Line Side Tap?

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shortcircuit2

Senior Member
Location
South of Bawstin
In an installation with a line side tap ahead of the service disconnecting means for a building to connect a Solar PV System, would you consider the new disconnect for the solar another service to the building or a additional disconnect to the existing service to the building?
 

Smart $

Esteemed Member
Location
Ohio
In an installation with a line side tap ahead of the service disconnecting means for a building to connect a Solar PV System, would you consider the new disconnect for the solar another service to the building or a additional disconnect to the existing service to the building?
Neither...???
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
I would consider it an additional service disconnecting means for the existing service.

One could also contract with the utility for an additional service, but that's a whole different ball of wax from a "line side tap."
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
It must be one or the other to determine proper location, grouping and the 6-switch rule?

Confusing to say the least.

Hope it is clearer in the 2014 NEC.

Not really, yes, and yes.

The way you asked the question, it's a service disconnecting means, but that doesn't really answer those other questions.

The PV can be connected to a separate service as permitted in 230.2(A)(5). But usually it's connected to the existing service.

The PV can be given its own set of service entrance conductors as permitted in 230.40 Exception 5. Or it can be connected to the existing service entrance conductors.

Each set of service conductors is permitted to have up to six handles.

So it depends on how you connect.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
If I am, please cite a reference to the correct sections...

There is no section of code that I know of that exempts the PV AC disconnecting from being grouped with other service disconnecting means if that is what it is.

As far as not being service rated, I'm sure you have in mind 690.14(A). In my opinion 690.14 applies only to DC disconnects except where it explicitly refers to AC disconnects. My reasoning is this:

  • the beginning of 690.14 refers to 'photovoltaic disconnecting means'
  • the definitions relating to 'photovoltaic' in 690 generally refer to direct current power
  • In stand alone systems or systems with DC utilization equipment, an AC disconnect wouldn't necessarily disconnect the system
  • the AC side of things is handled by article 705.
  • the code doesn't use the word "photovoltaic" when referring to AC disconnects (for example in 690.14(D))
(I'm using the 2011 code as the reference here.)

I'll grant it's not totally clear if the entirety of 690.14 applies to DC discos, AC discos, or both. In my opinion 690.14 needs to be cleaned up to make clear which provisions apply to which type of discos. But to bring this back to the point at hand, it is surely a stretch to suggest that the CMP intended for 690.14(A) to supersede all of article 230.
 

shortcircuit2

Senior Member
Location
South of Bawstin
Here is a quote from the article in the link SolarPro gave me in post #3...

"It is evident that the connection of a utility-interactive PV inverter to the supply-side of a service disconnect is essentially connecting a second service-entrance disconnect to the existing service and many, if not all, of the rules for service-entrance equipment must be followed. Many years ago, the National Fire Protection Association (NFPA) made an informal interpretation that these supply-side taps were essentially a second service entrance on the building or structure and should be treated as such."

So if it is considered a second service and it connnects Solar PV as allowed in 230.2(A)(5) then the disco's can be remote for each service?

Seems like a gray area open to interpretation.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
Here is a quote from the article in the link SolarPro gave me in post #3...

"It is evident that the connection of a utility-interactive PV inverter to the supply-side of a service disconnect is essentially connecting a second service-entrance disconnect to the existing service and many, if not all, of the rules for service-entrance equipment must be followed. Many years ago, the National Fire Protection Association (NFPA) made an informal interpretation that these supply-side taps were essentially a second service entrance on the building or structure and should be treated as such."

So if it is considered a second service and it connnects Solar PV as allowed in 230.2(A)(5) then the disco's can be remote for each service?

A service and a service entrance are not the same thing. Take a look at the definitions in article 100 and compare the difference between 230.2 and 230.40.

If you do a true tap and create a new set of service entrance conductors then yes, the discos can be remote from the others. Not all supply-side connections will necessarily do this (for example, adding a PV breaker to panel where all breakers are service disconnecting means).
 

shortcircuit2

Senior Member
Location
South of Bawstin
Not really, yes, and yes.

The way you asked the question, it's a service disconnecting means, but that doesn't really answer those other questions.

The PV can be connected to a separate service as permitted in 230.2(A)(5). But usually it's connected to the existing service.

The PV can be given its own set of service entrance conductors as permitted in 230.40 Exception 5. Or it can be connected to the existing service entrance conductors.

Each set of service conductors is permitted to have up to six handles.

So it depends on how you connect.

The tap would be made ahead of the main disconnect into the existing service entrance conductors...then land in a new disconnect.

Milbank makes a lug kit to tap in the meter housing. Lets put the new disconnect outside next to the meter. But the existing disconnect is inside the dwelling.

This would be allowed under 230-40 ex #5?
 

shortcircuit2

Senior Member
Location
South of Bawstin
A service and a service entrance are not the same thing. Take a look at the definitions in article 100 and compare the difference between 230.2 and 230.40.

If you do a true tap and create a new set of service entrance conductors then yes, the discos can be remote from the others. Not all supply-side connections will necessarily do this (for example, adding a PV breaker to panel where all breakers are service disconnecting means).

Ok...I didn't think of this scenario. In your example, the PV connection would be limited to the capacity of the service and there would have to be room for the additional breaker without exceeeding 6.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
Milbank makes a lug kit to tap in the meter housing. Lets put the new disconnect outside next to the meter. But the existing disconnect is inside the dwelling.

This would be allowed under 230-40 ex #5?

