Kern County and 705.12(D)

[anndee4444]

I am stuck in a battle with Kern County (California) over their interpretation of 705.12(D), and am hoping that someone might have ideas on other ways to get them to agree with my interpretation. I am attempting to use this section to get out of the (D)(1) through (D)(7) requirements, specifically the 120% rule.

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Where distribution equipment, including switchgear, switchboards, or panelboards, is fed simultaneously by a primary source(s) of electricity and one or more utility-interactive inverters, and where this distribution equipment is capable of supplying multiple branch circuits or feeders, or both, the interconnecting provisions for the utility-interactive inverter(s) shall comply with 705.12(D)(1) through (D)(6).


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Our equipment is NOT capable of supplying multiple branch circuits, and not capable of feeding multiple feeders. Kern County's interpretation of this section is that 'multiple' does not apply to 'feeders' (only branch circuits). I have tried explaining that if this was the intent of the code, there would be an additional comma after 'multiple branch circuits'. They didn't like this. :thumbsdown:

I have also tried arguing that if the definition of 'Feeder' is "circuit conductors between the service equipment... and the final branch-circuit overcurrent device.", then Feeders should mean multiple devices. They did not like this either. :thumbsdown: They gave the excuse that 'Feeder' is never used in the code (it is... 474 times. Feeders is used 239 times)

I have contacted the California Building Standards Commission, who referred me to the Office of the State Fire Marshall. I am waiting for a call back right now, but even if I do get OSFM to agree with my interpretation, Kern County does not have to agree.


Does anyone have any ideas of how I can get them to agree with my interpretation? Is my interpretation incorrect?

 

[GoldDigger]

A key question I have is whether there are loads connected to the distribution equipment.
My interpretation for the "multiple" qualification" in the text is that multiple output OCPDs allow for the possibility of the sum of the current ratings being greater than the equipment rating even though there are two sources.
If you have only one (or zero) output breaker, it is not possible to draw more than the device rating and the simple 100% rule would apply.

Sent from my XT1585 using Tapatalk

 

[gadfly56]

I am stuck in a battle with Kern County (California) over their interpretation of 705.12(D), and am hoping that someone might have ideas on other ways to get them to agree with my interpretation. I am attempting to use this section to get out of the (D)(1) through (D)(7) requirements, specifically the 120% rule.

​

Where distribution equipment, including switchgear, switchboards, or panelboards, is fed simultaneously by a primary source(s) of electricity and one or more utility-interactive inverters, and where this distribution equipment is capable of supplying multiple branch circuits or feeders, or both, the interconnecting provisions for the utility-interactive inverter(s) shall comply with 705.12(D)(1) through (D)(6).


​

Our equipment is NOT capable of supplying multiple branch circuits, and not capable of feeding multiple feeders. Kern County's interpretation of this section is that 'multiple' does not apply to 'feeders' (only branch circuits). I have tried explaining that if this was the intent of the code, there would be an additional comma after 'multiple branch circuits'. They didn't like this. :thumbsdown:

I have also tried arguing that if the definition of 'Feeder' is "circuit conductors between the service equipment... and the final branch-circuit overcurrent device.", then Feeders should mean multiple devices. They did not like this either. :thumbsdown: They gave the excuse that 'Feeder' is never used in the code (it is... 474 times. Feeders is used 239 times)

I have contacted the California Building Standards Commission, who referred me to the Office of the State Fire Marshall. I am waiting for a call back right now, but even if I do get OSFM to agree with my interpretation, Kern County does not have to agree.


Does anyone have any ideas of how I can get them to agree with my interpretation? Is my interpretation incorrect?

Move to NJ. The state can overrule the local AHJ. And they (the state) get cranky when local yokels start making up shirt pocket rules.

Seriously, you seem to have fallen into a situation where invincible ignorance rules. Is there a local construction board of appeals you can go to, or would it be cheaper and easier to just comply?

 

[GoldDigger]

Complying might involve grossly oversized distribution equipment or, better if allowed, a supply side connection.

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[wwhitney]

What does the equivalent section in the 2017 NEC have to say about what you'd like to do? If it is clearly allowed under the 2017 NEC, that might help convince the people you are dealing with that they are misinterpreting the 2014 NEC. Or perhaps they would give you permission to follow the 2017 NEC under section 90.4.

