AC Inverter Output Wiring

[kdearth]

I recently had my final electrical inspection. There were several minor items noted that I am addressing. However, the inspector is requiring that I run the AC Inverter Output Circuit, that routes from a roof mounted junction down into my attic and over to an accessible disconnect on the exterior of my garage wall, next to the service meter, to be in conduit. He references violation of code 690.31(E) which specifically refers to "Direct-Current PV Source and Output Circuits Inside a Building." When I pointed this out the inspector just said it was required.

I talked to another inspector who referenced 690.14(C)(1). This section of code deals with disconnect locations. It states:

"The photovoltaic disconnecting means shall be installed at a readily accessible location either on the outside of a building or structure OR inside nearest the point of entrance of the system conductors.

Exception: Installations that comply with 690.31(E) shall be permitted to have the disconnecting means located remote from the point of entry of the system conductors."

Again my AC disconnect is located on an exterior garage wall next to the service meter in a readily accessible location. I was told by the second inspector the "exception" applied due to the location of my AC disconnect. I don't understand how that is correct. My understanding is that 690.14(C)(1) establishes requirements for disconnect location (AC and DC) and the exception would apply, but only to the conductors of a DC disconnect. The inspectors refuse to budge. Anyone have any issues with this?

 

[ggunn]

I recently had my final electrical inspection. There were several minor items noted that I am addressing. However, the inspector is requiring that I run the AC Inverter Output Circuit, that routes from a roof mounted junction down into my attic and over to an accessible disconnect on the exterior of my garage wall, next to the service meter, to be in conduit. He references violation of code 690.31(E) which specifically refers to "Direct-Current PV Source and Output Circuits Inside a Building." When I pointed this out the inspector just said it was required.

I talked to another inspector who referenced 690.14(C)(1). This section of code deals with disconnect locations. It states:

"The photovoltaic disconnecting means shall be installed at a readily accessible location either on the outside of a building or structure OR inside nearest the point of entrance of the system conductors.

Exception: Installations that comply with 690.31(E) shall be permitted to have the disconnecting means located remote from the point of entry of the system conductors."

Again my AC disconnect is located on an exterior garage wall next to the service meter in a readily accessible location. I was told by the second inspector the "exception" applied due to the location of my AC disconnect. I don't understand how that is correct. My understanding is that 690.14(C)(1) establishes requirements for disconnect location (AC and DC) and the exception would apply, but only to the conductors of a DC disconnect. The inspectors refuse to budge. Anyone have any issues with this?

Is your system a microinverter system? If so, does your inspector realize that these are AC (not DC) conductors? That section of the code is for protection of DC conductors with their attendant risk of arcs. AC wiring from inverters is like any other AC wiring inside a house.

Unfortunately, however, the AHJ's inspectors are the last word, even when they are wrong.

 

[jaggedben]

Instead of arguing that 690.31(E) doesn't apply, try arguing that you've complied with it and therefore met the exception in 690.14(C).

In other words, to spell it out:

1) Your DC conductors terminate on the roof.
2) Therefore your system complies with 690.31(E)!
3) Therefore the exception to 690.14(C)(1) applies, and your AC disconnecting means can be remote from the point of entry.
4) (Mention that you've talked to other installers who have done what you've done in other jurisdictions and many AHJs have no problem with it.)
5) (Point out that the wiring is electrically no different whatsoever from any other AC mutli-wire branch circuit which you are allowed to run the way you have.)

If that doesn't work nothing will. Unfortunately 690.14 is pretty vague. In my opinion it needs to be revised to make clear which portions apply to DC and/or AC disconnecting means.

Also, the code really does not know micro-inverters from nothin'. It was just not written to address your situation and that's part of the problem.

 

[kdearth]

Thanks for the reply fellas. I have pointed out on multiple occassions, more than I can count, that the inverter output circuits are AC and not DC. I have come to the conclusion that the first inspector is clueless and extremely disgruntled. And the second inspector I spoke with (the 1st inspectors boss) is just plain stubborn. He will acknowledge that 690.31 refers to DC conduits but then tries to say it applies to AC also. He just seemed to keep talking in circles. I pretty much have them both upset with me. I know the second inspector knows he is wrong, he has all but admitted it, but in order to "save face" I guess he wont outright admit it.


