If you feed an apartment complex with a 400 amp service and have 2 service risers with 2/0 feeding 2 - 6 gang meter bases wouldnt this be a total of 12 meters/service disconnects? An inspector told me its not and that I could have 6 disconnects per meter base for a total of 72 disconnects at the apartment complex (12X6=72). Does that sound right to any one? I thought I would need 2 - 200 amp disconnects ahead of each 6 gang meter base? Thanks for any help.
maximun # of disconnects?
- Thread starter mrhanky
- Start date
- Status
Re: maximun # of disconnects?
Simply put. If you can disconnect all power to the building with no more than 6 motions of the hand, this is acceptable.
In other words you can have 6 banks of 6 meters, as long as you have a main in front of each 6 meters you are ok. As long as you do not go over the 6 hand rule you are ok. these disconnects must all be located in the same location. there is an exception, but it deals more with the number of drops to a building.
Simply put. If you can disconnect all power to the building with no more than 6 motions of the hand, this is acceptable.
In other words you can have 6 banks of 6 meters, as long as you have a main in front of each 6 meters you are ok. As long as you do not go over the 6 hand rule you are ok. these disconnects must all be located in the same location. there is an exception, but it deals more with the number of drops to a building.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: maximun # of disconnects?
Big john 230.71 allows for each set of service-entrance conductors permitted by 230.40, to have 6 means of disconect. 230.40 Exception #4 allows for more than one set of service entrance conductors on a a multifamily dwelling. so from what I get is 6 means of disconect per set of service-entrance conductors. But I'll leave this up to debate by others.
Big john 230.71 allows for each set of service-entrance conductors permitted by 230.40, to have 6 means of disconect. 230.40 Exception #4 allows for more than one set of service entrance conductors on a a multifamily dwelling. so from what I get is 6 means of disconect per set of service-entrance conductors. But I'll leave this up to debate by others.
Re: maximun # of disconnects?
I have always been confused on this issue. I have the NEC handbook, and the diagrams they show seem to raise more questions than answers. Take exhibit 230.4 for example. It shows one building (with 2 occupancies - but I'm not sure what the definition of an "occupancy" is exactly) with 2 sets of service entrance conductors supplying two groups of disconnects in different locations. Why is this allowed in this case? Figures 230.12 and 230.13 also show disconnects at separate locations.
Can anyone explain exactly when this would be allowed?
Steve
I have always been confused on this issue. I have the NEC handbook, and the diagrams they show seem to raise more questions than answers. Take exhibit 230.4 for example. It shows one building (with 2 occupancies - but I'm not sure what the definition of an "occupancy" is exactly) with 2 sets of service entrance conductors supplying two groups of disconnects in different locations. Why is this allowed in this case? Figures 230.12 and 230.13 also show disconnects at separate locations.
Can anyone explain exactly when this would be allowed?
Steve
charlie
Senior Member
- Location
- Indianapolis
Re: maximun # of disconnects?
From Merriam-Webster's Unabridged Dictionary
Main Entry: oc-cu-pan-cy
Function: noun
Inflected Form:-es
Etymology: occupant + -cy
1a: the taking and holding possession of real property under a lease or tenancy at will b: the act of taking possession of something that has no owner (as a waif or derelict) and thus acquiring title to it
2a: the act of becoming an occupant or the condition of being an occupant (between successive human occupancies, the caves were often used by wild animals? R.W.Murray) (the essential quality of his existence consists in his occupancy of this world of symbols and ideas? L.A.White) (ten years of uninterrupted occupancy of this position) b: the condition of being occupied (though the village site showed two levels of occupancy, the temple mound showed three? American Guide Series: Tennessee) (ghetto-slums which were both substandard and homogeneous in their occupancy? Charles Abrams)
3: the particular use or type of use to which property (as a building or part of a building) is put (residential occupancy) (industrial occupancy) (storage occupancy)
4: an occupied building or part of a building (as an apartment or office)
From Merriam-Webster's Unabridged Dictionary
Main Entry: oc-cu-pan-cy
Function: noun
Inflected Form:-es
Etymology: occupant + -cy
1a: the taking and holding possession of real property under a lease or tenancy at will b: the act of taking possession of something that has no owner (as a waif or derelict) and thus acquiring title to it
2a: the act of becoming an occupant or the condition of being an occupant (between successive human occupancies, the caves were often used by wild animals? R.W.Murray) (the essential quality of his existence consists in his occupancy of this world of symbols and ideas? L.A.White) (ten years of uninterrupted occupancy of this position) b: the condition of being occupied (though the village site showed two levels of occupancy, the temple mound showed three? American Guide Series: Tennessee) (ghetto-slums which were both substandard and homogeneous in their occupancy? Charles Abrams)
3: the particular use or type of use to which property (as a building or part of a building) is put (residential occupancy) (industrial occupancy) (storage occupancy)
4: an occupied building or part of a building (as an apartment or office)
Re: maximun # of disconnects?
OK Charlie, I guess I should have been more specific when I said I didn't know what an occupancy was
I have heard of the word before
If I take the definitions in the dictionary; I occupy my cubicle at work, and my coworker occupies his cubicle. Therefore, they are separate occupancies. Per exhibit 230.4, I can have 6 disconnects grouped at my cubicle, and my coworker can have another 6 disconnects grouped at his cubicle.
We all know something is wrong with the logic above, and I am assuming the NEC means something more by the phrase "separate occupancies".
