225.32 'nearest the point of entrance' 230.6

[tortuga]

I am pondering the case of additional feeders between buildings and where the disconnects need to be located.
Simple right?
Say for example in my case two 'additional' feeders, a parallel power production and an optional standby generator feeder as permitted in 225.30(A)(4) and (5). The building call it building 'B' is supplied by a primary feeder from another building, Building 'A'. Building 'A' contains the service point.
The two additional feeders between buildings have the source and supply reversed with respect to the service point.
So how is 225.32 and thus the referenced 230.6 interpreted when the feeder travels a distance from the source inside the building 'B' then exits to its destination building 'A'?
Is the 230.6 'nearest the point of entrance' the feeder source at building 'B', I.E the generator or inverter?
Or is the 230.6 'nearest the point of entrance' where the feeder 'exits' building 'B' heading say underground towards building 'A' the service point.

Thoughts? Opinions?

Thanks in advance.

 

[david]

I am pondering the case of additional feeders between buildings and where the disconnects need to be located.
Simple right?
Say for example in my case two 'additional' feeders, a parallel power production and an optional standby generator feeder as permitted in 225.30(A)(4) and (5). The building call it building 'B' is supplied by a primary feeder from another building, Building 'A'. Building 'A' contains the service point.
The two additional feeders between buildings have the source and supply reversed with respect to the service point.
So how is 225.32 and thus the referenced 230.6 interpreted when the feeder travels a distance from the source inside the building 'B' then exits to its destination building 'A'?
Is the 230.6 'nearest the point of entrance' the feeder source at building 'B', I.E the generator or inverter?
Or is the 230.6 'nearest the point of entrance' where the feeder 'exits' building 'B' heading say underground towards building 'A' the service point.

Thoughts? Opinions?

Thanks in advance.

The point of entrance is always where supply conductors enter the building

 

[tortuga]

The point of entrance is always where supply conductors enter the building

Assuming the supply is the generator or inverter then your saying a disconnect next to them serves this purpose?

 

[david]

Assuming the supply is the generator or inverter then your saying a disconnect next to them serves this purpose?

OK i am under the 2008 NEC so i always need to check everything for different code cycles.

 

[david]

Unless you fall under an exception the disconnecting means to separate the building from the supply has to be attached to or inside the supplied building “nearest point of supply

2008 NEC

225.32 Location.
The disconnecting means shall be installed either inside or outside of the building or structure served or where the conductors pass through the building or structure. The disconnecting means shall be at a readily accessible location nearest the point of entrance of the conductors. For the purposes of this section, the requirements in 230.6 shall be utilized.
Exception No. 1: under single management,
Exception No. 2: provisions of Article 685,
Exception No. 3: For towers or poles used as lighting standards,
Exception No. 4: For poles or similar structures used only for support of signs

 

[tortuga]

Unless you fall under an exception the disconnecting means to separate the building from the supply has to be attached to or inside the supplied building “nearest point of supply

2008 NEC

225.32 Location.
The disconnecting means shall be installed either inside or outside of the building or structure served or where the conductors pass through the building or structure. The disconnecting means shall be at a readily accessible location nearest the point of entrance of the conductors. For the purposes of this section, the requirements in 230.6 shall be utilized.

Yeah its pretty much the same in 2014 NEC.
So in my example case there are 3 feeders between 2 buildings building 'A' and 'B'. Call the feeders 1,2 and 3.
Feeder 1 Supplies all of Building B's loads from a MDP in building 'A'. The disconnect is in the normal spot.
The MDP in building 'A' can utilise power from the utility, the solar or the generator as needed to feed building 'B' via feeder 1.
Feeder 2 supplies the MDP in building 'A', its disconnect is at the Generator on building 'B'.
Feeder 3 is a Parallel Power production System supplying power to building 'A' (Grid tie Solar Inverter). Its disconnect would be at a interior location where the source power (Inverter) begins.

Here I'll attach a sketch:

So would you say the 'source' of feeders 2 and 3 are the generator and inverter, respectively?

 

[david]

Under normal conditions feeder 2 (GEN) would need a building disconnect before passing through or supplying building A'S transfer switch.

