connecting EGC and neutral for a line side tap (supply side connection)

Smart $

Esteemed Member
Location
Ohio
Um, 230.70, General? Definition of service entrance conductors?

(I'm pretty sure that last time around you ended up arguing that they are not SECs because of the definition of a service. [EDIT: actually it appears you never really responded to my points on this.] )
Are you saying it is a service?

That is at best up for debate.
There are all kinds of paradoxical issues involved, and jaggedben knows it... which I believe is why I didn't "respond" in that other thread.

Ultimately you could say none of the conductors or equipment solely for the PV system are part of a service because...
Service. The conductors and equipment for delivering electric
energy from the serving utility to the wiring system of
the premises served.
The purpose of the conductors and equipment is to deliver electric energy from the PV system. All the other arguments are rendered moot by this one definition.
 
The purpose of the conductors and equipment is to deliver electric energy from the PV system. All the other arguments are rendered moot by this one definition.
I think that is a lame argument. Sorry. Clearly it's just an out dated definition that needs some revision. A service doesn't cease being a service everytime pv production exceeds usage.
 

jaggedben

Senior Member
Are you saying it is a service?

That is at best up for debate.
I was only saying, in that post, that it's not valid to argue that the PV disconnect is not a service disconnect but the conductors to it may be service entrance conductors. One thing the code is clear on is that service entrance conductors terminate at service equipment and a service disconnecting means.

I've thought about writing a summary of code sections 'for' and 'against'. Maybe it's time to do that.
 

jaggedben

Senior Member
I think that is a lame argument. Sorry. Clearly it's just an out dated definition that needs some revision. A service doesn't cease being a service everytime pv production exceeds usage.
I came so close to submitting a proposal for a changed definition last time around. What gave me pause is that I think it's actually to PV installers advantage to have it vauge, if we are familiar with the arguments and can plan accordingly.
 

Smart $

Esteemed Member
Location
Ohio
I think that is a lame argument. Sorry. Clearly it's just an out dated definition that needs some revision. A service doesn't cease being a service everytime pv production exceeds usage.
Anything I throw out there is going to be weak. We've already amassed enough rhetoric on the matter to prove that. :happyyes:

Perhaps the definition is outdated, but I think we rely too much on definitions. Definitions work great for general usage. We may have to stretch the specifics just a tad for cases on the fringe. Some are too permissive, others too restrictive. We could probably have a separate code just for writing and implementing definitions.

Leaving definitions out of the debate, here's the crux of it. 230.82(6) permits PV to be connected to the supply side of the service disconnecting means. 230.40 Exception No. 5 permits an extra set of service entrance conductors to supply a PV system. 230.70 says we need a service disconnecting means at the end of service entrance conductor. The paradox is, if the disconnect is a service disconnecting means, then 230.82(6) or 230.40 Exception No. 5 are superfluous as you could never have a PV system connected to the supply side of a service disconnect. That in turn makes 705.12(A) an extension of the paradox.

So what do we do? We say the disconnect is not a service disconnecting means and we can at least make a supply-side connection. :angel:
 

jaggedben

Senior Member
I've thought about writing a summary of code sections 'for' and 'against'. Maybe it's time to do that.
Okay here you go, have fun. :D I believe this is fairly exhaustive but feel free to point out anything I've missed.

Is a PV disconnect for a supply side connection a service disconnecting means? Code sections that imply 'yes' or 'no.'

'Yes'

  • Article 100 definitions of 'Service Conductors', 'Service Entrance Conductors' and 'Service Point.' Along with the requirements of 230.70, these logically entail that the conductors require what 230.70 calls 'a service disconnecting means'. Note that the definition of 'Service Point' is not negated even if the definition of 'Service' is not considered to apply. One would have to argue that the installation has no 'Service Point' to avoid the requirements of 230.70.
  • 230.2(A)(2) - allows an additional service for parallel power production systems. This code section calls this connection a service, even though that's not consistent with the article 100 definition for 'Service'.
  • 230.40 Exception 5 - Refers (via reference to 230.82(6)) to the PV system using 'service entrance conductors', which along with 230.70 requires a service disconnecting means. Also uses the phrase 'supply side of the normal service disconnecting means', (emphasis added), which avoids the implication that all the service disconnecting means must be elsewhere, as opposed to just the 'normal' ones. (see below)
  • 230.70 Titled 'Service Equipment Disconnecting Means,' it requires service entrance conductors to have a disconnecting means. It refers to this means with the phrase 'service disconnecting means' six times, as well as the phrase 'service disconnect' twice. Any installation with a 'Service Point' ends up having to meet these requirements. Any invocation of 230.40 Exception 5 to justify a supply side tap would also invoke 230.70. Notably, the Article 100 definition of 'Service Equipment' is not actually necessary for invoking the requirements of this section.
  • 230.71 Note that nothing that can reasonably construed as applying to a PV system is included in 230.71(A)(1) thru (4).