I emailed Mike Holt directly on the issue and his response was that I am right and the inspectors are wrong. I forwarded the email from him onto the chief inspector. I am sure that will ruffle some feathers. Hopefully it will at least get them thinking that maybe there is some illegitimacy to their way of thinking.


I could just "give in" but I don't believe in doing that. In an industry that tends to struggle and me trying to establish a solar installation business down the road at some point, knowing the NEC and applying the NEC is paramount. I don't want to have to worry that different AHJs or even the same AHJ is going to have their own stipulations outside of the NEC. It's an unecessary worry, expense, and time consuming.

 

[jxofaltrds]

Thanks for the reply fellas. I have pointed out on multiple occassions, more than I can count, that the inverter output circuits are AC and not DC. I have come to the conclusion that the first inspector is clueless and extremely disgruntled. And the second inspector I spoke with (the 1st inspectors boss) is just plain stubborn. He will acknowledge that 690.31 refers to DC conduits but then tries to say it applies to AC also. He just seemed to keep talking in circles. I pretty much have them both upset with me. I know the second inspector knows he is wrong, he has all but admitted it, but in order to "save face" I guess he wont outright admit it.


I emailed Mike Holt directly on the issue and his response was that I am right and the inspectors are wrong. I forwarded the email from him onto the chief inspector. I am sure that will ruffle some feathers. Hopefully it will at least get them thinking that maybe there is some illegitimacy to their way of thinking.


I could just "give in" but I don't believe in doing that. In an industry that tends to struggle and me trying to establish a solar installation business down the road at some point, knowing the NEC and applying the NEC is paramount. I don't want to have to worry that different AHJs or even the same AHJ is going to have their own stipulations outside of the NEC. It's an unecessary worry, expense, and time consuming.

Good for you. Are you an IAEI member? If not join. In central Ohio we meet in Westerville, inspectors and contractors. We are hosting the state meeting next year in Dublin. ---- (Ohio) don't want the thread to get off topic!

 

[ggunn]

Thanks for the reply fellas. I have pointed out on multiple occassions, more than I can count, that the inverter output circuits are AC and not DC. I have come to the conclusion that the first inspector is clueless and extremely disgruntled. And the second inspector I spoke with (the 1st inspectors boss) is just plain stubborn. He will acknowledge that 690.31 refers to DC conduits but then tries to say it applies to AC also. He just seemed to keep talking in circles. I pretty much have them both upset with me. I know the second inspector knows he is wrong, he has all but admitted it, but in order to "save face" I guess he wont outright admit it.

I emailed Mike Holt directly on the issue and his response was that I am right and the inspectors are wrong. I forwarded the email from him onto the chief inspector. I am sure that will ruffle some feathers. Hopefully it will at least get them thinking that maybe there is some illegitimacy to their way of thinking.

There's no winning this fight, IMO. If you win the battle and down the road you lock horns with these guys again, they probably will remember this and be... difficult. I completely agree with your interpretation of the Code, for what that's worth, and in a more ideal world the inspectors would be open to learning how to correctly handle new situations, but bureaucrats being what they generally are (in positions of power and, at their worst, unemployable in the private sector) you may have a Sisyphusian task on your hands trying to educate them. To some folks it's better to be right than to be correct.

Good luck with that windmill, Mr. Quixote.

 

[sgunsel]

Our utility requires a PV disconnect to be identified as such and located outside at the service entrance. They don't like the AC being on when they think it is off.

 

[kdearth]

I had a bit of a breakthough, but not really. The chief inspector emailed me back with a lengthy repsonse. He has mostly stayed out of the fray and kept passing me off to the inspectors up until now. He did acknowledge that using 690.31(E) is not viable due to it specific reference to DC conductors. This is in stark contrast to what the two inspectors I spoke with were trying to claim.

"I can see an inspector (using 90.4 "alternative methods") permitting the location of the disconnecting means per the Exception to 690.14(C)(1) if the AC cables were installed within the rigid framework of the rules of 690.31(E) but I personally would not "go there" as an inspector. I agree with you, the Exception is for DC conductors not AC"


However, he still implies that the AC inverter output conductors must be in conduit......