Cheers, Wayne

 

[anndee4444]

What does the equivalent section in the 2017 NEC have to say about what you'd like to do? If it is clearly allowed under the 2017 NEC, that might help convince the people you are dealing with that they are misinterpreting the 2014 NEC. Or perhaps they would give you permission to follow the 2017 NEC under section 90.4.

Cheers, Wayne

The 2017 NEC is unchanged. I have already submitted comments for the 2020 NEC to be updated to clarify this issue.

 

[anndee4444]

A key question I have is whether there are loads connected to the distribution equipment.
My interpretation for the "multiple" qualification" in the text is that multiple output OCPDs allow for the possibility of the sum of the current ratings being greater than the equipment rating even though there are two sources.
If you have only one (or zero) output breaker, it is not possible to draw more than the device rating and the simple 100% rule would apply.

Sent from my XT1585 using Tapatalk

There is one load connected to the distribution equipment (it is a large ag pump). A single line diagram would just be a straight line:

Utility --> 800A service disconnect breaker --> 800A load breaker --> 800A load​

There is no busbar for distribution, and the main breaker feeds only the one load. This is why the interpretation of if 'feeders' is for multiple devices can mean the difference of the 120% rule or not.


Also, a line side connection (tap) is not possible on this panel.

 

[ggunn]

I am stuck in a battle with Kern County (California) over their interpretation of 705.12(D), and am hoping that someone might have ideas on other ways to get them to agree with my interpretation. I am attempting to use this section to get out of the (D)(1) through (D)(7) requirements, specifically the 120% rule.

​

Where distribution equipment, including switchgear, switchboards, or panelboards, is fed simultaneously by a primary source(s) of electricity and one or more utility-interactive inverters, and where this distribution equipment is capable of supplying multiple branch circuits or feeders, or both, the interconnecting provisions for the utility-interactive inverter(s) shall comply with 705.12(D)(1) through (D)(6).


​

Our equipment is NOT capable of supplying multiple branch circuits, and not capable of feeding multiple feeders. Kern County's interpretation of this section is that 'multiple' does not apply to 'feeders' (only branch circuits). I have tried explaining that if this was the intent of the code, there would be an additional comma after 'multiple branch circuits'. They didn't like this. :thumbsdown:

I have also tried arguing that if the definition of 'Feeder' is "circuit conductors between the service equipment... and the final branch-circuit overcurrent device.", then Feeders should mean multiple devices. They did not like this either. :thumbsdown: They gave the excuse that 'Feeder' is never used in the code (it is... 474 times. Feeders is used 239 times)

I have contacted the California Building Standards Commission, who referred me to the Office of the State Fire Marshall. I am waiting for a call back right now, but even if I do get OSFM to agree with my interpretation, Kern County does not have to agree.


Does anyone have any ideas of how I can get them to agree with my interpretation? Is my interpretation incorrect?

Under the 2014 NEC you can qualify a busbar for backfeeding if:
a) 125% of the inverter nameplate current feeding your backfed breaker (anywhere on the bus) plus the OCPD protecting the busbar sum to 100% or less than the busbar rating.

b) Your backfed breaker is located at the opposite end of the busbar from the OCPD protecting it, and 125% of the inverter nameplate current feeding it plus the OCPD protecting the busbar sum to 120% or less than the busbar rating (the 120% rule).

c) All the breakers (load and backfed) connected to the busbar but disregarding the OCPD protecting the busbar sum to 100% or less than the rating of the busbar. This is the new one that legitimizes AC combiner panels that don't comply with the 120% rule.

d) You run engineering studies backed up by a lot of data and you can get a PE to sign off on it.

The rules are pretty clear and there is no other way AFAIK.

 

[wwhitney]

c) All the breakers (load and backfed) connected to the busbar but disregarding the OCPD protecting the busbar sum to 100% or less than the rating of the busbar. This is the new one that legitimizes AC combiner panels that don't comply with the 120% rule.

I don't understand why 705.12(D)(2)(c) was written this way--wouldn't it be sufficient to either sum all the supply breakers, or sum all the load breakers, and if either sum is less than the ampacity rating of the busbar, then the busbar is adequately protected? If 705.12(D)(2)(c) were written that way, it would cover the OP's situation.

