Line Side Tap (AHJ wants to treat as a load)

[JasonC]

OK, So I have come here to try and get some help on how to persuade the mind of a higher level AHJ. Here is the skinny of the project in question. 200A service to the dwelling with a 200A disco then a 200A MLO panel in the house. I made a 150A Line side tap on the line side of the 200A disco. The AHJ now believes that I have a 350A Service in the dwelling and wants the grounding of the dwelling to be brought up to the requirements of 350A.

After searching the internet nothing really goes into detail that the solar IS NOT a load and that it should not be sized as a load. On the contrary it is a reducer to the load, but that is not for this thread. Since I am not overloading any conductors and I am not in violation of any NEC article, does anyone have any suggestions on what I can present this AHJ to show that the installation is compliant.

Thanks

 

[jaggedben]

Maybe I'm missing something, but I'm not aware that the NEC has different grounding requirements for a 350A service than for a 200A service. (There's 250.66, but that's based on conductor size, not current rating. And you haven't changed the largest conductor size). If you can offer more information about exactly what he is requiring, that might be helpful. I don't know how much ammunition we can give you if this is some local ordinance that is worded in some way that includes PV as a load.

As far as you have described the installation it sounds compliant to me. But I'm not sure what the real issue is here.

 

[shortcircuit2]

Use 250.64(D) as your guide for the grounding electrode system for the arrangement you have described.

So Jason, can you describe in detail how you made your line side connection and what type of equipment you landed the new service-entrance conductors in?

 

[JasonC]

We made taps using IPC's in the 200A CB Enclosure with 1/0 copper through an offset nipple into the 200A FSS with 150A Fuses bonded with bonding bushings. The new service disconnect is a irreversibly spliced #4 solid (GEC) to existing #4 bare solid which is bonded to the ground rod. This #4 is also bonded through the dwelling to the water and gas pipe.

What we can gather from him is that he wants us to ground for a 350A service. Which if we look at the NEC that would require a 1/0 to be ran as the ground. But he will also accept us also running an additional #4 to the water and gas lines.

 

[jaggedben]

we can gather from him is that he wants us to ground for a 350A service. Which if we look at the NEC that would require a 1/0 to be ran as the ground. But he will also accept us also running an additional #4 to the water and gas lines.

Again, what the NEC requires (table 250.66) is not based on amperage. It is based on the size of the service conductor. You have not installed a larger service conductor, as far as I can tell from your description. So there's no reason for him to require a larger GEC. I don't have the table in front of me right now, but I believe your #4 GECs are compliant for 1/0 service conductors.

If it were me, I would simply tell him I am following table 250.66, and explain that as far as I can tell it requires no more than what you installed.

 

[Zee]

Off topic, but am overwhelmed with curiousity.
150 amps of PV to a 200 A service?
I calculate 150A/125% cont. use factor= 120 Amps Inverter output.
120A at 240 Vac = 30 KW PV system?
To a dwelling.
Whoa.

I'd love to be doing 30 KW residential jobs!!

 

[shortcircuit2]

We made taps using IPC's in the 200A CB Enclosure with 1/0 copper through an offset nipple into the 200A FSS with 150A Fuses bonded with bonding bushings. The new service disconnect is a irreversibly spliced #4 solid (GEC) to existing #4 bare solid which is bonded to the ground rod. This #4 is also bonded through the dwelling to the water and gas pipe.

What we can gather from him is that he wants us to ground for a 350A service. Which if we look at the NEC that would require a 1/0 to be ran as the ground. But he will also accept us also running an additional #4 to the water and gas lines.

Jason, the inspector may be going by NOTE 1 under table 250.66

If I use table #8 in chapter 9...

4/0 = 211200
1/0 = 105600
add them = 317200 circular mil

250.66 calls for #2 copper for 317200-CM...

Or you can follow 250.64(D)(2) as he has told you he would accept. This would call for a #6 copper to the grounding electrode.

 

[jaggedben]

Jason, the inspector may be going by NOTE 1 under table 250.66

Good point.

However...

4/0 = 211200
1/0 = 105600
add them = 317200 circular mil

Not sure where you got 4/0 from. He didn't say what size the original service entrance conductors are. If they are 2/0 as permitted in 310.15(B)(7) then total kcmils are 118910, and a #4 GEC would still fit the bill.

 

[Smart $]

Jason, the inspector may be going by NOTE 1 under table 250.66...

Note 1 is regarding installations under 230.40 Exception No. 2... which says, "Where two to six service disconnecting means in separate enclosures are grouped at one location and supply separate loads from one service drop, ..." A PV system is not a load... it is an alternate power source.

 

[shortcircuit2]

jaggedben...I guessed on the 4/0 because he said 200amp service. I'd say 99% of the 200amp services on residential I've seen, have 4/0 SE conductors.

smart$...most of the specs I've seen for the inverters say they consume a small amount of power to operate which would classify it as a load...right?

Besides that, isn't the GES purpose to mitigate overvoltage and lightning imposed on the electrical system? I don't think the inspectors interpretation is out of line.

Jason, have you asked for a code section from the inspector?

