NEC 2023: 705.11 "Source Connections to a Service"

[jaggedben]

I agree with Don's interpretation that the "taps" inside the building ahead of the normal main breaker will be subject the AHJ allowance , if at all. Any supply-side connection to the service entrance conductors in that panel ahead of the main that "extends" those service entrance conductors, would be beyond what is already been permitted with the existing installation.

...

Say service conductors come out of the slab directly into a gutter that branches to up to six disconnects directly above the gutter. Allowed? I would think so.

Now what is the meaningful difference between that and a supply-side tap inside existing service equipment to a disconnect immediately adjacent? I would say there is none.

Just my opinion that both should be allowed. I suppose a given AHJ could allow or disallow either one, but I'd expect them to be consistent.

 

[ggunn]

Say service conductors come out of the slab directly into a gutter that branches to up to six disconnects directly above the gutter. Allowed? I would think so.

Now what is the meaningful difference between that and a supply-side tap inside existing service equipment to a disconnect immediately adjacent? I would say there is none.

Just my opinion that both should be allowed. I suppose a given AHJ could allow or disallow either one, but I'd expect them to be consistent.

CPS in San Antonio will not allow a supply side PV interconnection inside a service equipment enclosure.

 

[jaggedben]

CPS in San Antonio will not allow a supply side PV interconnection inside a service equipment enclosure.

Thanks for adding a note that's relevant to one jurisdiction out of the entire 36,000 or so in the country.

I guess I should clarify that when I said I'd 'expect' consistency, that's really more akin to 'hope and plead for' consistency.

 

[ggunn]

Thanks for adding a note that's relevant to one jurisdiction out of the entire 36,000 or so in the country.

Having a bad day?

 

[pkhosravani]

NEC 2023:
"Part VI - Service Equipment Overcurrent Protection.
230.70 (a) (1) Readily Accessible Location. The service disconnecting means shall be installed at a readily accessible location either outside of a building or inside nearest the point of entrance of the service conductors."

Let's image we have a commercial property with an existing service with the local electric company and we install a PV system that requires just one inverter and we need to perform a supply-side connection inside the MDP which is in the electrical room in the middle of the building. That MDP is powered by the utility's service conductors which enter the MDP immediately from an underground lateral.

So if PV is now considered a "service", then wouldn't the output wires of the inverter be considered "service conductors"? Also wouldn't the "nearest point of entrance of the service conductors" be the point where the PV wires leave the outdoor PV-Utility AC Disco and punch in to the interior of the building in say EMT? Couldn't I simply install another Disconnect (this time fused) at that exact point where the conductors enter the building and why wouldn't that satisfy 230.70 (a) (1)? From there I don't see why I couldn't run my "service conductors" an unlimited length to my tap on the supply-side of the utilities service conductors inside the MDP, below the main.

That's how I'm interpreting it and maybe how other novices like me may interpret it...Or am I out to lunch?

 

[wwhitney]

So if PV is now considered a "service", then wouldn't the output wires of the inverter be considered "service conductors"?

The PV inverter doesn't create a service. Service conductors are always between the utility's transformer and the first OCPD on or inside the building.

So when you are doing a PV line-side connection, you are creating an additional short segment of service conductors between the line-side splice and your first OCPD. That is what has to comply with 230.70(A)(1). Anything on the PV-side of that OCPD is a feeder, not a service conductor.

In other words, all the terminology in Article 230 is from the utility point of view; pretend the inverter is just another load, one that happens to use negative energy. : - )

Cheers, Wayne

 

[shortcircuit2]

In other words, all the terminology in Article 230 is from the utility point of view; pretend the inverter is just another load, one that happens to use negative energy. : - )

Cheers, Wayne

Inverters use a small amout of energy <5watts refered to as Nightime Power Consumption in spec sheets and DAS equipment uses energy.
So IMO, it is a load.

 

[Steve16]

Are we finally going to call this a service disconnect as it should be in the 2023? We're at a point where this disconnecting means is required to follow all the rules of a service but the NEC has refused to call it a service disconnect. This just leads to confusion and creates a grey area between installers and AHJs

 

[Steve16]

At a quick glance it looks like 2023 705.11 D calls it a Service Disconnect but 705.20 still has Source Disconnecting Means.