As to the OP, I think if Kern County is going to misread 705.12(D) as you describe, you are stuck. I agree with your reading of 705.12(D), that if there can be only one load breaker in the equipment, 705.12(D)(1) through (6) do not apply.

Cheers, Wayne

 

[jaggedben]

...Our equipment is NOT capable of supplying multiple branch circuits, and not capable of feeding multiple feeders. Kern County's interpretation of this section is that 'multiple' does not apply to 'feeders' (only branch circuits). I have tried explaining that if this was the intent of the code, there would be an additional comma after 'multiple branch circuits'. They didn't like this. :thumbsdown:

...

I'm trying to imagine what equipment you are dealing with where this description makes sense. If it's not capable of supplying multiple of either, then what difference does a comma make? In my experience, if you have a panelboard, then nearly by definition ("automatic overcurrent devices", plural) it is capable of feeding multiple branch circuits or feeders, or both. Unless this debate is about a circuit breaker enclosure or disconnect that is being incorrectly considered to be a panelboard, then my best guess is that I probably agree with the county's point of view about the rules that apply. But note that in the 2014 code the 120% rule (and the others ggunn described for you) only apply to panelboards, so if it isn't a panelboard, then that might be your last good bet at changing their minds. The other possibility might be if the busbars are on the supply side of the service disconnecting means, then the rules also don't apply.

To be more succint, it's hard to help without knowing the details of the equipment and setup.

 

[ggunn]

I'm trying to imagine what equipment you are dealing with where this description makes sense. If it's not capable of supplying multiple of either, then what difference does a comma make? In my experience, if you have a panelboard, then nearly by definition ("automatic overcurrent devices", plural) it is capable of feeding multiple branch circuits or feeders, or both. Unless this debate is about a circuit breaker enclosure or disconnect that is being incorrectly considered to be a panelboard, then my best guess is that I probably agree with the county's point of view about the rules that apply. But note that in the 2014 code the 120% rule (and the others ggunn described for you) only apply to panelboards, so if it isn't a panelboard, then that might be your last good bet at changing their minds. The other possibility might be if the busbars are on the supply side of the service disconnecting means, then the rules also don't apply.

To be more succint, it's hard to help without knowing the details of the equipment and setup.

Agreed, and I'll just add that just because a panelboard doesn't supply feeders or branches in a particular application does not mean that it is incapable of doing so. It seems to me that the language is meant to distinguish between panelboards and devices such as enclosed circuit breakers.

 

[wwhitney]

Agreed, and I'll just add that just because a panelboard doesn't supply feeders or branches in a particular application does not mean that it is incapable of doing so. It seems to me that the language is meant to distinguish between panelboards and devices such as enclosed circuit breakers.

I would think that if a panelboard is filled by the incoming utility breaker, the incoming alternate source breaker, and the outgoing feeder breaker, then it would be exempt from the 705.12(D) subitem requirements. For example, I have a meter main on my house with room for just one main breaker and two additional double pole breakers.

Cheers, Wayne

 

[jaggedben]

I would think that if a panelboard is filled by the incoming utility breaker, the incoming alternate source breaker, and the outgoing feeder breaker, then it would be exempt from the 705.12(D) subitem requirements. For example, I have a meter main on my house with room for just one main breaker and two additional double pole breakers.

I don't agree. First, it is feeding both a feeder and a branch circuit, which is the 'or both' in the language. This argument over commas and plurals is one I would never make to an AHJ with a serious expectation of winning the point. But on a broader level, it is a panelboard with busbars that are are listed to a certain standard. Whatever safety issues justify rules that apply to those, those issues are still in play. The issue is knowing that the thermal output of both the utility and inverter breaker together won't damage the busbar. If anything, having a smaller busbar with less room for thermal dissipation makes the problem worse. If any busbar should be exempted (to be clear, none are) it would be the one that's 3ft long in a 42 circuit panel.

 

[wwhitney]

I don't agree. First, it is feeding both a feeder and a branch circuit, which is the 'or both' in the language.

Sorry, I don't see that. In my example, in the language of 705.12(D), the panel is "fed" by the utility and the alternate source and is "supplying" just one feeder, and there is no room for another breaker to supply another feeder or branch circuit. With all loads supplied through one breaker, how can the bus ever be overloaded?

