2017 690.12(B)(2)(2)- NON-METALLIC IDEAS

[310 BLAZE IT]

Anyone know of non-conductive racking systems that work with frame-less modules?
How about non-conductive rapid shutdown devices so they can be located within 1' of array (can't have conductive parts within 8m)

Someone needs to start making these come Jan 1 2019. Frame-less module economics start to work if you automatically have 1-3% less losses than other systems because of no optimizer, get to keep using an economical inverter like a Chint or Sungrow, have a superior warranty on the panels, much simpler communications system.

Problems with this idea are: Rooftop units needing an 8.5' setback, wire management without metallic parts, PVC conduit expansion fittings... please leave your negative feedback and/or love for micro-inverters/optimizers

 

[jaggedben]

Thoughts, in random order:

• The closest thing I can think of to what you're suggesting that I've seen in the real world is ballasted systems with plastic ballast trays. But all the one's I've seen still have metal clamps designed for metal module frames. I would imagine that getting the same engineering strength for wind loads with non-metallic parts has its difficulties.
• I thought frameless modules were more expensive. Maybe I'm wrong?
• How about, instead of a full blown optimizer with any buck/boost or data communications or other whatnot, just a semiconductor switch inside the module J-box that drops the voltage to the really low amount when it loses the signal from a rapid shutdown controller?
• Yeah, I have a fair amount of love for optimizers and microinverters. Economics aside, the gains from mitigating shade and module mismatch surely outpace the efficiency losses, especially for optimizers.

 

[Carultch]

Anyone know of non-conductive racking systems that work with frame-less modules?
How about non-conductive rapid shutdown devices so they can be located within 1' of array (can't have conductive parts within 8m)

Someone needs to start making these come Jan 1 2019. Frame-less module economics start to work if you automatically have 1-3% less losses than other systems because of no optimizer, get to keep using an economical inverter like a Chint or Sungrow, have a superior warranty on the panels, much simpler communications system.

Problems with this idea are: Rooftop units needing an 8.5' setback, wire management without metallic parts, PVC conduit expansion fittings... please leave your negative feedback and/or love for micro-inverters/optimizers

Any reason you are restricted to not having conductive parts within 8 meters of the array? Rapid shutdown in general doesn't restrict you from using metallic racking, wiring structures, or other metal parts that do not intentionally carry current, in the context of the array. I doubt that a clamping system for a frameless module could be reliably and economically made out of nonmetal parts. The gaskets would of course be nonmetallic, but the main structure and cap strip that supply the pressure to hold the gaskets tight...unlikely.

As for 2019 Rapid shutdown, the NEC is essentially prescribing either module-level (or module pair level) power electronics in some form or another, when on a rooftop, to stay within the 80 Volt limit. Either that, or wire all your modules in parallel with trunk cables the size of a tree trunk. This could be power processing electronics like optimizers or microinverters, but it could also just be a switching unit at the module level. From what I've seen on the latter, it costs about as much as the additional cost to do an optimizer system anyway, so you might as well get the module-level power processing capability, instead of just an on/off switching unit. In any case, conventional systems that have 600V or 1000V strings with directly wired modules, are going to be restricted to systems that are not on buildings.

 

[electrofelon]

As for 2019 Rapid shutdown, the NEC is essentially prescribing either module-level (or module pair level) power electronics in some form or another, when on a rooftop, to stay within the 80 Volt limit.

Someone mind getting me up to speed? First what is this 2019 date? Its in the middle of code cycle. Second am I reading this correctly that the NEC will require rapid shut down at the module level when on buildings?? You've got to be kidding.....

 

[ggunn]

...am I reading this correctly that the NEC will require rapid shut down at the module level when on buildings?? You've got to be kidding.....

He's not kidding.

 

[Carultch]

Someone mind getting me up to speed? First what is this 2019 date? Its in the middle of code cycle. Second am I reading this correctly that the NEC will require rapid shut down at the module level when on buildings?? You've got to be kidding.....

The requirement of 690.12(B)(2) shall become effective January 1, 2019.

Essentially it is a grace period for products to get up to speed. Also, it is not necessarily module level shutdown, but in most cases it is. It is shutdown to 80V within the array.

 

[SolarPro]

In a nutshell: 1.) UL is developing a new rapid shutdown standard for NEC 2017. Module-level devices will undoubtedly meet this standard. I suspect other listed options will be available as well. 2.) The new requirements for controlling conductors within the array have delayed enforcement; this is the January 2019 date. 3.) Until then, the main difference between the NEC 2014 and NEC 2017 rapid shutdown requirements is that the 10' boundary outside the array shrinks to 1'.

See: Module-Level Rapid Shutdown for Commercial Applications

 

[electrofelon]

Thanks

 

[electrofelon]

He's not kidding.

but if you are kidding, then he could be kidding..... :blink:

 

[ggunn]

but if you are kidding, then he could be kidding..... :blink:

Alternative facts?

 

[wwhitney]

Here's the text under discussion in this thread:

PV arrays with no exposed wiring methods, no exposed conductive parts, and installed more than 2.5 m (8 ft) from exposed grounded conductive parts or ground shall not be required to comply with 690.12(B)(2).

Cheers, Wayne

 

[310 BLAZE IT]

Thoughts, in random order:

• The closest thing I can think of to what you're suggesting that I've seen in the real world is ballasted systems with plastic ballast trays. But all the one's I've seen still have metal clamps designed for metal module frames. I would imagine that getting the same engineering strength for wind loads with non-metallic parts has its difficulties.
• I thought frameless modules were more expensive. Maybe I'm wrong?
• How about, instead of a full blown optimizer with any buck/boost or data communications or other whatnot, just a semiconductor switch inside the module J-box that drops the voltage to the really low amount when it loses the signal from a rapid shutdown controller?
• Yeah, I have a fair amount of love for optimizers and microinverters. Economics aside, the gains from mitigating shade and module mismatch surely outpace the efficiency losses, especially for optimizers.

• Yes, I use Ecolibrium Ecofoot 2+ very often... going to discuss this idea with the vendor because they are closest to making this possible.
• They are expensive but this may be an opportunity for them to be justified and give manufacturers an opportunity to scale their use bringing price down. Longer and better warranty on them, less material (silver, aluminum) not sure of their heat characteristics though.
• Yes there are Tigo optimizers which are exactly this. Let's not forget the increased complexity and cost of the control system because of these.

Thanks Wwhitney, I should have cited the code section mentioned in the OP. I'm looking for a way around the rapid shut down requirement within the array boundary, because who knows what the exact UL standard will be. These control systems are ridiculously annoying and labor-intensive. If I am responsible for O&M on a system that I design, I do not want optimizers if there's a way around it and my managers very much think this way. I think problems in the industry are being created because most who design systems do not do O&M.