I need to look closely at 690 and 705 for changes from 2008 before commenting

you could post that portion of your question to the solar forum for a faster response

 

[tortuga]

Under normal conditions feeder 2 (GEN) would need a building disconnect before passing through or supplying building A'S transfer switch.

I need to look closely at 690 and 705 for changes from 2008 before commenting

you could post that portion of your question to the solar forum for a faster response

My sketch was quick and not clear all 3 feeders meet 230.6 where they enter building 'A'.
The transition at building 'B' I have the question about.
Feeder 2 and 3 have no disconnect where they 'exit' building B.

 

[david]

My sketch was quick and not clear all 3 feeders meet 230.6 where they enter building 'A'.
The transition at building 'B' I have the question about.
Feeder 2 and 3 have no disconnect where they 'exit' building B.

a feeder upon exiting a building is not required a disconnect unless there is something in 690 or 705 that requires this in a change from 2008

 

[tortuga]

a feeder upon exiting a building is not required a disconnect unless there is something in 690 or 705 that requires this in a change from 2008

Yeah I think I agree it looks really wrong at first, because I am looking at feeder 2 and 3 from the perspective of the service point.
Then they are 'entering' the building by attaching to the exterior. (230.6)
Well thanks for the input
Cheers

 

[wwhitney]

Why wouldn't Feeder 3 need a disconnect on the exterior of building B (or nearest the point of entrance)? If you grant Feeder 3 is subject to 225.30, then for the purposes of 225 it is supplying Building B, and 225.31 would apply.

As a practical matter, isn't the idea that you should be able to disconnect all external power sources from the building by these disconnects on or in the building? Without such a disconnect, the only way to deenergize Feeder 3 is to go to building A.

Cheers, Wayne

 

[tortuga]

Why wouldn't Feeder 3 need a disconnect on the exterior of building B (or nearest the point of entrance)? If you grant Feeder 3 is subject to 225.30, then for the purposes of 225 it is supplying Building B, and 225.31 would apply.

As a practical matter, isn't the idea that you should be able to disconnect all external power sources from the building by these disconnects on or in the building? Without such a disconnect, the only way to deenergize Feeder 3 is to go to building A.

Cheers, Wayne

Yeah thats my question. Here is a better diagram:
Both feeders 2 and 3 are pipe on the outside of the building, then head underground to building A.
According to 225.32's 230.6 reference Feeders 2 and 3 enter building 'B' as soon as they exit their power sources (the generator and inverter). They exit building B at the arrow per 230.6's definition and supply building A.
The logic is that the feeders 2 and 3 begin in building 'B' and therefore those are exits not entrances. And thus 225.32 requires the disconnects next to the power source.
As a practical matter I see the 'exit' as where conductors enter.
More info:
Feeder 3 is not installed, Feeder 2 is existing and probably passed an inspection.
Feeder 3 will actually travel in EMT on the exterior and only penetrate the wall into the back of the disconnect.
Feeder 3 happens to be run on the concrete stem wall in EMT, Feeder 2 the existing is PVC on the siding.
All of which I think is moot
Thanks for your feedback.

 

[david]

My sketch was quick and not clear all 3 feeders meet 230.6 where they enter building 'A'.
The transition at building 'B' I have the question about.
Feeder 2 and 3 have no disconnect where they 'exit' building B.

Why wouldn't Feeder 3 need a disconnect on the exterior of building B (or nearest the point of entrance)? If you grant Feeder 3 is subject to 225.30, then for the purposes of 225 it is supplying Building B, and 225.31 would apply.

As a practical matter, isn't the idea that you should be able to disconnect all external power sources from the building by these disconnects on or in the building? Without such a disconnect, the only way to deenergize Feeder 3 is to go to building A.

Cheers, Wayne

He states building A is taken care of where feeders or service enter that building.

His question seems to only address where feeders 2 and 3 exit building B to supply building A

Feeder one is the supply feeder from Building A to Building B he states it has a disconnect and has passed an inspection

Feeder 3 seems to be from a solar array with a interactive inverted system supplying what seems to be a line side of the service connection to building A. he is calling the exit point the point where feeder 2 and 3 go under ground from the best i can tell

 

[tortuga]

He states building A is taken care of where feeders or service enter that building.

