Six handle rule

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Smart $ said:
I don't know about UL Standard playing any part of this, but I'd think the manufacturers of such panels would have to make unique-design breakers and panel receiver to limit panel usage to two- or three-pole breakers and no single pole. That's likely not going to happen.
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Most of the panels I've seen would take at most six single-pole. The Square-D I mentioned is the one exception I've seen.

I guess the real gist of the question is; how often, if ever, would someone run into an MLO type service panel where you actually could install a seventh handle without violating the instructions/listing? If the answer is never, then this question of whether a seventh PV handle is allowed is rather moot.
 
jaggedben said:
Most of the panels I've seen would take at most six single-pole. The Square-D I mentioned is the one exception I've seen.

I guess the real gist of the question is; how often, if ever, would someone run into an MLO type service panel where you actually could install a seventh handle without violating the instructions/listing? If the answer is never, then this question of whether a seventh PV handle is allowed is rather moot.
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On the gist...

I can't answer how often, but do you think the person that would install a seventh handle if they could (without regard for Code) is really going to adhere to a listing or instructions that say six handles max?
 
jaggedben said:
Most of the panels I've seen would take at most six single-pole. The Square-D I mentioned is the one exception I've seen.

I guess the real gist of the question is; how often, if ever, would someone run into an MLO type service panel where you actually could install a seventh handle without violating the instructions/listing? If the answer is never, then this question of whether a seventh PV handle is allowed is rather moot.
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Here's one: (BTW, I just noticed something weird about that picture. Do you see it?)
 

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GoldDigger said:
I only see six handles, so maybe not. :)
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Yeah, but then ggunn said that a seventh could be installed.

Curious if this panel has any instructions which speak to whether more than 6 breakers can be installed without having a main breaker. Obviously I'm shooting in the dark here, but the missing metal raises the issue as to how this example speaks to my question.
 
jaggedben said:
Yeah, but then ggunn said that a seventh could be installed.
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Six handles for loads, in place of a main, and one handle for PV disconnect for supply side connection.
There is no agreement on whether 7 is OK in this case or not . I would say the split on interpretation is about 50-50.
 
jaggedben said:
Missing piece of deadfront at the top?
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Look at that red handle at the top left. I didn't notice it looking at the picture small, but when the photo got bigger when I posted it, I noticed that it appears that someone took a pair of tin snips and notched out the deadfront for that breaker. Is the panel still listed?
 
jaggedben said:
Yeah, but then ggunn said that a seventh could be installed.
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A client of mine has asked me if a seventh handle could be installed in that panel. In this thread I raised the question but I did not say that it could or couldn't.
 
I'm just going to leave this here and...
hope it helps!
This is about the 2011 NEC, not sure which you are under or if anything has changed.

Question: All situations are of course unique, but...
Say for example you are putting in a PV system in a town that has *zero* ordinances about PV. So the building inspector is going by...what? State laws? If there are also *zero* state laws, he/she's going by the NEC...but are he/she really the final word?
Wouldn't the state inspector and code have precedence? But if there is no state code...wouldn't the NFPA (not sure if those letters are in the right order- I mean the folks that write the NEC) be the final word?
But...do they even make decisions like that?
Point being, if there's something unclear or contradictory in the NEC...there's no "quick fix", and the result of that is the "powers that be" might try to...avoid the issue or pretend it doesn't exist.
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One example where the lack of Code guidance can cause confusion is in determining how to apply Section 230.71(A), “Maximum Number of Disconnects,” to supply-side PV connections. Section 230.71(A), which electricians often refer to as the “sixhandle rule,” requires that the service disconnecting means contain no more than six sets of service disconnects per service. Technically, the disconnecting means for a PV system is not a service disconnect. Article 100 defines a service as “the conductors and equipment for delivering electric energy from the serving utility to the wiring system of the premises served.” Because a PV system is outside that definition, the PV disconnecting means is not governed by the six-handle rule. Section 690.14(C) (4) requires that PV system disconnecting means must have no more than six switches or six circuit breakers. Given the Code definitions and requirements, a supply-side connection could have up to six PV-specific disconnects in addition to the utility service disconnects.

This conclusion contradicts solar integrators’ traditional line of thinking, as well as information presented in the article “Can We Land?” (see June/July 2009, SolarPro magazine). My position is that a PV system disconnecting means is not a service disconnect because the inverter’s output circuit is not a utility service, and the utility service is not affected when the disconnect is in the Off position. PV system disconnects are service rated, contain overcurrent protection and must be installed in a similar fashion to service disconnects, but PV system disconnects are not service disconnects. This interpretation of the Code will likely require a conversation with your AHJ, one I suggest having before the final inspection if you feel there will be any questions or objections.
http://solarprofessional.com/articl...ec-section-70512-and-utility-interconnections
 
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This is kind of what I was getting at in my last comment- great article here.
"Interpretations" kind of make me leery when dealing with fatal voltages and potential fires.
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Since PV is still very much an emerging technology, this is an important distinction to make. For example, say a representative from a Spanish company tells me it has a 50 MW portfolio of PV projects. This may mean only that the company participated for 1 year in the Spanish PV market explosion, which was a better example of what not to do than a shining moment in the history of PV. My intent here is not to pick on the Europeans, but rather to stress that experience is relative and contextual. Experience in Germany, therefore, does not necessarily correlate directly with experience in US markets. Given that irradiance and temperature is so much lower in Germany than in California, for example, a problem may take twice as long to surface in Germany. A German company with hundreds of megawatts installed and 10 years of experience might have the equivalent of only 5 years of experience in California.

Nevertheless, the sheer magnitude of installed PV capacity in Germany represents a significant body of learning. Why is it that PV fires are not a problem in Germany, the world’s largest PV market? One reason is that the Germans generally have better wire management practices. More importantly, however, they do ground-fault detection very differently— and better.


GFP methods. The proper usages of expansion joints and segmenting disconnects are important lessons learned from the Bakersfield Fire, as are the importance of conductor-temperature calculations and improved wire management methods. However, the primary message to the codes and standards community is that we need to change the way we design and test our GFP circuits.
http://solarprofessional.com/articl...ield-fire-a-lesson-in-ground-fault-protection
 
PVfarmer said:
More importantly, however, they do ground-fault detection very differently—and better.
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If it makes you sleep better at night, the North American market has largely adopted the European method of detecting ground-faults. This is certainly true of any ungrounded PV systems, which are deployed using non-isolated (aka transformerless) inverters. Further, NEC 2014 addresses the ground-fault detection blind spot in some transformer-based inverters by requiring that ground fault ptotection devices or systems are capable of detecting faults to ground in intentionally grounded conductors.
 
djd

djd

Smart $ said:
MH graphic shows 7 disconnects with a wireway above them. Assuming there is one large set of service entrance conductors (SEC) running though the wireway, then tapped to supply each disconnect, so you have a multi-enclosure scenario under 230.40 Exception No. 2. However, the tap to the PV disconnect falls under 230.40 Exception No. 5. From there, refer to 230.71(A).

NOTE: I do not agree with the MH graphic in that I believe there has to be at least a little more space between the 6th service disconnect and the PV disconnect to set the service grouping apart.

With this explanation, can you now see how 7 handles in an MLO panel is a violation?
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why is the 6 handle rule code ? really I dont see a problem with the solar disconect than possible overload
 
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