Cheers, Wayne

 

[anndee4444]

To be more succint, it's hard to help without knowing the details of the equipment and setup.

Yeah, I should have described the equipment in the original post.

We have an 800A meter-main with only one 800A service disconnect, and no bus for additional disconnects or branch circuits. The service disconnect feeds directly to an 800A breaker (Pump Breaker) in an adjacent panel with no bus or room for any additional breakers. There is a single 800A load after the pump breaker (it is a large ag pump). We are attempting to tap on the load side conductors between the service disconnect & pump breaker. A line side tap/connection is not possible in this panel. We are backfeeding close to 800A of PV, so complying with the 120% rule is out of the question. This is an aggregate NEM array, which is why the PV is so large.


To further clarify the issue we are having: We are interpreting 705.12(D) as though our distribution equipment is not capable of supplying multiple branch circuits, or multiple feeders (it only supplies 1 feeder to the pump breaker). This would exempt us from the 120% rule and the rest of (D)(1) through (D)(6).

The AHJ's interpretation is that "multiple branch circuits or feeders" means multiple branch circuits, and that multiple does not apply to feeders... so feeding a single breaker would not exempt (D)(1) through (D)(6).


My interpretation: …and where this distribution equipment is capable of supplying

1.multiple​

​a. branch circuits
​

b. or feeders,
​

2. or both,​

Kern County's interpretation: …and where this distribution equipment is capable of supplying

1. multiple branch circuits
2. or feeders, (not multiple)
3. or both,

​

​If the sentence was written with the comma shown in red "...capable of supplying multiple branch circuits, or feeders, or both" then I would agree the AHJ could interpret multiple as not applying to feeders, despite feeder being plural. But it's not, and there is no comma after branch circuits. It is "...capable of supplying multiple branch circuits or feeders, or both".

 

[wwhitney]

We have an 800A meter-main with only one 800A service disconnect, and no bus for additional disconnects or branch circuits. The service disconnect feeds directly to an 800A breaker (Pump Breaker) in another panel that is 1' away. There is a single 800A load after the pump breaker (it is a large ag pump). We are attempting to tap on the load side conductors between the service disconnect & pump breaker.

Seems to me this scenario falls under (2014) 705.12(D)(2)(1), as you are making the inverter output connection at the feeder rather than at the service disconnect.

Cheers, Wayne

 

[anndee4444]

Seems to me this scenario falls under (2014) 705.12(D)(2)(1), as you are making the inverter output connection at the feeder rather than at the service disconnect.

Cheers, Wayne

My interpretation is that we are exempt from the second sentence of 705.12(D), and the only part that applies is the first sentence:

"The output of a utility-interactive inverter shall be permitted to be connected to the load side of the service disconnecting means of the other source(s) at any distribution equipment on the premises."
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Since the second sentence is not true, then we do not have to "comply with 705.12(D)(1) through (D)(6)", including 705.12(D)(2)(1).

 

[ggunn]

I would think that if a panelboard is filled by the incoming utility breaker, the incoming alternate source breaker, and the outgoing feeder breaker, then it would be exempt from the 705.12(D) subitem requirements. For example, I have a meter main on my house with room for just one main breaker and two additional double pole breakers.

Cheers, Wayne

Yes, but that is a characteristic of the application, not of the piece of gear itself. It's the gear itself that I believe that the code is referring to. It says "...is capable of feeding...", not "....is feeding...". Your point is that the application makes it incapable. The governing AHJ does not agree, apparently.

 

[anndee4444]

Sorry, I don't see that. In my example, in the language of 705.12(D), the panel is "fed" by the utility and the alternate source and is "supplying" just one feeder, and there is no room for another breaker to supply another feeder or branch circuit. With all loads supplied through one breaker, how can the bus ever be overloaded?

Cheers, Wayne

I agree. If there is nothing but one correctly sized OCPD at either end of a bus bar or conductor, there is no way that it can ever be overloaded by PV backfeed.

 

[anndee4444]

It says "...is capable of feeding...", not "....is feeding...". Your point is that the application makes it incapable. The governing AHJ does not agree, apparently.

This is a good point... The AHJ is not currently arguing this, but I could see them changing to it, since technically ANYTHING is capable of supplying multiple feeders with enough determination/stupidity (code compliant or not).