 

[JasonC]

The inspector has yet to give us a formal Fail sticker referencing a code article. We have been told by him "You have a 200A service and you are adding a 150A service, you do the math." I have my NABCEP and we have done plenty of line side taps in this manner, in this county and even with this same inspector. I really am looking for something to present to him showing that this should not be treated as a load. If that were the case we would have to of had the utility give us a heavy up, and the IPC connection then would be in violation of the code. This is a case I believe that the inspector has it in his head that the scenario is wrong in his eyes, and does not want to admit he is wrong.

 

[Smart $]

smart$...most of the specs I've seen for the inverters say they consume a small amount of power to operate which would classify it as a load...right?

I claim ignorance ...


...but otherwise, let's discuss the issue of 230.82 Equipment [permitted to be] Connected to the Supply Side of Service Disconnect...
(6) Solar photovoltaic systems, fuel cell systems, or interconnected electric power production sources.

What's the point of the preceding if a PV system is always be connected through a disconnecting means and considered a load?

 

[shortcircuit2]

I claim ignorance ...


...but otherwise, let's discuss the issue of 230.82 Equipment [permitted to be] Connected to the Supply Side of Service Disconnect...
(6) Solar photovoltaic systems, fuel cell systems, or interconnected electric power production sources.

What's the point of the preceding if a PV system is always be connected through a disconnecting means and considered a load?

Ooooo...now you want to look at this from a different angle.

Hmmm...(6) Solar photovoltaic systems, fuel cell systems, or interconnected electric power production sources. Pretty vague code description IMO. And how is the electrician supposed to make this connection...with alligator clips?

I think (6) should give more direction on how this is to be done such as...


(6)Solar photovoltaic systems, fuel cell systems, small wind electric systems, or interconnected power production systems, if provided with service equipment and installed in accordance with the requirements for service-entrance conductors.

I think some change is needed to better clarify how line side connections are to be done. Then Jason would not be in the dilemma he is facing.

shortcircuit

 

[Smart $]

Ooooo...now you want to look at this from a different angle.

...

I think some change is needed to better clarify how line side connections are to be done. Then Jason would not be in the dilemma he is facing.

I agree...:happyyes:

 

[jaggedben]

I think some change is needed to better clarify how line side connections are to be done. Then Jason would not be in the dilemma he is facing.

230.33 provides enough guidance as to how connections are to be made. In any case that is not at issue here; the inspector has not objected to how the tap was done.

Smart$ is correct: Note 1 under table 250.66 only applies to 230.40 Exception 2. The PV system fits under exception 5.

Maybe this varies regionally, or with the type of service, but I don't recall seeing so many 200A services with 4/0 SE conductors. Mostly I seem to recall 2/0. In any case, instead of making assumptions we should just ask Jason what size the original SE conductors are, and then we will have a definitive answer.

 

[jaggedben]

The inspector has yet to give us a formal Fail sticker referencing a code article. We have been told by him "You have a 200A service and you are adding a 150A service, you do the math." ... I really am looking for something to present to him showing that this should not be treated as a load.

For it not being treated as a load, your argument is that it falls under 230.40 Exception 5, not Exception 2, and that the note under Table 250.66 only refers to exception 2. Alternatively, just do the math. You should be looking at upgrading the GEC to a #2 at most.

This is a case I believe that the inspector has it in his head that the scenario is wrong in his eyes, and does not want to admit he is wrong.

Yup.

 

[shortcircuit2]

230.33 provides enough guidance as to how connections are to be made.

230.33 does rule out the use of alligator clips

 

[shortcircuit2]

For it not being treated as a load, your argument is that it falls under 230.40 Exception 5, not Exception 2, and that the note under Table 250.66 only refers to exception 2.

What relevence does a service feeding a load have on the size of the grounding electrode conductor?

 

[shortcircuit2]

Here is what 230.40, Exception No. 2 says:

Where two to six service disconnecting means in separate enclosures
are grouped at one location and supply separate loads from one service drop or lateral,
one set of service-entrance conductors shall be permitted to supply each or several such
service equipment enclosures.

IMO this applies to Jasons installation.

IMO, Jasons new service disconnect has to be grouped. I base my view by the fact that there is only one service point.

I'm well aware that there are many conflicting arguments about grouping. Lets not argue this point in this thread.

Lets get more details from the OP on the installation.

 

[jaggedben]

What relevence does a service feeding a load have on the size of the grounding electrode conductor?

As a practical question, I don't know the answer. As a matter of code, I think that you can argue that PV is not a load and therefore doesn't fall under 230.40 Exception 2, which specifically refers to separate loads.

Here is what 230.40, Exception No. 2 says:

Where two to six service disconnecting means in separate enclosures
are grouped at one location and supply separate loads from one service drop or lateral,
one set of service-entrance conductors shall be permitted to supply each or several such
service equipment enclosures.

IMO this applies to Jasons installation.

Not if the PV isn't a load. And not if its permitted under Exception 5 instead of Exception 2.

Is this an ironclad argument? Maybe not, especially if the inverter has a nighttime standby load. (It may or may not). But it's got a valid logic to it, and is the best argument to use with this AHJ.

IMO, Jasons new service disconnect has to be grouped. I base my view by the fact that there is only one service point.
I'm well aware that there are many conflicting arguments about grouping. Lets not argue this point in this thread.

I think grouping is irrelevant to the OP's question. Happy to agree not to argue about it.

Lets get more details from the OP on the installation.

I think the only detail we need is the size of the original service entrance conductors.