Tapping service entrance conductors.

[Tundra5156]

Is there a code violation here? If so, site the violation. Service entrance conductors tapped before main disconnecting means in disconnect cabinet. Service entrance conductors are 4/0 and taps are #4. Tapped wires feed grid power to a PV inverter & terminate to a breaker on inverter.
Picture link provided below:

https://www.dropbox.com/s/izhefi20y7vh5cj/20210626_152435.jpg?dl=0

 

[Greentagger]

Appears to be compliant per 230.46, and 230.82(6).
Missed the part about inverter breaker. Verify compliance with 705.11. Usual installation is a fused disconnect, ahead of inverter.

 

[texie]

You need to have a disconnect w/OCPD and suitable for use as service equipment within 10 feet of the "tap". From there you go to the invertor. And it would also need a MBJ.

 

[jaggedben]

No code violation in the picture that I can see.

...And it would also need a MBJ.

I agree that would be best, but so far the code making panel has refused to be clear about it. Some think that running an SSBJ from the service panel should also be permitted.

 

[texie]

No code violation in the picture that I can see.



I agree that would be best, but so far the code making panel has refused to be clear about it. Some think that running an SSBJ from the service panel should also be permitted.

I agree that the photo seems to be OK but the OP seems imply that this directly to an inverter which would be an issue.

 

[jaggedben]

I agree that the photo seems to be OK but the OP seems imply that this directly to an inverter which would be an issue.

I agree with that, and the rest of what you said in post 3 that I didn't quote.

 

[don_resqcapt19]

No code violation in the picture that I can see.



I agree that would be best, but so far the code making panel has refused to be clear about it. Some think that running an SSBJ from the service panel should also be permitted.

They cleared this up in the 2020 code. 250.25(A) requires the disconnect for the tapped conductors to be installed in compliance with 250.24(A) through (D). 250.24(B) requires the main bonding jumper.

There is an ongoing turf war between CMP 4 who has the alternate energy systems and CMP 10 who has Article 230. Panel 10 proposed a new Article 231 that will take the place of the line side connections that are now found in 705. Not sure how that came out, but no matter which way it went, it will come up again in the second draft part of the process.

 

[electrofelon]

They cleared this up in the 2020 code. 250.25(A) requires the disconnect for the tapped conductors to be installed in compliance with 250.24(A) through (D). 250.24(B) requires the main bonding jumper.

There is an ongoing turf war between CMP 4 who has the alternate energy systems and CMP 10 who has Article 230. Panel 10 proposed a new Article 231 that will take the place of the line side connections that are now found in 705. Not sure how that came out, but no matter which way it went, it will come up again in the second draft part of the process.

I have said it many times before and I'll say it again, they should just get rid of the whole supply-side nonsense and just have it fall under the 230.40 exceptions. I don't see why we need "PV disconnects", connecting on the supply some of the "normal" disconnects, etc.

 

[romex jockey]

ahhh errhhh,,,,,.....>>>>

https://www.milbankworks.com/datasyncimg/1028693.png

~RJ~

 

[texie]

ahhh errhhh,,,,,.....>>>>

https://www.milbankworks.com/datasyncimg/1028693.png

~RJ~

That's the classy way to do it.

 

[Carultch]

I don't see why we need "PV disconnects", connecting on the supply some of the "normal" disconnects, etc.

1. Because the service disconnect is the main breaker of a panelboard, and the system can't connect under the 120% rule
2. Because the service disconnect is a breaker that is not suitable for backfeed.
3. Because the PV system is built as a separate service from the service that feeds the building loads, and therefore needs to be line-side of the service meter so it can be on its own service meter. Given hot sequence metering, this would mean you'd have to tie in on the supply side of the service disconnect.
4. Because the site has generator backup and an automatic transfer switch. And in order to avoid a control system to get the inverter and generator to play nicely together, you need to connect on the utility-side conductors of the ATS, so that the PV is off when the generator is running

What we need is a code rule to establish a consensus on what to do about neutral-to-ground bonding in supply-side interconnection disconnects, so this isn't subject to inconsistent opinions of the various AHJ's.

 

[electrofelon]

1. Because the service disconnect is the main breaker of a panelboard, and the system can't connect under the 120% rule
2. Because the service disconnect is a breaker that is not suitable for backfeed.
3. Because the PV system is built as a separate service from the service that feeds the building loads, and therefore needs to be line-side of the service meter so it can be on its own service meter. Given hot sequence metering, this would mean you'd have to tie in on the supply side of the service disconnect.
4. Because the site has generator backup and an automatic transfer switch. And in order to avoid a control system to get the inverter and generator to play nicely together, you need to connect on the utility-side conductors of the ATS, so that the PV is off when the generator is running

What we need is a code rule to establish a consensus on what to do about neutral-to-ground bonding in supply-side interconnection disconnects, so this isn't subject to inconsistent opinions of the various AHJ's.

Just briefly, just about all these situations are essentially the same thing as and could be covered under 230.40 exception number 2 (with just some modification of the disconnect grouping requirements). Consider that if I installed a new set of service entrance conductors and a service disconnect per 230.40 ex 2 just to serve my PV, I could use of the "sum of all overcurrent devices excluding the device protecting the bus bar" qualification and have the same capacity as if it was a supply-side connection.

Regarding number three, I don't see how a utility meter has anything to do with it. One can still utilize to 230.40 ex 2 (again with possible modification of the grouping requirements). If we are talking a separate service for the PV, then I don't see why we need supply-side connections. Couldn't it just be "a service" that just happens to only serve PV?

The whole supply-side thing just seems completely unnecessary to me. The concept of adding another set of service conductors ("tapping") and another service disconnect is done all the time already and it's covered under the 230.40 exceptions. Just keeping everything "normal" avoids all the confusion about "PV disconnects" vs "normal disconnects", where to bond, ambiguity when an installation can be considered 230.40 exception 2 versus a supply-side PV connection, connecting "normal" loads to a PV combiner, utilities having an issue with "tapping", etc....

 

[Greentagger]

Don’t forget barriers on service terminals on line side of disconnect. 230.62(C).

 

[kwired]

You need to have a disconnect w/OCPD and suitable for use as service equipment within 10 feet of the "tap". From there you go to the invertor. And it would also need a MBJ.

Unless something in PV sections applies, there is no length restrictions on taps to service conductors in general that wouldn't also apply to the service conductor the tap was made from (particularly distance allowed to enter a building). The tap rules in 240.21 do not apply to service conductors.

 

[texie]

Unless something in PV sections applies, there is no length restrictions on taps to service conductors in general that wouldn't also apply to the service conductor the tap was made from (particularly distance allowed to enter a building). The tap rules in 240.21 do not apply to service conductors.

I did not say that this is a tap per 240.21. That is why I put quotes around the word "tap". And, yes, something in the PVC sections applies. 705.11(C).

 

[kwired]

I did not say that this is a tap per 240.21. That is why I put quotes around the word "tap". And, yes, something in the PVC sections applies. 705.11(C).

Looks like that length restriction is new in 2020.

 

[texie]

Looks like that length restriction is new in 2020.

No, in previous editions it was in 705.31.

 

[kwired]

No, in previous editions it was in 705.31.

OK.

I don't do PV or other on site production other than occasional standby only. Not totally ignorant on those topics but certainly not up to speed on them either.