Medium Voltage Feeder Through a Building

[msteiner]

I'm proposing to route a 13.2kV feeder through the ceiling of one building to serve another. I can't find any code section prohibiting this, or requiring a disconnecting means where it enters the first building. Anything I should be aware of?

 

[jusme123]

...make sure one of the exceptions in 225.32 is applicable to your situation

 

[petersonra]

I wonder if he really meant the feeder was coming out of the first building through its ceiling to feed the second building. In that case it is neither passing through or feeding the first building.

 

[msteiner]

I wonder if he really meant the feeder was coming out of the first building through its ceiling to feed the second building. In that case it is neither passing through or feeding the first building.

No, the feed is coming from elsewhere, stubbing up from below grade, penetrating building A, passing through building A, then feeding an outdoor padmount xfmr that serves building B.

 

[msteiner]

...make sure one of the exceptions in 225.32 is applicable to your situation

225.32 is a paragraph within Part II entitled "Buildings or Other Structures Supplied by a Feeder(s) or Branch Circuit(s)." Since the MV feeder is passing through the building, rather than being "supplied by" the feeder, my interpretation is that this section doesn't apply, and a disconnecting means isn't required for the pass-through.

 

[petersonra]

225.32 is a paragraph within Part II entitled "Buildings or Other Structures Supplied by a Feeder(s) or Branch Circuit(s)." Since the MV feeder is passing through the building, rather than being "supplied by" the feeder, my interpretation is that this section doesn't apply, and a disconnecting means isn't required for the pass-through.

225.31 Disconnecting Means. Means shall be provided
for disconnecting all ungrounded conductors that supply or
pass through the building or structure.

I don't believe that the title of a section is actually considered to restrict its application.

 

[Bugman1400]

What code are you guys referencing....NEC?

 

[iwire]

225.32 is a paragraph within Part II entitled "Buildings or Other Structures Supplied by a Feeder(s) or Branch Circuit(s)." Since the MV feeder is passing through the building, rather than being "supplied by" the feeder, my interpretation is that this section doesn't apply, and a disconnecting means isn't required for the pass-through.

225.32 applies.

 

[iwire]

What code are you guys referencing....NEC?

Yes

 

[Bugman1400]

Yes

I thought NEC only applied to 600 volts or less. Doesn't NESC apply to MV applications? Please correct me.

 

[iwire]

I thought NEC only applied to 600 volts or less. Doesn't NESC apply to MV applications? Please correct me.

The NEC applies to any voltage that is part of a premise wiring. There are many sections specifically for systems over 600 volts.

That said the NEC does not do a great job with it and using the NESC as a back up would be wise.

 

[Smart $]

The following applies...

225.31 Disconnecting Means. Means shall be provided
for disconnecting all ungrounded conductors that supply or
pass through the building or structure.

 

[Sahib]

I'm proposing to route a 13.2kV feeder through the ceiling of one building to serve another. I can't find any code section prohibiting this, or requiring a disconnecting means where it enters the first building. FAnything I should be aware of?

If the cable through ceiling is under concrete cover of suitable depth, then it is considered outside building and disconnecting means requirement will not apply.

 

[Smart $]

If the cable through ceiling is under concrete cover of suitable depth, then it is considered outside building and disconnecting means requirement will not apply.

It is impossible to have a cable through ceiling that has concrete cover (underground). Concrete encasement above grade is considered outside for service conductors, but I do not see anything which permits such for feeder conductors

 

[Sahib]

It is impossible to have a cable through ceiling that has concrete cover (underground). Concrete encasement above grade is considered outside for service conductors, but I do not see anything which permits such for feeder conductors

Concrete cover is there for ceiling slab also. Feeder cable through the ceiling of first building is for the second building only and so disconnecting means on the first building for that cable is not required. In this regard Bob comment at post3 is relevant.

 

[iwire]

If the cable through ceiling is under concrete cover of suitable depth, then it is considered outside building and disconnecting means requirement will not apply.

For the OPs feeder this is false information.

 

[iwire]

It is impossible to have a cable through ceiling that has concrete cover (underground). Concrete encasement above grade is considered outside for service conductors, but I do not see anything which permits such for feeder conductors

The rules of 230.6 are allowed as far as the feeders distance to the disconnecting means. Once beyond the disconnecting means I agree with you.

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.

 

[mbrooke]

Its doable, done all the time in high rise buildings were a substation is mounted on the roof or in the MER to feed the building itself or parts of it.

 

[Sahib]

Its doable, done all the time in high rise buildings were a substation is mounted on the roof or in the MER to feed the building itself or parts of it.

That is done beginning at the construction stage of the building itself and not after the building construction is over. In OP case if he runs the cable actually outside the first building, no need for disconnecting means on the first building. What do you think?

 

[Smart $]

The rules of 230.6 are allowed as far as the feeders distance to the disconnecting means. Once beyond the disconnecting means I agree with you.

And the ultimate point he must install a disconnecting means at the first building to have the conductors pass through it.