Inverter on roof?

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GerryB

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Location
woodbridge, ct. USA
A friend said his engineer is quoting 690.12 for the rapid shutdown and that the inverter (with rapid shutdown) has to be on the roof, or I guess not farther then 10 feet from it. We just adopted the 2014 NEC. Is this not quite right?
 
GerryB said:
A friend said his engineer is quoting 690.12 for the rapid shutdown and that the inverter (with rapid shutdown) has to be on the roof, or I guess not farther then 10 feet from it. We just adopted the 2014 NEC. Is this not quite right?
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Putting the inverter near the array is one way to meet the rapid shutdown requirement. There are other options. Does that answer your question?
 
electrofelon said:
Putting the inverter near the array is one way to meet the rapid shutdown requirement. There are other options. Does that answer your question?
Click to expand...
I'm told the new inverters, solar edge, has arc fault and rapid shutdown built in. Does this inverter or a disconnect need to be within 10 feet of the roof array? Thanks
 
GerryB said:
I'm told the new inverters, solar edge, has arc fault and rapid shutdown built in. Does this inverter or a disconnect need to be within 10 feet of the roof array? Thanks
Click to expand...

If it's a recently manufactured SolarEdge, then the answers are 'No'. Older stock SolarEdge inverters require a kit to be installed.
 
The inverter does not need to be on the roof since shutting down the inverter shuts down the optimizer at each panel. (Output goes to 1V DC each and the limit per series string keeps the total down.)
But there has to be a bleeder resistor added at the inverter to discharge all of the caps fast enough. Power used during normal operation is trivial.


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GerryB said:
A friend said his engineer is quoting 690.12 for the rapid shutdown and that the inverter (with rapid shutdown) has to be on the roof, or I guess not farther then 10 feet from it. We just adopted the 2014 NEC. Is this not quite right?
Click to expand...

If your design calls for strategically locating a conventional string inverter within 10 ft of the array in order to comply with 2014 Rapid Shutdown, then you do need to locate the inverter on the roof.

This is not necessarily the case for inverters in general, as you can use DC balance of systems equipment to comply with 690.12 in liew of placing your inverter immediately adjacent to the array. For instance, a combiner box with a contactor (like those from SolarBOS) or shunt trip breaker (Midnite Solar's design) on its output. Or a unit with string-level contactors, like those available from Bentek and Innovative Solar Inc.

Like others have mentioned, SolarEdge has module-level rapid shutdown (or 2-modules-level rapid shutdown) by design. and therefore allow you to place the inverter anywhere. Each optimizer blocks the full module voltage from extending beyond the optimizer during open circuit conditions, such that the maximum voltage is 1 volt per optimizer. The latest and greatest SolarEdge inverters come standard with a bleed-down resistor to comply with the timing part of 690.12, but you can buy a retrofit kit to fit their earlier models. For inverters like the 14.4k and 33.3k, this part comes standard. For inverters like the 9k-US, it is serial number specific.
 
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Just remember to locate an AC disconnect up on the roof to comply with 690.15 if you put the inverters up there. Some have AC discos built into the inverters and some don't. Solaredge do not have AC disconnects built into their inverters.
 
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