Scoob-SanDiego
New Member
I have been planning a basic solar system for a friend.
Not permitted but still safety minded.
As part of the project, I evaluated using Tigo products to implement Rapid System Shutdown (RSS).
On the face of it, it looked prohibitively expensive but upon calculation, setting up basic RSS using Tigo for a 10x 400W panels + EG4 6000XP all-in-one inverter would come to about $325 total!
In this post, I will give
Rapid Shutdown System (RSS) which is a requirement for a solar system to pass code inspection. While we can get away with doing our own solar system and not tell anyone about it... no inspections, no government requirements, those requirements were put in place for safety reasons. So it is a good idea to educate ourselves to the RSS specification / requirements and where compatible with our budget, implement those requirements in our systems.
The lower end of all in one inverters from China do not comply with RSS requirements. But Products from EG4 are rapidly becoming compliant (at the time of writing, all all-in-on inverters except the 3000K comply with RSS).
If using a RSS compliant inverter (ex EG4 6000XP), then the additional cost of making our system RSS compliant can be more reasonable.
When you consider that the system with an EG4 upright battery, the EG4 6000XP and the panels is around $8K, the extra $322 is almost insignificant.
And considering that strininging 10x 400W solar panels together will get you nearly 400V on the string, it's a pretty neat device to keep you SAFE... all your panels are at 0V UNTIL you put 12V power to the Tigo pure signal emitter (which will tell the modules behind the solar panels to allow the voltage to flow through).
Note: In my sample system, the EG4 600XP, there is a built-in PV disconnect but code compliance requires that there be
a PV disconnect OUTSIDE so fire fighters can safely disconnect the PV. This seems unnecessary if you have a RSS system
as it will bring the voltage output if each individual panel to near 0V which in and of itself is much safer than a PV disconnect.
Personally, I just put the disconnect mushroom button outside where I would otherwise put the PV disconnect.
But if you want to play the game, you would add an extra $90 for an outdoors PV interrupt switch
Because the EG4 6000XP has built-in RSS capability, it includes a built-in 12V power supply.
No need to purchase the kit with the green transmitter an the box + din rail + power supply.... Just purchase the green RSS transmitter and house it either directly in the 6000XP chassi or in the connection box between it and the battery. If you use one of the stand up EG4 batteries, it is RSS ready and will even trip the battery breaker when RSS is activated.
Installation video:
Another excellent post from this forum:
Restore power AFTER a RSS shutdown:
RSS AND monitoring/optimization models: (TS4-A-O):
I hope this helps some of you out there!
- Christian
Not permitted but still safety minded.
As part of the project, I evaluated using Tigo products to implement Rapid System Shutdown (RSS).
On the face of it, it looked prohibitively expensive but upon calculation, setting up basic RSS using Tigo for a 10x 400W panels + EG4 6000XP all-in-one inverter would come to about $325 total!
In this post, I will give
- a brief overview of RSS,
- a summary of the parts and cost for my small sample DIY solar system
- Some links on how to connect the Tigo system to the EG4
- Some NEC links regarding RSS
- An overview of the Tigo lineup
- Some links to the various Tigo products
Rapid Shutdown System (RSS)
RSS is a requirement to shut down the electricity production at the solar panel level under emergency shutdown conditions. Practically, if you have a RSS compliant all-in-one inverter and battery(ies), if someone hits the emergency button (e.g. fire fighters), within seconds the voltage out of the PV string will drop down to 0V, the battery will shutdown (trip its own breaker) and the inverter will shutdown, making the premise electrically safe for first responders.Rapid Shutdown System (RSS) which is a requirement for a solar system to pass code inspection. While we can get away with doing our own solar system and not tell anyone about it... no inspections, no government requirements, those requirements were put in place for safety reasons. So it is a good idea to educate ourselves to the RSS specification / requirements and where compatible with our budget, implement those requirements in our systems.
The lower end of all in one inverters from China do not comply with RSS requirements. But Products from EG4 are rapidly becoming compliant (at the time of writing, all all-in-on inverters except the 3000K comply with RSS).
If using a RSS compliant inverter (ex EG4 6000XP), then the additional cost of making our system RSS compliant can be more reasonable.
Sample system cost summary:
In my planned small system (10 x 400W solar panel connecting to EG4 6000XP), I will need to get the following items to make it RSS compliant:- 1X. - 2023 NEC Code Sticker Pack | UL Listed. $21
- 1X. - IMO Emergency Stop Button | Twist to release | 500VAC | 1NO + 1NC $27
- 1X - Tigo RSS Transmitter - Pure Signal Single Core (No Enclosure) | Din Rail Mount $44
- 5x - Tigo TS4-A-2F | 2 Module Rapid Shutdown | 20A (Isc), 1000W, 1500VUL $46/each. $230.85 total
When you consider that the system with an EG4 upright battery, the EG4 6000XP and the panels is around $8K, the extra $322 is almost insignificant.
And considering that strininging 10x 400W solar panels together will get you nearly 400V on the string, it's a pretty neat device to keep you SAFE... all your panels are at 0V UNTIL you put 12V power to the Tigo pure signal emitter (which will tell the modules behind the solar panels to allow the voltage to flow through).
Note: In my sample system, the EG4 600XP, there is a built-in PV disconnect but code compliance requires that there be
a PV disconnect OUTSIDE so fire fighters can safely disconnect the PV. This seems unnecessary if you have a RSS system
as it will bring the voltage output if each individual panel to near 0V which in and of itself is much safer than a PV disconnect.