Yup, that should be allowed.

Ok...I didn't think of this scenario. In your example, the PV connection would be limited to the capacity of the service and there would have to be room for the additional breaker without exceeeding 6.

Yes. (The PV connection is always limited to the capacity of the service. That means total PV (and wind, etc) if there are multiple systems. This was made explicit in the 2011 code.)
 

Smart $

Esteemed Member
Location
Ohio
There is no section of code that I know of that exempts the PV AC disconnecting from being grouped with other service disconnecting means if that is what it is.

...
I am not in disagreement how you believe it should be done.

However, it presents a paradox. If you're permitted to tap ahead of the service disconnecting means, and the tap conductors establish a new set of service-entrance conductors, the PV system disconnecting means is then a service disconnecting means... which you then no longer have taps ahead of the service disconnecting means...???


...

"... Many years ago, the National Fire Protection Association (NFPA) made an informal interpretation that these supply-side taps were essentially a second service entrance on the building or structure and should be treated as such."

Seems like a gray area open to interpretation.
Exactly. An informal interpretation isn't binding.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
I am not in disagreement how you believe it should be done.

However, it presents a paradox. If you're permitted to tap ahead of the service disconnecting means, and the tap conductors establish a new set of service-entrance conductors, the PV system disconnecting means is then a service disconnecting means... which you then no longer have taps ahead of the service disconnecting means...???

Not totally sure what you're getting at, although you wouldn't be the first person to point out that the applicability of 230 is implied by the code rather than explicitly stated.

Perhaps if the word 'existing' were added to 705.12(A) it would remove the 'paradox' you're talking about. I think it's mostly a semantic argument and the intent of the code is seriously in doubt. It's hard to read 230 in a way that it doesn't apply to the interconnected power sources it specifically refers to. For example 230.71(A) reads: "The service disconnecting means for each service permitted by 230.2, or for each set of service-entrance conductors permitted by 230.40 Exception No. 1,3,4,5 ..." Hard to read that and say that the what the code refers to as "service disconnecting means" don't have to follow the rules for service disconnecting means. 230.71 also specifically calls out which equipment shall not be considered service disconnecting means, and power production sources are not included.
 

shortcircuit2

Senior Member
Location
South of Bawstin
There is an article in the Dec/Jan 2013 SolarPro magazine on pg. 14 by Marvin about this issue. I see it as best to discuss with the AHJ until the NEC is more specific.

Good information guys. Thanks for the feedback.
 

Smart $

Esteemed Member
Location
Ohio
Not totally sure what you're getting at, although you wouldn't be the first person to point out that the applicability of 230 is implied by the code rather than explicitly stated.
I am not saying the applicability of 230 is implied. I'm saying it is overridden.

90.3 Code Arrangement. ... Chapters 5, 6, and
7 apply to special occupancies, special equipment, or other
special conditions. These latter chapters supplement or modify
the general rules. Chapters 1 through 4 apply except as
amended by Chapters 5, 6, and 7 for the particular conditions.
...

690.3 Other Articles. Wherever the requirements of other
articles of this Code and Article 690 differ, the requirements
of Article 690 shall apply and, if the system is operated in
parallel with a primary source(s) of electricity, the requirements
in 705.14, 705.16, 705.32, and 705.143 shall apply.

690.15 Disconnection of Photovoltaic Equipment. Means
shall be provided to disconnect equipment, such as inverters,
batteries, charge controllers, and the like, from all ungrounded
conductors of all sources. If the equipment is
energized from more than one source,
the disconnecting
means shall be grouped and identified.

A single disconnecting means in accordance with 690.17
shall be permitted for the combined ac output of one or more
inverters or ac modules in an interactive system.


Perhaps if the word 'existing' were added to 705.12(A) it would remove the 'paradox' you're talking about. I think it's mostly a semantic argument and the intent of the code is seriously in doubt. It's hard to read 230 in a way that it doesn't apply to the interconnected power sources it specifically refers to. For example 230.71(A) reads: "The service disconnecting means for each service permitted by 230.2, or for each set of service-entrance conductors permitted by 230.40 Exception No. 1,3,4,5 ..." Hard to read that and say that the what the code refers to as "service disconnecting means" don't have to follow the rules for service disconnecting means. 230.71 also specifically calls out which equipment shall not be considered service disconnecting means, and power production sources are not included.
The equipment called out as not considered service disconnecting means only applies to that section, and 230.71(A) does not mention 230.40 Exception No. 6.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
I am not saying the applicability of 230 is implied. I'm saying it is overridden.

We might have to agree to disagree.

90.3 and 690.3 are only relevant if there is something in those articles that clearly contradicts some part of 230. Whether 690.14(A) contradicts anything in 230 is what we are debating, I think. My opinion is still that it does not apply to anything that is addressed in 230, because it does not apply to AC disconnects. Even if it did apply to AC disconnects, that would only mean that AC disconnects for PV systems would not be required to be service rated. It would not change any of the grouping or handle-limit requirements.

690.15 is a separate section from 690.14, and is therefore not relevant to the meaning of 690.14 in my opinion. Moreover that section applies to all PV systems whether connected to the grid or not, which is I think the main reason it is in there.

The equipment called out as not considered service disconnecting means only applies to that section, and 230.71(A) does not mention 230.40 Exception No. 6.

There is no Exception No. 6 to 230.40. PV systems are covered by 230.40 Exception No. 5. I think you are confusing 230.40 with 230.82.
 
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