"NEC 690.14(D)(3) reinforces (by referencing 690.14(C)(1)) that there shall be a disconnecting means installed at a readily accessible location either on the outside of a building or inside nearest the point of entrance of the system conductors. The choice of "either on the outside of a building or inside nearest the point of entrance" doesn't mean that one can run the system conductors directly THROUGH a building to some remote location to an outside disconnect. Rather, in layman's terms, it means the disconnecting means can be located outside before the conductors enter the building or located inside as soon as they enter the building. And for what it's worth, this wording is not new or unique to PV installations. Rather it is a basic wiring practice going back to the infancy of the electrical industry. When you have system conductors - be they service entrance; or feeders to a remote building; or in this case PV conductors, you have to have (for safety) a disconnecting means properly located and it has to be located as outlined above.

Now that said, the Exception to 690.14(C)(1) is not a mandatory rule, instead it is a "shall be permitted" rule meaning "You can do it this way if you want to" (if it's DC). This particular rule says in effect, the disconnecting means doesn't have to be located outside before the conductors enter the building or inside as soon as they enter the building IF it is DC and it is in metal. (690.31(E)). But as you said, your conductors aren't DC so that rule (the exception) doesn't apply to this installation."


This is the part I don't agree with:
"doesn't mean that one can run the system conductors directly THROUGH a building to some remote location to an outside disconnect. "

What exactly prevents me from doing this? The code strictly specifies that if they are DC conductors then this is allowed so long as they are on conduit per 690.31(E). But nothing about AC conductors. There is no need for them to be in conduit. It's just branch circuit wiring, same as wiring a light bulb in your attic.​

 

[kdearth]

I feel as though I should clarify, if I haven't done so, I am not able to install the AC disconnect on the roof or in the attic where the conductors penetrate the roof due to it being non-accessible. The AC disconnect is located in the most readily accessible location which is on the exterior of my attached garage, and was deemed to be within code. It's not a different building. One branch circuit literally drops down into the attic over top of my garage/porch.

 

[ggunn]

Our utility requires a PV disconnect to be identified as such and located outside at the service entrance. They don't like the AC being on when they think it is off.

That's true of most AHJ's but it's not the issue here.

 

[ggunn]

I had a bit of a breakthough, but not really. The chief inspector emailed me back with a lengthy repsonse. He has mostly stayed out of the fray and kept passing me off to the inspectors up until now. He did acknowledge that using 690.31(E) is not viable due to it specific reference to DC conductors. This is in stark contrast to what the two inspectors I spoke with were trying to claim.

"I can see an inspector (using 90.4 "alternative methods") permitting the location of the disconnecting means per the Exception to 690.14(C)(1) if the AC cables were installed within the rigid framework of the rules of 690.31(E) but I personally would not "go there" as an inspector. I agree with you, the Exception is for DC conductors not AC"


However, he still implies that the AC inverter output conductors must be in conduit......

"NEC 690.14(D)(3) reinforces (by referencing 690.14(C)(1)) that there shall be a disconnecting means installed at a readily accessible location either on the outside of a building or inside nearest the point of entrance of the system conductors. The choice of "either on the outside of a building or inside nearest the point of entrance" doesn't mean that one can run the system conductors directly THROUGH a building to some remote location to an outside disconnect. Rather, in layman's terms, it means the disconnecting means can be located outside before the conductors enter the building or located inside as soon as they enter the building. And for what it's worth, this wording is not new or unique to PV installations. Rather it is a basic wiring practice going back to the infancy of the electrical industry. When you have system conductors - be they service entrance; or feeders to a remote building; or in this case PV conductors, you have to have (for safety) a disconnecting means properly located and it has to be located as outlined above.

Now that said, the Exception to 690.14(C)(1) is not a mandatory rule, instead it is a "shall be permitted" rule meaning "You can do it this way if you want to" (if it's DC). This particular rule says in effect, the disconnecting means doesn't have to be located outside before the conductors enter the building or inside as soon as they enter the building IF it is DC and it is in metal. (690.31(E)). But as you said, your conductors aren't DC so that rule (the exception) doesn't apply to this installation."


