Rooftop Shutdown Equipment

[Pau lRisberg]

When we last considered rooftop shutdown issues (at NABCEP 2014 Conference in Denver), there were questions about the logical nature of providing module level shutdown capability, most likely to be mandated by the industry, and relatively easily instituted by module manufacturers. Here is optional equipment that gets the job done. I predict the next round of NEC will require it on commercial atray's. That being said, is it really a good cost/benefit solution? I would venture that only allowing solar on sprinklered structiures would be far cheaper and more effective.

http://ep-us.mersen.com/products/catalog/line/greeneye-greenbrain/

 

[renosteinke]

Solar power offers nothing new, as compared to other secondary power sources, save one thing: You can't turn it off. Sort of like a battery. How can you LOTO the sun?

With that in mind, how would YOU want a system designed? So that a fault in one panel brings down the entire system?

That's why the micro-inverter approach makes such sense. No backflow. Each section stands alone. You can add or remove with a minimum of risk.

Personally, I'd rather handle / work on something that was only capable of zapping me with a few amps of relatively low-voltage power. I'm not too keen on dealing with a 600VDC, 400-A feed to the very first disconnect or fuse.

Likewise, I'd hate to see my entire $$$$ array melt down simply because one of the wafers in panel #342 decided to crap out.

Should such be specified by code or product standards? I'm inclined to say "no." Not every good idea is a matter for the law. The technology is quite new, and we're likely to see all manner of developments in the next decade - improvements that would only be hindered by code. Why do you think the railroads haven't changed much in a century? Because everything got defined by law.

As it is, "the law" has already perma-slewed the "alternative energy" market, with it's quotas and subsidies. Sort of makes you wonder how automobiles ever replaced horses, without a government mandate.