'No'

  • Article 100 Definition of a Service, which refers to 'delivering energy from the serving utility to the wiring system of the premises served.' (However this definition is not really invoked in any requirements.)
  • Article 100 Definition of Service Equipment, which refers to 'load end of service conductors'. (However this definition is not really invoked in any requirements.)
  • 230.82 and 705.12(A), 705.31: These sections use the phrase 'supply side of the service disconnecting means', which can be taken to imply that the service disconnecting means are elsewhere. (Note again that 230.40 Exception 5 avoids this implication with the additional of the word 'normal'.)
  • 230.82(6): Notably this section does not include the same restrictions as 230.82(5).


All references are 2014 NEC. I believe the 2017 NEC will exacerbate the problem with new language in the 690 Rapid Shutdown requirements.
 

Smart $

Esteemed Member
Location
Ohio
Most inverters have some power consumption...and the Data Acquisition Systems consume power also...all powered by the serving utility's Service to the premises.
When the PV system is producing power, there is no consumption of utility provided power. Your statement, however, is 100% accurate when the PV system has less than zero net production.
 
..... The paradox is, if the disconnect is a service disconnecting means, then 230.82(6) or 230.40 Exception No. 5 are superfluous as you could never have a PV system connected to the supply side of a service disconnect. That in turn makes 705.12(A) an extension of the paradox.
I agree, and that is partly why I think they should ditch the silly "supply side" concept: it really is just adding another set of SEC so add that to the list of exceptions for multiple sets, and addition exceptions for number of disconnects and grouping.
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
I think that is a lame argument. Sorry. Clearly it's just an out dated definition that needs some revision. A service doesn't cease being a service everytime pv production exceeds usage.
But a line side interconnection is never a load in the absence of a fault. Yeah, I know it pulls a few Watts at night, but that is inconsequential relative to the size of the connection.

I'm not saying (again) that it is definitively one way or the other, only that it is subject to interpretation. Personally, I believe that either way it is interpreted a PV system can be safely designed and installed. For me it just comes down to the way the AHJ prefers it. I have many systems in place on both sides of the issue and I don't lose sleep over any of them.
 

iwire

Moderator
Staff member
Location
Massachusetts
I think that is a lame argument. Sorry. Clearly it's just an out dated definition that needs some revision. .
I strongly disagree and are you aware the present definition is only a few code cycles old as it is?


A service doesn't cease being a service everytime pv production exceeds usage
That is very debatable, but lets put that aside.

In my opinion a service disconnect stops being a service disconnect when it does not disconnect utility power to the building or structure.


I see them making a new term, perhaps co-generation disconnecting means, but I really believe they will reserve service disconnecting means to the use that is has always been.
 

iwire

Moderator
Staff member
Location
Massachusetts
but I still say it's a bad definition.
I am pretty clear on that part. :)

So say I am installing a "PV only service", then I just ignore article 230?
Sure. :cool:



Kidding, that is a good question.:cool:


A simple section in 705 to install a co-generation disconnecting means per article 230. etc. could solve that.


In my view the difference between our approaches is that you want the general code to bend / change for PV while my position is PV needs to make its own rules to follow in 690 / 705.

Why make the people not doing these installs learn new terms for things that they already understand?
 

pv_n00b

Senior Member
Location
CA, USA
Assuming the AHJ does not specify, what does an installer have to lose by making the PV disconnect on a supply side interconnection a service entrance? It's the difference between putting in a system bond or not. While it's interesting to argue for it being a service entrance or not I'm not sure what people hope to gain by not installing it as a service entrance. Educate me on this point please.
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
Assuming the AHJ does not specify, what does an installer have to lose by making the PV disconnect on a supply side interconnection a service entrance? It's the difference between putting in a system bond or not. While it's interesting to argue for it being a service entrance or not I'm not sure what people hope to gain by not installing it as a service entrance. Educate me on this point please.
In my case, I really don't care all that much. It's a bit simpler/cheaper just to run the EGC back to the service rather than establishing a new GEC on the other side of the split and bonding it to the existing electrode, but it's not a big deal. A case for compliance can be made either way.

That said, however, in the cases of San Antonio and Austin, both AHJ's have explicitly stated how they want it done, and they disagree.
 

jaggedben

Senior Member
I strongly disagree and are you aware the present definition is only a few code cycles old as it is?
In my opinion a service disconnect stops being a service disconnect when it does not disconnect utility power to the building or structure.
An exporting PV system doesn't stop utility power from being connected to the building. If the definition said 'power' instead of 'energy' then there would be no debate.

Also you realize that from a person's point of view, first responder or electrician or whoever, it makes no difference, right?
 

c_picard

Senior Member
Location
USA
A simple section in 705 to install a co-generation disconnecting means per article 230. etc. could solve that.
There was a proposal for that very language back in the 2014 cycle. It was unanimously rejected, with the reasoning that it was already covered and the language wasn't necessary. They basically said "Duh, everyone already knows to look in 230". No one needs to learn anything new, just keep doing what we've been doing all along...disconnecting service entrance conductors with service-rated disconnects.
 

jaggedben

Senior Member
Why make the people not doing these installs learn new terms for things that they already understand?
Why not just redefine the terms to accurately reflect what people actually use those terms to describe?

Changing the definition of service to "delivering energy between the serving utility to the wiring system of the premises served" wouldn't require anybody 'not doing these installs' to learn new terms or change the way they've been using them.
 
Top