Inverter working clearance

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electro7

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Northern CA, US
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Electrician, Solar and Electrical Contractor
I am wondering about inverter clearance in the picture attached. The ledge protrudes out 16.5". The inverter depth is 13.5". Do you think its okay for me to mount the inverter straight to the back wall? Or do you think I need to build it out with strut so that the face of the inverter is at least flush with the ledge?

I am hoping it woukd be okay to mount directly against the wall to avoid extra costs building with strut. The AC breakers for the inverters are in a panelboard directly to the right of the inverters within site of and only 5ft away. Not sure if that would make a difference in the decision.
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I can't imagine that a reasonably-minded inspector would have a problem with the ledge extending 3" past the front of the inverters, but "reasonably-minded" is the operative phrase. Are you sure that the top inverter is low enough, though?
 
Well Im not concerned with height since the breakers operating each inverter are in the panelboard right next to the inverters at ground level.

Thanks ggunn for the input

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I agree with ggunn. In my experience about 95% of inspectors would not make an issue of the ledge but then there's that one-out-of-20 who will, and I've experienced that.

As far as the inverter height it's fine if you don't have any switches in the inverter. But if you have a DC switch there, then that switch is not readily accessible, and you will have consider whether you'd need an additional readily accessible DC disconnect. The current code is a little vague about whether the DC switch counts as "a" PV System Disconnecting Means subject to 690.13(A), or whether the AC breaker can be "the" PV system disconnecting means that meets that requirement. Probably not an issue unless you get the same one-out-of-20 inspector.
 
K thanks for the input. I think I have a good argument for the height issue since the inverters are protected by Tigo rapid shutdown optimizers. The ac breaker opened would bring the dc voltage down to the safe limit.

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electro7 said:
K thanks for the input. I think I have a good argument for the height issue since the inverters are protected by Tigo rapid shutdown optimizers. The ac breaker opened would bring the dc voltage down to the safe limit.

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I think the height issue comes down to whether there are switches or displays that need to be accessed from the ground. A breaker on the AC side, for example, cannot take the place of a DC disconnect.
 
petersonra said:
I don't see anything in 690 that says you don't have to comply with 110.26(A).
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Right, so the question is whether inverters are considered equipment "likely to require examination, adjustment, servicing, or maintenance while energized." Which is a judgement call, and hence information about how AHJs are making that judgement is on point.

Cheers, Wayne
 
wwhitney said:
Right, so the question is whether inverters are considered equipment "likely to require examination, adjustment, servicing, or maintenance while energized." Which is a judgement call, and hence information about how AHJs are making that judgement is on point.

Cheers, Wayne
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It is not a judgement call. How would you ever debug or troubleshoot such a thing without making voltage measurements while it was live. You can claim it otherwise, and maybe get the inspector to agree, but the reality is that it WILL require at some point that you make voltage tests on it while it is on.

Do you check the voltages after you wire everything up?
 
So what's your objective definition of "likely"? What probability over what period of time? And how do we determine that probability ahead of time?

Cheers, Wayne
 
wwhitney said:
So what's your objective definition of "likely"? What probability over what period of time? And how do we determine that probability ahead of time?

Cheers, Wayne
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The code does not make any reference at all to how often it would need to be accessed while live. The fact is that over the lifetime of the equipment the certainty of having to examine it while live is close to 100%.

I am not saying you can't get an inspector to let you get away with it, but as far as the actual wording of the code, there is not much in the way of wiggle room.
 
What about carports? All over California and at a school district I just did the Core 1 inverters were mounted to the column approximately 12ft high. The engineer required an ac disconnect at working height (middle of switch no greater than 79"), but the inverters with ac and dc disconnects were high. I see it all over CA.

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petersonra said:
The code does not make any reference at all to how often it would need to be accessed while live.
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I was not referring to how often it would need to be accessed while live. If the chance you need 1 or more live accesses over the life of the product is, say, 90% or more, that's obviously "likely". But suppose the chance is 1 per 100 product-years, with a 20 year life span for the product. Is that likely? Or suppose it's 1 per 1000 product-years, is that likely? "Likely" is undefined.

electrofelon said:
At the very least, you will be checking string voltages while commissioning.
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I agree with you that if checking string voltages live while commissioning is SOP, then that equipment obviously needs to meet the 110.26(A) clearances. But my ignorance of different products comes into play here, for something like a SolarEdge 7.6kW inverter, would you typically do that or need to do that? Or would you just hook everything up, power it up, and check what the inverter tells you? Then if there's a problem, depower, adjustment connections, and repeat.

The latter, with all AC disconnects, DC disconnects, and OCPD located elsewhere, was what I had in mind for an inverter than might not require 110.26(A) clearances.

Cheers, Wayne
 
petersonra said:
I don't see anything in 690 that says you don't have to comply with 110.26(A).
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But 110.26(A)(3) permits other "other equipment or support structures such as concrete pads" located above or below the equipment to extend up to 6" beyond the front of the equipment. It looks like he's covered to me.
 
Im going back to my question of carport structures. Are all of the solar carport structures with the inverters mounted high on the columns code violations?

Maybe there is something in the CEC that allows that (I am in CA), that is different than the NEC. Does anybody know?

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Petersonra, what do you think about my earlier question about carports and heights of inverters that are mounted on columns?

Do you have solar carports in your location?

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electro7 said:
Im going back to my question of carport structures. Are all of the solar carport structures with the inverters mounted high on the columns code violations?

Maybe there is something in the CEC that allows that (I am in CA), that is different than the NEC. Does anybody know?

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The discussion about 110.26 is only about the ledge protruding beyond the face of the inverter. 110.26 does not restrict equipment height. So no, according to that section all those carports are fine.

The requirement for a readily accessible Pv system disconnect is something that those carports may be skirting, but it's not as simple as the inverter being up high is a violation.


And no, there's nothing different in CA.
 
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