This is the part I don't agree with:
"doesn't mean that one can run the system conductors directly THROUGH a building to some remote location to an outside disconnect. "

What exactly prevents me from doing this? The code strictly specifies that if they are DC conductors then this is allowed so long as they are on conduit per 690.31(E). But nothing about AC conductors. There is no need for them to be in conduit. It's just branch circuit wiring, same as wiring a light bulb in your attic.​

If I am reading this correctly, the senior inspector says that even putting your AC conductors in conduit wouldn't make him happy. It seems to me that he is saying that the direction of current flow is important, and where the conductors enter the building is up on the roof, not down by the service. FWIW, I have heard of AHJ's requiring a disconnect on the roof if conductors are routed through a building irrespective of whether they are AC or DC. It makes no sense if they are AC, since opening the disconnecting means down by the service shuts down the inverters and de-energizes the conductors, but the AHJ has, as the name states, jurisdiction.

 

[kdearth]

GGun,

I kind of got that feeling also. It seems he thinks once we figure out placement for the disconnect then we can discuss wiring form there.

"I believe once you have the disconnecting means issue sorted, the wiring methods will fall into play without further incident."

This tells me he thinks the AC disconnect is in the wrong place. When I spoke to the second inspector he asked if I had a permanant ladder or fold down ladder for access to the roof or attic. I said no and that a ladder needed to be placed there. He informed me that makes them non-readily accessible, in which it would be against 690.14.(C)(1). That tells me the roof (next to the solar panels or the entrance for the conductors) is off limits as is the attic. Where does that leave me?

There seems to be some discontinuity between the AHJ inspectors themselves. The thing that gets me is even though they have agreed that 690.31(E) should not apply, they still refer to it as though it applies.

 

[ggunn]

GGun,

I kind of got that feeling also. It seems he thinks once we figure out placement for the disconnect then we can discuss wiring form there.

"I believe once you have the disconnecting means issue sorted, the wiring methods will fall into play without further incident."

This tells me he thinks the AC disconnect is in the wrong place. When I spoke to the second inspector he asked if I had a permanant ladder or fold down ladder for access to the roof or attic. I said no and that a ladder needed to be placed there. He informed me that makes them non-readily accessible, in which it would be against 690.14.(C)(1). That tells me the roof (next to the solar panels or the entrance for the conductors) is off limits as is the attic. Where does that leave me?

There seems to be some discontinuity between the AHJ inspectors themselves. The thing that gets me is even though they have agreed that 690.31(E) should not apply, they still refer to it as though it applies.

Another thing typical of bureaucracies is that when you are successful in going around a lower level 'crat and getting to his superior, you often open a larger can of worms. Your problem gets bigger instead of smaller and you find yourself even farther from a resolution than you were before. The name of the game is CYA and a higher level bureaucrat has a larger A to cover.

To avoid this kind of thing is one reason why I try to always run all my conduit outside the building. I realize, of course, that that's not much help to you at this point.

 

[kdearth]

Just an update. I will be meeting with the vice chief inspector at some point in the near future. I was forewarned though that he will not budge on their stance which sounds to me like "no matter how wrong I am, you must do it" sort of thing.

I was contacted today by Bill Brooks PE of Brooks Engineering. It seems as though my case is sparking the interest of some more prominant folks in the solar and NEC industry. He volunteered to discuss the matter with my AHJ. I forwarded his info to the chief inspector so we'll see what happens.

 

[jaggedben]

I was contacted today by Bill Brooks PE of Brooks Engineering. It seems as though my case is sparking the interest of some more prominant folks in the solar and NEC industry. He volunteered to discuss the matter with my AHJ. I forwarded his info to the chief inspector so we'll see what happens.

It's great that you are involving people like Bill Brooks and Mike Holt. Regardless of your outcome this time around, hopefully it will plant the seeds for a 2014 code revision that will clarify the situation. I would be interested to know what Brooks (or John Wiles) would say about whether the code-making panels intended 690.14(C) to apply to AC disconnects on inverter outputs. My guess would be that they intended it primarily to apply to DC disconnects (at least on grid tied systems) and that a carefully written revision would probably be accepted.