Source Disconnecting Means is what is being interpreted to the disconnect after the line tap currently in the 2020

 

[ggunn]

Inverters use a small amout of energy <5watts refered to as Nightime Power Consumption in spec sheets and DAS equipment uses energy.
So IMO, it is a load.

That is a distinction without a difference. The issue is available fault current, which comes from the utility through unprotected service conductors irrespective of whether the supply side connection is to a load or a PV system. What is on the other side of the OCPD is irrelevant.

 

[jaggedben]

....

So if PV is now considered a "service", then wouldn't the output wires of the inverter be considered "service conductors"?

No. Or to precise, only that portion between the service and the first disconnect on your side of the service. The service, by definition (see article 100) are the wires that come from the utility, not the PV.

Also wouldn't the "nearest point of entrance of the service conductors" be the point where the PV wires leave the outdoor PV-Utility AC Disco and punch in to the interior of the building in say EMT?

No.

Couldn't I simply install another Disconnect (this time fused) at that exact point where the conductors enter the building and why wouldn't that satisfy 230.70 (a) (1)?

No. Well, you could, but it would satisfy no requirement.

From there I don't see why I couldn't run my "service conductors" an unlimited length to my tap on the supply-side of the utilities service conductors inside the MDP, below the main.

That's how I'm interpreting it and maybe how other novices like me may interpret it...Or am I out to lunch?

You're out to lunch. Sorry.

Wayne covered it, but the purpose of 'nearest the entrance' is to prohibit service conductors being run any distance inside the building with the full fault current from the utility and no overcurrent protection. The concern is the source of power from the utility, not the PV.

 

[jaggedben]

At a quick glance it looks like 2023 705.11 D calls it a Service Disconnect but 705.20 still has Source Disconnecting Means.

Source Disconnecting Means is what is being interpreted to the disconnect after the line tap currently in the 2020

705.20 refers to Source Disconnecting Means because it applies to either supply side (705.11) or load side (705.12) connections. It's only also a service disconnect if it follows 705.11 and is the first disconnect between the utility and premises.

 

[pv_n00b]

705.11 was completely overhauled in 2023 to make a supply side PV interconnection comply with the 230 service entrance requirements. 705.11 gives us three choices for supply side interconnections:

(A) Service Connections. An electric power production source shall be permitted to be connected to a service by one of the following methods:
(1) To a new service in accordance with 230.2(A)
(2) To the supply side of the service disconnecting means in accordance with 230.82(6)
(3) To an additional set of service entrance conductors in accordance with 230.40, Exception No. 5
These connections shall comply with 705.11(B) through (F).

They all point back to 230, so the intention is clear. The supply side PV interconnection needs to be treated as a service. 705.11(D) says:

(D) Service Disconnecting Means. A disconnecting means in accordance with Parts VI through VII of Article 230 shall be provided to disconnect all ungrounded conductors of a power production source from the conductors of other systems.

230 parts VI and VII are for the disconnecting means and overcurrent protection. 230.70(A)(1) provides the location.

230.70 General. Means shall be provided to disconnect all ungrounded conductors in a building or other structure from the service conductors.
(A) Location. The service disconnecting means shall be installed in accordance with 230.70(A)(1), (A)(2), and (A)(3).
(1) Readily Accessible Location. The service disconnecting means shall be installed at a readily accessible location either outside of a building or structure or inside nearest the point of entrance of the service conductors.

The Handbook helpfully provides the following:

No maximum distance between the point of entrance of service conductors to a readily accessible location for the installation of a service disconnecting means is specified. The authority enforcing the NEC® is responsible for the decision on how far inside the building the service-entrance conductors are allowed to travel to
the service disconnecting means. The length of service-entrance conductors should be kept to a minimum inside buildings.

I would assume that interconnection to an existing service inside a building would fall under this also. The distance from the tap to the PV disconnect is no longer mandated, it is subject to the whim of the AHJ. But the intention to keep it as short as possible can't be ignored.

