Is there any way to clarify interconnection for PV system into existing gear?

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mooreaaryan

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Bakersfield CA
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Electrician
I just got involved with a company focused on commercial solar. Throughout the past few weeks I have been trying to get clarity on whats codes actually apply (field installers point one way and engineers point the other)

My first site has existing Switch Board fed by the utility and is designated the point of interconnection. The service is 600 amps from utility. The new PV is also 600amp.
as of my understanding right now I cannot connect the PV 600amp to an OCPD on the Switchboard bussing due to the 120% rule, i am limited to 96amps. So i must connect the PV 600amp to the bussing directly between the meter and main breaker.

how does an engineer determine the physical point of connection? why would not landing on the breaker be acceptable?
Should i be looking at the conductors from the PV to the Switchboard strictly as taps?
Do i need to provide short circuit protection to these conductors.


FYI-My first OCPD for the solar is 31 foot in length of wire away from the proposed point of interconnection.
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Landing on the line side terminals of the main breaker is acceptable if open lugs are there or can be installed. You cannot land on the load side of the MCB because that would supply 1200A to a 600A bus.
 
The general answer is: read article 705 in the NEC. Particularly 705.11 and 705.12. Also note that the rules have changed continuously over the last few code cycles so pay attention to which version of the NEC applies to the permit.
 
electrofelon said:
Okay, it's a free country.... but it says what it says and panel boards are very different from switchboards so I don't see that as any sort of mistake or loophole.
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But wasn't the language in 705.12 expanded to include both?
 
electrofelon said:
Yes, in 2020 IIRC? I haven't dug into the reasons as it's pointless, the CMP'S are all over the place and can't settle on anything. They'll probably change it back next cycle.
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This is all infighting between CMPs 4, 5, and 10...to the extent that CMP 10 had a new article in the first revision for the 2023 code. It would have been Article 231 Electric Power Sources Interconnected with an Electric Utility and taken control of all of the interconnection stuff in 705. The CCC forced a task group to work on this and that group made the changes we see between the 2020 and the 2023 codes.
 
electrofelon said:
Well even if PV conductors were definitely NOT service conductors, one would still be tapping onto a service conductors for a line side tap right?
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Yes. 230.46 prohibits this for Polaris blocks, IPCs, etc. unless and until they are marked listed for service conductors. AFAIK, the only compliant products so far are two port Polaris blocks, which are useless for connecting PV to service conductors.
 
ggunn said:
AFAIK, the only compliant products so far are two port Polaris blocks, which are useless for connecting PV to service conductors.
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This 2 port such product says that it has double-sided entry ports, is suitable from 350 MCM to #10 gauge, and is suitable for service conductors per NEC 230.46. (I thought there was no listing standard for that yet, so I'm not clear on what basis they state that.)


Given that, it seems like you could use them for a running tap, as long as the service conductor insulated OD is less than the 350MCM bare OD, by stripping a section of insulation off the middle of the conductor and sliding one port over the insulated portion to the exposed conductor.

Cheers,
Wayne

P.S. If there's no listing standard for pressure connectors for the marking called out in 230.46, and seeing as how the NEC does not define "marked" or use it exclusively to mean "marked in accordance with a listing requirement," seems to me that 230.46 permits field marking on the basis of professional judgement.
 
ggunn said:
This may have changed, but what Polaris has always meant by that was that you could enter the port from either side but not both.
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What I proposed will work in practice, and has been suggested here multiple times. Do the instructions rule it out? If not, what's the problem?

Edit: I guess the question is moot, as the product manufacturer's comment about 230.46 is not limited to the 2-port version, it appears on the spec sheet for the entire product line: "Connector sizes 350 to 750 MCM are suitable for use on the line side of the
service equipment per NEC 230.46 requirements."

Click on the instructions on the product page, or see POL_BLK-VT_MCH_ProdInstall_DIGITAL.pdf at https://cdn.amplifi.pattern.com/fb4d416f-d614-48a7-b7de-a8f8615f501d

See also: https://www.nsiindustries.com/line-side-SKUs/

Cheers, Wayne
 
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wwhitney said:
What I proposed will work in practice, and has been suggested here multiple times. Do the instructions rule it out? If not, what's the problem?

Edit: I guess the question is moot, as the product manufacturer's comment about 230.46 is not limited to the 2-port version, it appears on the spec sheet for the entire product line: "Connector sizes 350 to 750 MCM are suitable for use on the line side of the
service equipment per NEC 230.46 requirements."

Click on the instructions on the product page, or see POL_BLK-VT_MCH_ProdInstall_DIGITAL.pdf at https://cdn.amplifi.pattern.com/fb4d416f-d614-48a7-b7de-a8f8615f501d

See also: https://www.nsiindustries.com/line-side-SKUs/

Cheers, Wayne
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Oh, I see what you mean - running the service conductor all the way through and the PV conductor into the other port, right? If the rest of the product line is now listed, though, that could explain why Austin Energy started enforcing 230.46 on August 1. Thanks.
 
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