 

[don_resqcapt19]

... hopefully it will plant the seeds for a 2014 code revision that will clarify the situation. ...

Way too late to submit changes for the 2014 code. The ROP and draft for the 2014 has been published on the NFPA website.

 

[kdearth]

The chief inspector is unwilling to even discuss this with anyone outside of his office. That tells me that he simply doesn't want to be told he might be wrong or that he is misinterpreting the code. He explained that if it were up to him, he would remove the "exception" from 690.14(C)(1). When I tried to exlpain that I understood why it was necessary, it really upset him. He accussed me of implying he didn't know the diffeence between AC/DC circuits and that he has "30+ years of experience in the industry". Good grief it is turning into a battle of semantics now.

At this point I have exhausted all that I can. A fellow installer is now making it a point to stay out of this jurisdiction due to the difficulties I am dealing with. It's a shame.

 

[ggunn]

The chief inspector is unwilling to even discuss this with anyone outside of his office. That tells me that he simply doesn't want to be told he might be wrong or that he is misinterpreting the code. He explained that if it were up to him, he would remove the "exception" from 690.14(C)(1). When I tried to exlpain that I understood why it was necessary, it really upset him. He accussed me of implying he didn't know the diffeence between AC/DC circuits and that he has "30+ years of experience in the industry". Good grief it is turning into a battle of semantics now.

At this point I have exhausted all that I can. A fellow installer is now making it a point to stay out of this jurisdiction due to the difficulties I am dealing with. It's a shame.

That is a shame but not particularly surprising. Yours is not the only AHJ with an idiosyncratic inspector.

Can you still shove all the worms back into the can by running bit of conduit or have things escalated past the point where the situation can be that "easily" fixed?

 

[jxofaltrds]

The chief inspector is unwilling to even discuss this with anyone outside of his office. That tells me that he simply doesn't want to be told he might be wrong or that he is misinterpreting the code. He explained that if it were up to him, he would remove the "exception" from 690.14(C)(1). When I tried to exlpain that I understood why it was necessary, it really upset him. He accussed me of implying he didn't know the diffeence between AC/DC circuits and that he has "30+ years of experience in the industry". Good grief it is turning into a battle of semantics now.

At this point I have exhausted all that I can. A fellow installer is now making it a point to stay out of this jurisdiction due to the difficulties I am dealing with. It's a shame.

Guess he forgot what happened in Akron Ohio.


Beginning February 1, 2009 the City of Akron Building Inspection division will be transferred to the Summit County Department of Building Standards. The new location is 1030 E. Tallmadge Avenue, Akron, Ohio 44310. The phone number is 330-630-7280. Here is a link to their website: http://www.co.summit.oh.us/executive/bldgstds.htm
The Summit County Department of Building Standards will assume all roles of building inspection, electrical inspection, HVAC inspection, plumbing inspection, plan review, permit writing, application for building trades and all other functions previously performed by the City of Akron for projects inside the city limits.

 

[kdearth]

That is a shame but not particularly surprising. Yours is not the only AHJ with an idiosyncratic inspector.

Can you still shove all the worms back into the can by running bit of conduit or have things escalated past the point where the situation can be that "easily" fixed?

I have already acknowledged to the inspectors that I must do what they say. And I have already figured out my plan of action. I'll simply (although not so simple) bypass the attic and run wire through conduit on the exterior of my house down to the disconnect. I have two seperate junction boxes. One will be simple, the other will require a lengthy conduit run underneath about 14 panels. It will be time consuming and costly. I will probably request a different inspector since the first inspector became extremely irrate and irrational over something he later acknowledged I was correct on. This isn't a professional inspection agency, it's a circus.

As for the disagreement, the battle rages on. I am now getting emails consistently from the chief inspector. He is throwing all kinds of misc. crap my way. It seems like either a point to deflect the argument or to just to flex his "inspector muscles." I redirected the conversation and asked him exactly what code I violate and why. That is the only issue at hand to me.