705.12(A)

[msi99]

705.12(A) states that each source interconnection of one or more power sources installed in one system shall be made a dedicated circuit breaker or fusible disconnect means.
Does it mean if I have a solar system installed in the past and if I am looking to add another solar system with a separate inverter, both systems need to be combined since technically it's one type of source ( solar), or am I allowed to have a dedicated breaker in the MSP for each system as long as the 120% rule is satisfied. ?
The confusion here is the word "Each source" When they say each source, does it mean solar is " a source" ?

 

[jaggedben]

In my opinion, you can have multiple connections. You get to decide what constitutes each system. If you read the revision documentation from the CMPs, that's what they intended. I've never dealt with an AHJ who required only one connection under this rule.

That said, I can't guarantee your AHJ will read it the same way. It is confusing and has been modified multiple times without ever quite saying what it means.

 

[msi99]

Thank you. Would you be able to guide me in the right direction to find a copy of the CMP's revised document?

 

[jaggedben]

Once you create an account to log into nfpa.org (basically, give them your email) you can view it all here.

NFPA 70®: National Electrical Code®

<p>90.2(C) Installations Covered.<br /><br />This Code covers the installation and removal of electrical conductors, equipment, and raceways; signaling and communications conductors, equipment, and raceways; and optical fiber cables for the following:<br /><br /> (1) Public and private...

www.nfpa.org

Navigating the revision documentation can be difficult but starts with selecting an edition and looking for documents such as First Draft Report or Second Draft Report.

 

[jaggedben]

Relevant to this question is you can find in the 2017 edition First Draft Report Public Input No. 4015-NFPA 70-2014, in which John Smirnow on behalf of SEIA stated that "Changing the word “The” to “Each” minimizes the possibility of an interpretation of this requirement to mean that only one (1) PV interconnection is allowed for all inverters on a single existing premises wiring system."

 

[msi99]

I am curious as to why the revision heading on CMP says 705.12 (D) and talks about the statement which is code 705.12(A)
"Public Input No. 4015-NFPA 70-2014 [ Section No. 705.12(D)(1) ]"

 

[wwhitney]

I am curious as to why the revision heading on CMP says 705.12 (D) and talks about the statement which is code 705.12(A)
"Public Input No. 4015-NFPA 70-2014 [ Section No. 705.12(D)(1) ]"

The language in question has apparently be jumping around a fair amount over the recent code cycles, and in the 2014 NEC it was in 705.12(D)(1). So that is the label used for PIs for proposed changes to be adopted in the 2017 NEC.

Cheers, Wayne

 

[jaggedben]

Yeah you have to be really clear what code cycle because the numbering has changed every cycle. What is now 705.11 used to be 705.12(A) (and was much shorter). What is now 705.12(A) used to be 705.12(D)(1) then was 705.12(B)(1), or 705.12(1), or something. I didn't double check all that , just trying to give you an idea.

 

[Steve16]

Great post. Was wondering about this recently and considered asking on here about a recent plan review that was submitted to me with an existing system with a line tie and new pv system with backfed breaker (20a).

All I could find (paraphrasing) was basically the 2 rapid shutdown devices need to be grouped. Nothing saying 2 separare interconnections was a violation.

 

[msi99]

Great post. Was wondering about this recently and considered asking on here about a recent plan review that was submitted to me with an existing system with a line tie and new pv system with backfed breaker (20a).

All I could find (paraphrasing) was basically the 2 rapid shutdown devices need to be grouped. Nothing saying 2 separare interconnections was a violation.

I believe that there is no regulation stating that a line side tap and a backfeed breaker cannot be allowed. However, it is important to note that the NEC 2023 edition mandates the use of a single disconnecting means to disconnect multiple power sources from the conductors of another system.

 

[msi99]

What code reference in NEC 2023 corresponds to NEC 2017 - 705.12 (A)?

 

[wwhitney]

What code reference in NEC 2023 corresponds to NEC 2017 - 705.12 (A)?

705.11

Cheers, Wayne

 

[Steve16]

I believe that there is no regulation stating that a line side tap and a backfeed breaker cannot be allowed. However, it is important to note that the NEC 2023 edition mandates the use of a single disconnecting means to disconnect multiple power sources from the conductors of another system.

Where is this? It appears 705 is mostly the same language in the 2023 as the 2020