minute can come in handy.
The rapid shutdown requirement has been operational since 2015 in some parts of Canada. According to the CEC, the Rapid shutdown switch should switch off the PV power at the system’s array, making sure that no live current is running through your building to the system’s inverter. If the fire damages your solar system, it’s always a good idea to have a standalone backup that is not connected to your solar panel system. So make sure you have a fully charged, reliable generator to help power some of the devices in your home after the firefighters have finished their rescue mission.
1. A Rapid Shutdown System Should Be Able to Lower the Voltage to 30v Within Less Than 10 Seconds of Initiation
Normally, firefighters cut a piece of the wall or the roof to help ventilate a burning house and lower the likelihood of smoke getting too thick. Therefore, the right rapid shutdown component should be able to de-energize a solar system within seconds. After all, the solar panel installed on your roof is always live when the sun is shining, which means that the high voltage DC can electrocute anyone who climbs the roof.
According to the CEC requirements, the rapid shutdown system should reduce the high voltage DC in the system to 30v within 10 seconds, making it possible for the firefighters to climb onto the roof and do their job. And the faster the system de-energizes, the higher the likelihood of anyone in the burning house surviving. This will guarantee that no exposed wire can threaten the firefighters while they are keeping us safe.
2. The 2018 CEC Requirements Have Not Been Adopted by All Canadian Provinces
On its own, the Canadian Electric Codes are not part of Canadian laws. They are voluntary codes that are adopted and enforced by numerous regulations. However, over the last few decades, some Canadian provinces have adopted them as part of their safety measures. Therefore, the idea of installing rapid shutdowns on solar systems has not been adopted by all the Canadian cities.
The Rapid shutdown is one of the most controversial requirements in Canada, with some individuals claiming that it shouldn’t be included in the CEC. In fact, most professionals believe that the fire departments should enforce it. Plus, some first respondents never vent the roofs when trying to access a burning building.
3. The Location of the Rapid Shutdown Switch
For easy access, the CEC requires that the rapid shutdown switch of single dwelling units be installed at your utility meter. The CEC also stipulates that all the other buildings other than the single dwelling units must have two rapid shutdown switches. One shall be installed at the utility meter while the other will be at the building’s permanent access to the roof or 9 meters from the system’s array. This way, firefighters can switch it off together with the home’s electricity. Installing the switch in a specific position will make it possible for the firefighters to locate it even when the homeowner is not around.
4. If the Utility Disconnect Serves as Rapid Shutdown, It Must Be Labeled Correctly
Some systems use optimizers or micro-inverters with rapid shutdown capabilities. Therefore, if you have installed a dual function inverter, then it should be well labeled. This will make it easy for the firefighters to know how to shut down the photovoltaic system within seconds.
5. All Inverters Don’t Have Rapid Shutdown Capabilities
A considerable percentage of the inverters are compliant with the CEC requirements; therefore, they come with module-level rapid shutdown systems, while others need an additional component to be able to function correctly. Some of the power optimizer and microinverter systems like SolarEdge and Enphase come with in-build shutdown capabilities. Therefore, with these brands, you won’t need an additional component.
Other brands like Tigo and SMA America have produced their shutdown components that must be installed at the back of the solar panels. Therefore, don’t assume that every inverter in the market has rapid shutdown capabilities.
Final Thoughts
Even though the idea of installing rapid shutdown switches is still very highly debated in Canada, it is a very crucial function. The rapid shutdown function was designed to protect the first respondents in case of fire. These codes have made it safer and easier for the firefighters to access a burning house and save everyone in the building, including the property itself. Therefore, installing a certified rapid shutdown system in your home can help keep you and your entire family safe in case of fire.
