Line side disco

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GerryB

Senior Member
Location
woodbridge, ct. USA
I would like opinions and code references as to whether or not a supply side fused disconnect is "required" to be located with the main service disconnect per "grouping of disconnects" in Art 230. Or could the supply side fused disco be outside (within 10 feet) of a main disco that is inside. This is residential.
 
I am confused on what you are calling a "supply side disconnect".

Any disconnect after the service disconnect would be a load side disco in relation to the service disco.

The conductors supplying this 2nd disco would be a feeder and not service conductors and the disco need not be grouped with the service disco per article 230.
 
jumper said:
I am confused on what you are calling a "supply side disconnect".

Any disconnect after the service disconnect would be a load side disco in relation to the service disco.

The conductors supplying this 2nd disco would be a feeder and not service conductors and the disco need not be grouped with the service disco per article 230.
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Before the service disconnect.
Supply side when they bug the service entrance wires in the panel ahead of the main with insulation piercing bugs. The PV guys do it a lot if they need more than they can get from a backfed breaker.
 
GerryB said:
Before the service disconnect.
Supply side when they bug the service entrance wires in the panel ahead of the main with insulation piercing bugs. The PV guys do it a lot if they need more than they can get from a backfed breaker.
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Okay, then what you have is a set of service conductors with a service tap going to one disco and the service conductors continuing on to another disco. The tap conductors are still service conductors and the discos need to be grouped.
 
jumper said:
Okay, then what you have is a set of service conductors with a service tap going to one disco and the service conductors continuing on to another disco. The tap conductors are still service conductors and the discos need to be grouped.
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That is how I was looking at it. I read some articles where some said it wasn't really a service disconnect. The question was doing the tap inside the house at the panel and popping right back outside to the fused disconnect, by way of the 10' tap rule. But like you said if you are tapping the service conductors then it should be called a service disconnect. I was saying there should be the fused disco inside and an unfused disco outside for the array and the firemen.
 
GerryB said:
That is how I was looking at it. I read some articles where some said it wasn't really a service disconnect. The question was doing the tap inside the house at the panel and popping right back outside to the fused disconnect, by way of the 10' tap rule. But like you said if you are tapping the service conductors then it should be called a service disconnect. I was saying there should be the fused disco inside and an unfused disco outside for the array and the firemen.
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I know absolutely nada about PV, but that is a service conductor tap and a service disco and all the service discos for that set of service conductors gotta be grouped.
 
The code states that the PV disconnect does not have to be listed for use as a service disconnect. And there is discussion about whether it gets counted as one of the allowed six handles.
But most AHJs seem to feel that it should be grouped and bonded like a service disconnect.
Best answer is always to check with your AHJ or someone who has installed PV in your area before.
Also it is quite likely that your AHJ will limit the length of unfused service wires inside the house.

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My take is that the "PV disconnect" does not have to be grouped with the (other) service disconnect(s). I dont see that whether the PV disconnect is a service disconnect or not effects this. I get this result from 230.40 Exception #5 and 230.71(A). I certainly dont disagree with Goldie though about checking with the AHJ.
 
GoldDigger said:
The code states that the PV disconnect does not have to be listed for use as a service disconnect. ...
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It's debatable whether that provision ever applied to equipment for a supply side connection. But at any rate, in the 2017 code that section was totally switched up to say that a supply side disconnecting means shall be suitable for use as service equipment.
 
GerryB said:
I would like opinions and code references as to 1 whether or not a supply side fused disconnect is "required" to be located with the main service disconnect per "grouping of disconnects" in Art 230. Or could the supply side fused disco be outside (within 10 feet) of a main disco that is inside. This is residential.
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1 - I say not.
Supply-side solar is an additional "service permitted by 230.2".

I say supply-side PV discos should be both outside, and bonded/grounded separately from the main service panel.
But a lot of people don't agree with me, as you will probably see!
--
230.2 Number of Services. A building or other structure
served shall be supplied by only one service unless permitted
in 230.2(A) through (D).

(A) Special Conditions. Additional services shall be permitted to supply the following:
(5) Parallel power production systems

--
230.40 Number of Service-Entrance Conductor Sets.
Each service drop, set of overhead service conductors, set
of underground service conductors, or service lateral shall
supply only one set of service-entrance conductors.

Exception No.2: Where two to six service disconnecting
means in separate enclosures are grouped at one location
and supply separate loads from one service drop, set of
overhead service conductors, set of underground service
conductors, or service lateral, one set qf service-entrance
conductors shall be permitted to supply each or several
such service equipment enclosures.

Exception No.5: One set of service-entrance conductors
connected to the supply side of the normal service disconnecting
means shall be permitted to supply each or several
systems covered by 230.82(5) or 230.82(6).
--
230.71 Maximum Number of Disconnects.
(A) General. The service disconnecting means for each
service permitted by 230.2,
--
230.82 Equipment Connected to the Supply Side of Service
Disconnect. Only the following equipment shall be
permitted to be connected to the supply side of the service
disconnecting means:
(6) Solar photovoltaic systems, fuel cell systems, or interconnected
electric power production sources.
 
A supply side connection is not it's own service unless there's a new service point and the utility brings a new set of conductors to the premises.

