As of January 1st, 2020, several states have started enforcing the NEC 2017 or NEC 2020. You can find out which version of the NEC code is being enforced in your state by using the NEC adoption map below:
NEC® in Effect 2/1/2020
NEC 2017 and beyond requires a module-level rapid shutdown solution for roof mounts, although there can be exceptions such as installing on a roof of an uninhabitable structure such as a shed or carport. If you’re not sure whether your local jurisdiction is enforcing rapid shutdown or whether it’s required for your structure, give them a quick call to double-check!
Where is the National Electrical Code® in effect?
If you need to comply with rapid shutdown requirements, you can either:
If you don’t need an all-purpose solution, Tigo offers several MLPE devices that allow you to choose the specific features that fit your needs and budget. Below are some of the options they offer:
Lowest cost NEC 2017 rapid shutdown solution
Lowest cost NEC 2017 rapid shutdown compliance
Lowest cost NEC 2017 rapid shutdown compliance
Module-level monitoring and optimization
Automatic or manual shutdown
Compatible with selective deployment (Mix and match)
Rapid shutdown compliance at the lowest cost
If you're looking to save the most money on your PV system and need to comply with the rapid shutdown requirement, the TS4-A-F is the device for you. Keep in mind, this unit doesn't provide any additional benefits, such as optimization or module-level monitoring. The TS4-A-F is ideal for roofs that have very little to no shading issues and are located in areas where you get mostly sunny days.
An extra feature of this device is it's built-in over-temperature protection. This means that if you live in an area that can reach very high temperatures, the system can help prevent fires due to overheating by shutting down the system when it determines there is a fire hazard for your system and roof. This feature is also included in the TS4-A-O and TS4-A-S devices.
Rapid shutdown with module-level monitoring
The TS4-A-S offers module-level monitoring and fire safety, which allows you to monitor (through your computer or smartphone) the status and production of each panel in real-time. This feature can give you peace of mind knowing that your system is performing as expected, and allow you to take swift action if it is not.
A solar panel can underperform for several reasons, such as receiving physical damage from bad weather, birds and rodents, shading from vegetation growth near the array, or simply due to a manufacturing defect. Oftentimes these issues go unnoticed for extended periods of time, resulting in production loss and therefore financial loss on your investment. With module-level monitoring, you will be able to quickly notice and pinpoint when and where a solar panel in your array is underperforming, meaning you will not have to spend time troubleshooting your system or checking every panel to locate the issue. This will result in savings both by reducing system downtime and lowering maintenance costs.
Rapid shutdown with monitoring and optimization
The Tigo TS4-A-O is an all-in-one device. In addition to having module-level monitoring and fire safety, it has the added benefit of module-level optimization. Although, this comes at a higher cost than the other available options.
Module-level optimization means that your system will generate as much power as it can. Optimizers allow each panel to perform at its optimal level, and to send its energy to the inverter without it being affected by lower-producing panels connected in the same string. Getting the most out of your solar PV system means you will reduce the payback time.
If your array doesn't have any shading issues and you live in an area that is mostly sunny throughout the year, you may not need module-level optimization.
The best application for optimizers is for arrays that have shading issues in sections of the array or the whole array at a different time of day, for example, shade from a tall electricity pole, a tree, power lines, or an antenna. If the shading issues only affect parts of the array, you can reduce the total cost of your system by using optimizers only in the areas of the array that need optimization, that is, you can restrict the use of TS4-A-O devices to the areas affected by shade, and then use TS4-A-S devices in the areas that are not affected by shade. This is a great feature allowing you to mix and match devices and is exclusive to Tigo optimizers -- this is not an option for other popular solutions such as SolarEdge DC optimizers. The Tigo TS4-A-O and Tigo TS4-A-S will communicate with one another and together will give you a rapid shutdown compliant installation.
It is important to note that you cannot mix TS4-A-O with TS4-A-F devices in the same installation, as they have different types of communication and are not compatible with one another.
If you have any questions about Tigo products or need assistance choosing a particular Tigo MLPE, please don’t hesitate to contact the RENVU support team.