So how bad are string inverters vs microinverters?

[Mike 134]

Foggy, do they allow the roof overhang to be part of that 3' rule in your location? Some jurisdictions out in CA (no surprise) do not. I have a gable roof so I had to provide a path on both sides of the array.

[foggysail]

OK, I agree with all of you, the rapid rule is a bunch of crap, now to move onwards. So I said to Self, go the grid tie micro inverter route and be done. After complying with more fire department crap, this time the 3' pedestrian travel lane. I hoped to use Canadian Solar panels, the 450 W bifacial with a VOC of 49.1V to maximize my solar array's power density and so far..................I CANNOT FIND A grid tie micro inverter that I want to use. I don't know how much latitude experts allow for upper voltage limits, but no way will I stick an inverter into the array that has a 50VDC maximum input when the panels have 49.1 VOC.

Yes... anxious for suggestions and damn it, this could force me to a string inverter.

Thx

[solarix]

If you want to get the code changed to remove rapid shutdown, go to FixMLSD.com and join this grass roots organization.

[Mike 134]

This whole rapid shut down crap is a scam introduced into your regulations via sponsorship from micro and optimiser manufactures and was designed to benefit 2 equipment retailers, thats the truth of it, they tried to do the same in Australia and we fought them tooth and nail and the regulators came to see the sense in the industry s argument against it, I think its a matter of time before they get rid of these stupid regulations in the States, just my 2 cents, (rant over)

Obviously you have never felt what line voltage does to your body. For those folks that do not want rapid shutdown on their solar system they should be able to sign a wavier telling the fire dept not to respond to a fire during daylight hours at their house. Makes everyone happy, you don't have the added expense of rapid shutdown and the fire dept by only responding in the darkness has no worries about a 400Volt electric shock. Win Win don't you think?

[SunEagle]

This whole rapid shut down crap is a scam introduced into your regulations via sponsorship from micro and optimiser manufactures and was designed to benefit 2 equipment retailers, thats the truth of it, they tried to do the same in Australia and we fought them tooth and nail and the regulators came to see the sense in the industry s argument against it, I think its a matter of time before they get rid of these stupid regulations in the States, just my 2 cents, (rant over)

Probably another reason solar is so expensive here in the US. There is a lot of "safety" equipment required per NEC which may provide some security but mostly just increases the cost of an installation.

[foggysail]

This whole rapid shut down crap is a scam introduced into your regulations via sponsorship from micro and optimiser manufactures and was designed to benefit 2 equipment retailers, thats the truth of it, they tried to do the same in Australia and we fought them tooth and nail and the regulators came to see the sense in the industry s argument against it, I think its a matter of time before they get rid of these stupid regulations in the States, just my 2 cents, (rant over)

OK, fair enough!!! Now when I get my poop together I should tell the town's electrical inspector, ''HEY BUTCH--- I NEED THAT SOLAR WIRING PERMIT NOW, AND THAT RAPID SHUTDOWN YOU DEMAND IS NOTHING MORE THAN A BUNCH OF CRAP''.............. who will tell me to check 2020 NEC 690.12

Your logic is fine and I would agree IF there was an operating solar system on my roof as I type. Don't get your hopes up, once something gets into code, it only grows, not goes away.

[solarix]

Solar Pete: I totally agree... Rapid shutdown is of virtually no benefit to the fire services and causes a lot of expense and greatly decreases the reliablity of a solar install.

[solar pete]

This whole rapid shut down crap is a scam introduced into your regulations via sponsorship from micro and optimiser manufactures and was designed to benefit 2 equipment retailers, thats the truth of it, they tried to do the same in Australia and we fought them tooth and nail and the regulators came to see the sense in the industry s argument against it, I think its a matter of time before they get rid of these stupid regulations in the States, just my 2 cents, (rant over)

[foggysail]

Here I go again with still limited knowledge..........

I agree that a greater number of widgets will increase the failure probability. And yes, a failed micro is going to be a BPITA to identify and repair. For those reasons I started searching for string inverters that will satisfy a system that I hope to install this summer onto my home. But then I realized a string inverter does not solve all problems such as the current requirement for rapid shutdown.