PVfarmer, you could make your point just as easily with the next bit of 230.71(A), which reads: "...or for each set of service entrance conductors permitted by 230.40, Exception No. 1, 3, 4, or 5,...".

But you still have to contend with 230.72(A), which seemingly says that all the disconnects permitted in 230.71 have to be grouped.

In my opinion, if you want to get out of grouping the PV disconnect with the service disconnecting means, you might be as well off arguing that the PV is not a service.

It really would depend on what interpretations your AHJ is already strongly committed to.
 
jaggedben said:
A supply side connection is not it's own service unless there's a new service point

But you still have to contend with 230.72(A), which seemingly says that all the disconnects permitted in 230.71 have to be grouped.
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Is PV the additional service allowed by 230.2(A)(5)?
Or is it the additional set of SECs allowed by 230.40 Exception 3? (PV = accessory structure)

I say it is both.

When you have an extra set of SECs, isn't that also another service?
So either way, PV is an additional service when supply side.

"for each shall consist of 6"..."six sets of disconnects per service" means you can have 6 for loads and 6 for supply side PV.

You can have 2 sets of discos with 6 discos grouped together for each, each set of 6 can be in a different place (like inside/outside).

230.71 Maximum Number of Disconnects.
(A) General. The service disconnecting means for each
service permitted by 230.2, or for each set of service entrance
conductors permitted by 230.40, Exception No.1,
3, 4, or 5, shall consist of not more than six switches or sets
of circuit breakers, or a combination of not more than six
switches and sets of circuit breakers, mounted in a single
enclosure, in a group of separate. enclosures, or in or on a
switchboard or in switchgear. There shall be not more than
six sets of disconnects per service grouped in anyone location.

230.72 Grouping of Disconnects.
(A) General. (My note: EACH SET OF) The two to six disconnects as permitted in 230.71 shall be grouped.

---
230.2 Number of Services. A building or other structure
served shall be supplied by only one service unless permitted
in 230.2(A) through (D).

(A) Special Conditions. Additional services shall be permitted to supply the following:
(5) Parallel power production systems

--
230.40 Number of Service-Entrance Conductor Sets.
Each service drop, set of overhead service conductors, set
of underground service conductors, or service lateral shall
supply only one set of service-entrance conductors.

Exception No.3: A single-family dwelling unit and its
accessory structures shall be permitted to have one set of
service-entrance conductors run to each from a single service
drop, set of overhead service conductors, set of underground
service conductors, or service lateral.
 
I believe that there is a separate provision that requires a single common disconnect for one PV installation, whether it is load side or supply side.

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To reiterate a single family house, old 100 amp Murray panel in the basement, (very full which makes me even wonder if adding taps exceeds I think 70% fill for that?). FMC to emt to a 30 amp fused disco immediately outside.
The NEC 2014 Art 705.31 was brought up, which states a "supply side service disconnecting means (for interconnected power source), shall be located within 10 feet of the service. I don't see how this would at all supercede the grouping of disconnects. They are all "grouped in one location", whether that location is "inside or outside", IMHO.
 
GerryB said:
To reiterate a single family house, old 100 amp Murray panel in the basement, (very full which makes me even wonder if adding taps exceeds I think 70% fill for that?). FMC to emt to a 30 amp fused disco immediately outside.
The NEC 2014 Art 705.31 was brought up, which states a "supply side service disconnecting means (for interconnected power source), shall be located within 10 feet of the service. I don't see how this would at all supercede the grouping of disconnects. They are all "grouped in one location", whether that location is "inside or outside", IMHO.
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That's not what 705.31 states or means.

Quite simply, 705.31 states that overcurrent protection must be located within 10 feet of the PV System disconnecting means. As it stands, too many tradespeople hear disconnecting means and automatically think overcurrent protection is afforded by that disconnecting means. That is because Article 230 requires overcurrent protection to be integral or immediately adjacent to a service disconnecting means. No such requirement exists for a PV System disconnecting means.

Some PoCo's have their own stipulations, but there is no NEC requirement that the PV System disconnecting means be located anywhere relative to the service disconnecting means. BTW, 705.31 pretty much confirms that a line-side PV System disconnecting means is not a service disconnecting means if the OCPD can be up to 10' away.
 
I think your best bets for avoiding grouping are:

1) Argue that it is not officially a service disconnect according to the 'from a utility' language in Article 100's definition of a service. Thus 230.71 and .72 don't apply. I don't agree with this argument from a safety point of view but a number of people have made it, including Mike Holt, and some AHJs agree, I have heard.

2) Try to argue electrofelon's point that a new set of service entrance conductors gets its own group. I think the language is kinda vague, I don't see it as a slam dunk.

As I said, it really depends what ideas your AHJ is already comitted to. Have a backup plan in case the inspector fails it. Or, if it's going to be prohitive to do the job a different way, get the AHJ to definitely approve your plan before the build.
 
jaggedben said:
I think this is just another version of 'is it a service disconnect or is it not a service disconnect'. Good luck with that. It's a very unresolved debate, at least on this forum.
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Not to relight the fuse but we cannot resolve it in here as long as AHJ's don't agree. The only resolution is to do it like the AHJ wants.
 
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