Personally, I just put the disconnect mushroom button outside where I would otherwise put the PV disconnect.
But if you want to play the game, you would add an extra $90 for an outdoors PV interrupt switch
Installation of Tigo with EG4 systems:
The instructions below should apply to EG4 6000XP / 12K / 18K but NOT the 3000W yellow model which is not RSS compliant.Because the EG4 6000XP has built-in RSS capability, it includes a built-in 12V power supply.
No need to purchase the kit with the green transmitter an the box + din rail + power supply.... Just purchase the green RSS transmitter and house it either directly in the 6000XP chassi or in the connection box between it and the battery. If you use one of the stand up EG4 batteries, it is RSS ready and will even trip the battery breaker when RSS is activated.
Installation video:
Another excellent post from this forum:
Operation of RSS:
Triggering RSS: Press the mushroom button (which triggers a gpio on the EG4 inverter) OR the EG4 software triggers the RSS condition inside the 6000XP,- The inverter will turn off the power to the 12V RSS transformer.
- This will in turn have the panel mounted tigo TS4 units passively shut down the voltage from EACH panel
- i.e. No RSS transmitter signal = 0V output from each panel.
- The inverter will also signal the battery BMS. IF you have an EG4 stand up battery (or presumably some of the rack ones) or some other RSS ready battery that talks to the EG4 inverter bus, it will SHUT DOWN the battery by tripping the battery's breaker.
- Finally, the inverter will shut down (if off grid) or will stay powered up but not producing electricity if connected to the grid.
Restore power AFTER a RSS shutdown:
- If you have an EG4 stand up battery, you must FIRST reboot the battery (reboot button) BEFORE you can flip the breaker back on.
- Then you power on your inverter (or if on utilities, read the manual or power cycle/reboot the inverter)
- Once powered on, the inverter will power the RSS transmitter which will tell the TS4 units to unblock the voltage from the panels.
- The 6000XP has a built-in PV interrupt switch.
- Code / Regulations require an outside PV interrupt switch.
- But if you have a mushroom RSS Emergency Button, it WILL turn off ALL solar power MORE completely than just a PV interrupt anyway.
- I could only see the benefit of an external PV interrupt if you want to work inside your 6000XP during the day and avoid having 500V coming into the inverter while you work!!!!! But again, I think hitting the RSS E-button is. a SAFER option when working inside your inverter!
- You can also take a belt and suspender approach and use BOTH RSS and the PV switch.
NEC 2017 / 2020 require Rapid Shutdown System (RSS)
- Overview:
- 30sec after RSS initiation, power withing the array must be < 80V and outside the array < 30V
- Comment:
- Given that DC doesn't spark until about 80V, then a 60V PV string setup like mine does not warrant an RSS (even if code would demand it... safety does not)
- Details:
- NEC code (look at section 690, PV stuff... about 16 pages):
- https://www.nfpa.org/codes-and-standards/7/0/70
- LOGIN (free membership)
- Select edition and click Select Edition
click "Free Access" button.
Overview of Tigo Products:
Tigo seems to offer 3 types of products.- Rapid Shutdown System (RSS) modules
- Optimisation modules (i.e. allows you to bypass a panel(s) that is in the shade to still maximize the output of the array.
- Monitoring of larger systems
- Some combination of the above. The system I described in the example above was strictly RSS, no monitoring and no optimization. It is the simplest and cheapest option.
- Youtube Tigo page: https://www.youtube.com/@Tigo_Flex_MLPE
- Tigo has RSS modules and/or RSS + monitoring/optimizing modules
- All devices connect panels in series and by default DON'T let any voltage/current through UNLESS the transmitter signal is present and ON.
- There is an external transformer and transmitter which sends a singal OVER the solar cable coming back from the panels on the roof.
- If you use the monitoring / optimizing modules, then you need an extra box.. one for every 300 modules? position within 10Meters etc... not a big deal
Best Overview video of Tigo products.
RSS AND monitoring/optimization models: (TS4-A-O):
- https://www.tigoenergy.com/product/ts4-a-o
- $44 - https://signaturesolar.com/tigo-ts4...own-15a-700w-1500vul-1000viec-mc4-1-2m-cable/
- This takes care of bypassing any module that is in the shade... keeps your string productive even with partial shading.
- App and web based monitoring. Very cool and clever.
- Has RSS
- Requires extra gear (takes care of monitoring AND RSS)
- You need ONE Tigo Access Point (TAP) per roof (240 modules).
- https://www.tigoenergy.com/product/tigo-access-point
- The TAP is mounted behind a panel on the roof
- The TAP communicates with the tigo modules through a proprietary mesh network.
- It has to be within 10m of ONE TS4, then the TS4 connect from one to another using that mesh system.
- You need one Cloud Connect Advanced (CCA)
- https://www.tigoenergy.com/product/cloud-connect-advanced
- The CCA can connect to up to 7 TAP
- The CCA is at ground level (close to power and wifi) and is connected to the TAP(s) using a RS-485 cable.
- The kit with both:
- $300. https://signaturesolar.com/tigo-tap-din-rail-ps-outdoor-enclosure-kit/
- Installing the CCA / TAP. https://www.youtube.com/watch?v=bD41ybJPyY8
- Manual RSS switch connection:
- You need ONE Tigo Access Point (TAP) per roof (240 modules).
I hope this helps some of you out there!
- Christian
My grid only house was built in 2010. Not saying there aren’t any with external disconnect, just haven’t seen any yet.
