DC disconnect with rapid shutdown?

[badwithusernames]

I am in the (hopefully) home stretch of system design for my grid tied system here in NJ. I have been back and forth with my local township and the utility PSEG about a fe questions. The township inspector is useless at best. The utility won't give me a straight answer. So, here is my question:
NJ is currently held to 2017 NEC, which requires a rapid shutdown system to turn off all DC current at each panel. It would seem logical that this may do away with the need for an additional physical DC disconnect, though I admit I haven't read the 2017 code entirely to find out. As it is, 24 Tigo TS4 units and the transmitter are adding an extra thousand bucks, I'd rather not buy the disconnect if it isn't needed.
By design, with the rapid shutdown system, the AC disconnect will kill everything. So? Thoughts?

[Mike90250]

Above my pay grade. Sorry

[solarix]

DC disconnects are built into all inverters, but the 2017 code adds a requirement for disconnection at each module. The best way to deal with this in my view is the TIGO TS4 rapid shutdown units in combination with a "Sunspec" capable inverter to control them such as the latest -41 version of the SunnyBoy line. I hate this as it means putting electronics on our hot Arizona roofs, but at least when one of these fails, they fail safe with only the rapid shutdown capability being jeopardized.
And yes, to answer your question - when the inverter goes down either due to a grid outage or an AC breaker trip, the array is shut off and if there are RS units, each module is shut off.

[badwithusernames]

Thank you. The township inspector said that he wanted a DC shut off located outside the building next to the AC disconnect, and then did not clarify when I asked him to. The inverter does have a DC disconnect, but it is located in the basement with the inverter. I mentioned the rapid shut down that turned off the DC voltage when the AC voltage was shut down, and he just sort of stared into space...
I don’t really feel like challenging my township inspector, but I also don’t feel like spending money for nothing

[PVAndy]

You can also accomplish this with SolarEdge optimizers. The AC Disconnect needs to have a Rapid Shutdown Switch label on it. oth SolarEdge have applications notes for the AHJ. Also keep in mind that MC-4 connectors are listed as non load break DC Disconnects;

Andy

[solarix]

I often joke how solar power is so "evil" there needs to be six ways to Sunday to turn it off.....

[badwithusernames]

You can also accomplish this with SolarEdge optimizers. The AC Disconnect needs to have a Rapid Shutdown Switch label on it. oth SolarEdge have applications notes for the AHJ. Also keep in mind that MC-4 connectors are listed as non load break DC Disconnects;

Andy

Andy, good idea. I am using the Tigo TS4 optimizers/ rapid shutdown modules, and I'll mention labeling the AC disconnect to show it also operates the rapid shutdown. I honestly think the inspector has no idea what the rapid shutdown even is. If I could have gotten dose clarification from the utility he would have just gone along with whatever they specified. Argh

[scrambler]

My inverter has a shutdown switch that switches off both DC and AC, and we are powering the Tigo CCA using the inverter AC out so when the inverter is shutdown it triggers Tigo rapid shutdown.

As a result, this shutdown switch on the inverter does it all, and the solution that was decided upon was to wire a remote shutdown switch by the meter in series with that Inverter main shutoff switch, thus eliminating the need for several Switches by the meter.

Now we did run into some problems with the inverter, as the long wiring of the remote shutdown switch was causing some weird interference to the shutdown circuit, so the manufacturer is working on a fix for that.

But overall, this sounds like a simple and rational way to do it.

[bcroe]

As a result, this shutdown switch on the inverter does it all, and the solution that was decided upon was to wire a remote shutdown switch by the meter in series with that Inverter main shutoff switch, thus eliminating the need for several Switches by the meter.

Now we did run into some problems with the inverter, as the long wiring of the remote shutdown switch was causing some weird interference to the shutdown circuit, so the manufacturer is working on a fix for that.

What is a REMOTE SHUTDOWN SWITCH? Bruce Roe

[scrambler]

What I meant is that everything can be shutdown outside by the meter (which is far away from the inverter) with a single Switch.