Rapid shutdown and code when swapping to hybrid inverter

[SolarJax]

My electrician has a customer who wants to replace their old Fronius inverter with a new hybrid inverter and add backup power. This is straight forward, except the system was installed ten years ago, before rapid shutdown was required.

Since this isn't common (yet) I haven't found any information on whether we'll be required to add rapid shutdown or not. If so, it's a much more involved project.

I'm calling the AHJ (Arvada, CO) and will submit a request to Xcel for more information, but Xcel can take months to respond to a request. I'm hoping someone here has an instinct, if not a definitive answer.

And yes, I recognize that ultimately the AHJ and Xcel will decide, but if they hadn't considered it, I'd like to be armed with information.

Thanks!

 

[ggunn]

My electrician has a customer who wants to replace their old Fronius inverter with a new hybrid inverter and add backup power. This is straight forward, except the system was installed ten years ago, before rapid shutdown was required.

Since this isn't common (yet) I haven't found any information on whether we'll be required to add rapid shutdown or not. If so, it's a much more involved project.

I'm calling the AHJ (Arvada, CO) and will submit a request to Xcel for more information, but Xcel can take months to respond to a request. I'm hoping someone here has an instinct, if not a definitive answer.

And yes, I recognize that ultimately the AHJ and Xcel will decide, but if they hadn't considered it, I'd like to be armed with information.

Thanks!

Unfortunately, there is nothing in the NEC that can help you. It is all in the hands of the AHJ and the POCO whether or not they will grandfather in the lack of RSD as being compliant.

 

[wwhitney]

But if the goal is just to add battery backup, then you have the option to add an AC-coupled system, rather than replace the inverter and use a DC-coupled system. Presumably not touching the existing PV system would mean it would not be subject to modern RSD requirements.

Cheers, Wayne

 

[SolarJax]

But if the goal is just to add battery backup, then you have the option to add an AC-coupled system, rather than replace the inverter and use a DC-coupled system. Presumably not touching the existing PV system would mean it would not be subject to modern RSD requirements.

Cheers, Wayne

Agreed, but since the inverter is already a decade old, it's likely to fail in the coming years. But, if they would require rapid shutdown, I'd recommend swapping the Fronius and AC coupling as well. It's far less hassle.

Thanks for the replies!

 

[pv_n00b]

Agreed, but since the inverter is already a decade old, it's likely to fail in the coming years. But, if they would require rapid shutdown, I'd recommend swapping the Fronius and AC coupling as well. It's far less hassle.

Thanks for the replies!

Every time I have seen a repower of an existing PV system it means bringing it up to the current code. YMMV but don't be surprised if you have to add RSD. This is more a question to the area AHJ and not the utility so you should be able to get a quick response.