His question seems to only address where feeders 2 and 3 exit building B to supply building A

Feeder one is the supply feeder from Building A to Building B he states it has a disconnect and has passed an inspection

Feeder 3 seems to be from a solar array with a interactive inverted system supplying what seems to be a line side of the service connection to building A. he is calling the exit point the point where feeder 2 and 3 go under ground from the best i can tell

Yeah that's correct. At building 'A' all the feeders enter as in 230.6 directly under the MDP and land on properly sized OCPD's.
So OCPD's on each end of all feeders actually. Feeder 1 has a 225.32 disconnect where it 'enters'. At that same location Feeder 2 does not have one where it 'exits'. And yes Feeder 3 is for new solar grid tied inverter.

I will be conferring with the building official of course but just curious what the wisdom here thinks.
If feeder 3 needs a disconnect at the exit then feeder 2 would also.
Thus in that scenario a expensive modification of feeder 2 and possibly a back charge for generator installer.
Building is brand new so all new code.

Thanks all!

 

[wwhitney]

OK, Feeder 3 "exits" Building B and runs to the service on Building A, in the sense that when the inverters are generating power that is the direction of power flow. But Feeder 3 is still connected to the utility, and in the event of a fault on the feeder inside Building B, power will be entering Building B from the service at that normal "exit point".

Thus I would say that 225.31 does require a disconnect at Building B for Feeder 3. However, from the updated diagram, the disconnect for Feeder 3 at Building B will be inside "nearest the point of entrance", so the 225.32 requirement is complied with and all is well.

On the updated diagram, looks like Feeder 2 doesn't enter Building B at all, the exterior disconnect is probably the one required for the generator itself.

Cheers, Wayne

 

[david]

I had this discussion here with the solar guys on their installs , we do not get a lot of solar here but it does come up, it seems what the OP is showing is a combiner panel from the solar interactive inverters output .

The solar guys here mark that solar equipment only.

Here there would be a main breaker that combines the individual inverter outputs to send the solar output originating at building B to the utility service equipment at building A.

Not saying your incorrect just need to read 690 and 705 again

 

[tortuga]

OK, Feeder 3 "exits" Building B and runs to the service on Building A, in the sense that when the inverters are generating power that is the direction of power flow. But Feeder 3 is still connected to the utility, and in the event of a fault on the feeder inside Building B, power will be entering Building B from the service at that normal "exit point".

Thus I would say that 225.31 does require a disconnect at Building B for Feeder 3. However, from the updated diagram, the disconnect for Feeder 3 at Building B will be inside "nearest the point of entrance", so the 225.32 requirement is complied with and all is well.

On the updated diagram, looks like Feeder 2 doesn't enter Building B at all, the exterior disconnect is probably the one required for the generator itself.

Cheers, Wayne

I tend to agree, however it could be argued the feeder is also protected by the back fed OCPD at building 'A' thus its protected at each end... And the the curious part is 225.32 references 230.6:

230.6 Conductors Considered Outside the Building. Conduc-
tors shall be considered outside of a building or other structure
under any of the following conditions:
(1)Where installed under not less than 50 mm (2 in.) of con-
crete beneath a building or other structure(2) Where installed within a building or other structure in a
raceway that is encased in concrete or brick not less than
50 mm (2 in.) thick
(3) Where installed in any vault that meets the construction
requirements of Article 450, Part III
(4) Where installed in conduit and under not less than 450 mm
(18 in.) of earth beneath a building or other structure
(5) Where installed within rigid metal conduit (Type RMC)
or intermediate metal conduit (Type IMC) used to accom-
modate the clearance requirements in 230.24 and routed
directly through an eave but not a wall of a building

230.6 is defining all the cases when a conductor is considered outside a building, if its not in 1-5 its inside....
Anything even attached to a building exterior is thus considered 'inside', Unless it is in 1-5 of 230.6.
Once the conduit comes up from the trench and attaches to the side of the building (like at the 'exit arrow') they are considered 'inside' the building and a 3rd disconnect is required at that point, regardless of direction of current flow.

Here there would be a main breaker that combines the individual inverter outputs to send the solar output originating at building B to the utility service equipment at building A.

Not saying your incorrect just need to read 690 and 705 again

Good point, will do. There is tons of phenolic engraved labelling planned I was not even getting into that.....