OK, that can be solved with shutdown devices such as those offered by Tigo. But what if a shutdown device fails? I will have a similar search, find and repair as I would have with micros. Now as to optimizers, I have to ask why? Optimize deliver DC to a string inverter when a micro will do the optimization without the need for a string. And they are buried under panels just as mircos. Think failures/repairs!

I find myself behind on Code since I let my licenses expire so I just ordered a 2020 version. From what I understand, wiring DC voltages inside a building greater than 30V OR 8 A has to be in metal tubing! So what advantages do optimizers offer or for that matter, strings?????

As I type I believe there are microinverters in my future. Just my humble thoughts, at this time anyway

[foggysail]

Yes, and now with Rapid Shutdown codes being applied, you have a choice of micros or optimizers . Optimizers are somewhat simpler, and less likely to fail long term

ay.

[J.P.M.]

That's fair. But if there are customers out there that say "I understand the site's not ideal, but I still want solar" that's also a valid request.

IMO the job of an ethical solar installer is to give the customer good advice on the pros and cons of each system they offer - then let the customer make the final decision. (Subject to what's available and supportable from the installer's perspective of course.)

Sales people and the outfits they work for are not the moral and ethical guardians of the universe. If they were, there would be a lot fewer of them and they'd be a lot poorer. That would probably be good for humanity but bad for capitalism.

I appreciate and respect your opinion and in some, perhaps many situations, I agree. But there is more to selling than that. There is a moral and ethical component that comes in at times such as when you look in the mirror and know you just screwed someone for a commission.

Before I changed professions to engineering (and took a pretty healthy income hit BTW) I spent 10+ years of my earlier working life as a commission sales rep. peddling industrial process equipment. I learned a lot about human nature from pros and mentors in the sales game including how hard it can be to keep the moral compass pointed in the right direction in the face of customer ignorance.

Sales people who stick with it and learn the profession probably start out honest and stay that way in most selling situations.

But one thing I know from the experience is that there are a lot of people and companies in the world who are naive, can be easily manipulated and separated from their assets by a lot of peddlers who take advantage of such people and their ignorance. Now, I like a buck as much or more than the next person, but sometimes it was challenging to keep my moral compass pointed in the right direction when dealing with such people and organizations.

I believe my experience was probably typical.

If so, a lot of money is made off people's ignorance.

If that were not true, I'm pretty sure there would be far fewer PV arrays on homes and those that did exist would be a lot smaller and better designed.

[SunEagle]

That's fair. But if there are customers out there that say "I understand the site's not ideal, but I still want solar" that's also a valid request.

IMO the job of an ethical solar installer is to give the customer good advice on the pros and cons of each system they offer - then let the customer make the final decision. (Subject to what's available and supportable from the installer's perspective of course.)

In some cases the words "ethical" and "solar installer" should not be used. There are a percentage of all sales people that just want to make a sale and don't care who they hurt.

[jflorey2]

If I had a location that needed micros or optimizers to make it work, I'd seriously question the viability of that location as a candidate for a successful solar installation.

That's fair. But if there are customers out there that say "I understand the site's not ideal, but I still want solar" that's also a valid request.

IMO the job of an ethical solar installer is to give the customer good advice on the pros and cons of each system they offer - then let the customer make the final decision. (Subject to what's available and supportable from the installer's perspective of course.)

[bcroe]

That may be but at least as a kid I learned and know the difference between a pronoun and a contraction.

So did I. One more item not discussed much. Using micros will much
increase the length of the AC wiring, raising the line voltage at the
micro inverters. Here long AC lines and a Power Company always
inching up the voltage for their own efficiency, caused me grief from
high line shutdown. The cure was a combination of installing much
larger wire, bugging the PoCo till they brought the voltage down, and
reprogramming the inverter voltage monitors. Bruce Roe

[J.P.M.]

Optimizers are somewhat simpler, and less likely to fail long term

That seems like damning with faint praise to me.