 

[electrofelon]

I dont even know why they need to tell you where you can connect a PV system to. They should never have gone there, its dumb. They never should have even gotten into this line side and load side stuff. You have the busbar rules, you have an exception in 230.40, and you have an exception in 230.2 if you want to allow it its own service. That is all you need.

 

[jaggedben]

I dont even know why they need to tell you where you can connect a PV system to. They should never have gone there, its dumb. They never should have even gotten into this line side and load side stuff. You have the busbar rules, you have an exception in 230.40, and you have an exception in 230.2 if you want to allow it its own service. That is all you need.

The distinction between line side and load side rules has to do with whether there is any overcurrent protection upstream. It's still a sensible distinction. The busbar rules make no sense on the line side and their restrictions shouldn't be applied there. I'm glad to have the language to fight that battle should it come up again with any AHJ I work with.

 

[pkhosravani]

705.11 was completely overhauled in 2023 to make a supply side PV interconnection comply with the 230 service entrance requirements. 705.11 gives us three choices for supply side interconnections:

They all point back to 230, so the intention is clear. The supply side PV interconnection needs to be treated as a service. 705.11(D) says:

230 parts VI and VII are for the disconnecting means and overcurrent protection. 230.70(A)(1) provides the location.

The Handbook helpfully provides the following:

I would assume that interconnection to an existing service inside a building would fall under this also. The distance from the tap to the PV disconnect is no longer mandated, it is subject to the whim of the AHJ. But the intention to keep it as short as possible can't be ignored.

I appreciate this explanation, its been most helpful.


Sent from my iPhone using Tapatalk

 

[electrofelon]

The distinction between line side and load side rules has to do with whether there is any overcurrent protection upstream. It's still a sensible distinction. The busbar rules make no sense on the line side and their restrictions shouldn't be applied there. I'm glad to have the language to fight that battle should it come up again with any AHJ I work with.

Just because there isnt a disconnect/overccurrent protection there, I dont see why the NEC should bother telling you that you may add one. IF I install a new HVAC unit and the panel is full or not suitable for some reason, I am free to add another service panel per 230.40 exception 2 and connect it there. Why does the NEC need to give me permimssion to do that for PV? The rules were already there for if a "load side" connection wasnt suitable, all they did is do something unneccesary and make a mess.

 

[jaggedben]

Just because there isnt a disconnect/overccurrent protection there, I dont see why the NEC should bother telling you that you may add one. IF I install a new HVAC unit and the panel is full or not suitable for some reason, I am free to add another service panel per 230.40 exception 2 and connect it there. Why does the NEC need to give me permimssion to do that for PV? The rules were already there for if a "load side" connection wasnt suitable, all they did is do something unneccesary and make a mess.

I think the historical answer is ....

• The original 705.12(A) (actually it was part of 690) was really short and intended no more than what you say, but chose a poor way to go about it.
• That poor language opened up interpretations that were actually more lenient than 230 allows, and some people in the PV industry fought to keep those options.
• They eventually lost, and now it says exactly what you're saying.
• Because there are so many dumb solar installers who know nothing about Article 230 (present company excluded!) they have to spell it out and beat everybody over the head with it.

I still appreciate that the code spells out what is permitted, because I know in the early days AHJs were hella confused. 690 had state that a load side PV disconnect didn't have to be service rated because people found other power sources so mind boggling. But I agree that if the code had originally said something along the lines of 'shall be permitted to connect to any service or set of service entrance conductors permitted by article 230' that would have been better.

 

[pv_n00b]

Just because there isnt a disconnect/overccurrent protection there, I dont see why the NEC should bother telling you that you may add one. IF I install a new HVAC unit and the panel is full or not suitable for some reason, I am free to add another service panel per 230.40 exception 2 and connect it there. Why does the NEC need to give me permimssion to do that for PV? The rules were already there for if a "load side" connection wasnt suitable, all they did is do something unneccesary and make a mess.

If it were easy anyone could do it. Don't mess it up for the rest of us. Lawyers and doctors don't make money by making the law and medicine easy for everyone to understand.

 

[ggunn]

Pertinent to the original question, under present and previous versions of the NEC, whenever conductor lengths are/were limited for supply side PV interconnections, there is/was an exception to the rule when cable limiters are/were used. How will the 2023 NEC address this, or will it?