Steve
OK Charlie, I guess I should have been more specific when I said I didn't know what an occupancy was
I have heard of the word before If I take the definitions in the dictionary; I occupy my cubicle at work, and my coworker occupies his cubicle. Therefore, they are separate occupancies. Per exhibit 230.4, I can have 6 disconnects grouped at my cubicle, and my coworker can have another 6 disconnects grouped at his cubicle.
We all know something is wrong with the logic above, and I am assuming the NEC means something more by the phrase "separate occupancies".
Steve
Re: maximun # of disconnects?
Also, the only way a multiple occupancy apartment building is allowed to have more than one service is by SPECIAL PERMISSION. (not counting the fire pump). Special permission requires written consent from the AHJ. It is clear from the pictures in the handbook that an apartment building is a multiple occupancy building. Each apartment is an occupancy.(dwelling unit). The same way a strip mall has multiple occupancies. (merchantile and maybe business too)
Each service location is allowed to have up to six disconnects. (230.71) grouped together (230.72).
Also, the only way a multiple occupancy apartment building is allowed to have more than one service is by SPECIAL PERMISSION. (not counting the fire pump). Special permission requires written consent from the AHJ. It is clear from the pictures in the handbook that an apartment building is a multiple occupancy building. Each apartment is an occupancy.(dwelling unit). The same way a strip mall has multiple occupancies. (merchantile and maybe business too)
Each service location is allowed to have up to six disconnects. (230.71) grouped together (230.72).
Re: maximun # of disconnects?
Single buildings with multiple apartments must have more than one service.
Reasons; A typical 32 unit apartment building. 16 up 16 down.
The transformer would be huge for one service.
The available fault current would exceed the service ratings.
The feeder lengths would require big conduit and wire.
Each apartment requires a main switch at the service entrance. This would be a minimum of six services to the building. There will be a firewall between groups of six apartments, making them a separate building by definition.
Most high rise apartment buildings are supplied by a main bus duct with a service transformer at each floor. The complex may be considered as one building but the apartments are essentially a separate service with six main switches in the panelboard.
This is why I maintain the service point is at the loadcenter of a premises wiring system. It is where the utility power electrically connects to the premises distribution system.
[ November 25, 2003, 04:15 PM: Message edited by: bennie ]
Single buildings with multiple apartments must have more than one service.
Reasons; A typical 32 unit apartment building. 16 up 16 down.
The transformer would be huge for one service.
The available fault current would exceed the service ratings.
The feeder lengths would require big conduit and wire.
Each apartment requires a main switch at the service entrance. This would be a minimum of six services to the building. There will be a firewall between groups of six apartments, making them a separate building by definition.
Most high rise apartment buildings are supplied by a main bus duct with a service transformer at each floor. The complex may be considered as one building but the apartments are essentially a separate service with six main switches in the panelboard.
This is why I maintain the service point is at the loadcenter of a premises wiring system. It is where the utility power electrically connects to the premises distribution system.
[ November 25, 2003, 04:15 PM: Message edited by: bennie ]
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: maximun # of disconnects?
Early Dean where in 230.40 does it say by Special permission?
Early Dean where in 230.40 does it say by Special permission?
- Location
- Massachusetts
Re: maximun # of disconnects?
Hurk I think you may be looking at the wrong article.
Try 230.2(B) or 230.2(C)(3)
Hurk I think you may be looking at the wrong article.
Try 230.2(B) or 230.2(C)(3)
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: maximun # of disconnects?
Iwire
I think there is a differance between a multifamily dwelling and Multiple-occupancy buildings or why the differant wording?
look at the exceptions to 230.40 #1 and #4 why the two exceptions if they are the same?
I'm thinking Multiple-occupancy buildings is like a strip mall or offices or the like but multifamily dwelling is defintly where people reside, sleep cook, Etc...
Maybe I'm wrong on this thinking but this was the way it was told to me
Iwire
I think there is a differance between a multifamily dwelling and Multiple-occupancy buildings or why the differant wording?
look at the exceptions to 230.40 #1 and #4 why the two exceptions if they are the same?
I'm thinking Multiple-occupancy buildings is like a strip mall or offices or the like but multifamily dwelling is defintly where people reside, sleep cook, Etc...
Maybe I'm wrong on this thinking but this was the way it was told to me
- Location
- Massachusetts
Re: maximun # of disconnects?
Well I know I am confused.
And to all, feel free to call me Bob.
[ November 25, 2003, 08:48 PM: Message edited by: iwire ]
Well I know I am confused.
And to all, feel free to call me Bob.
[ November 25, 2003, 08:48 PM: Message edited by: iwire ]
G
Guest
Guest
Re: maximun # of disconnects?
Hey Bob,
Have you ever wondered why sometimes your "signature" sticks and sometimes it does not?
Let's see if my signature sticks on this one.
Hey Bob,
Have you ever wondered why sometimes your "signature" sticks and sometimes it does not?
Let's see if my signature sticks on this one.
david
Senior Member
- Location
- Pennsylvania
Re: maximun # of disconnects?
MR Hanky.
I need to make a couple of assumptions to take a stab at an answer here.
First I will assume this apartment complex is all under one roof ( one building).
Second if I understand correctly, This one building is being supplied by 12ea. 400 amp services
In accordance with: 230.2 Number of Services.
(B) Special Occupancies. By special permission, additional services shall be permitted for the following:
(2) A single building or other structure sufficiently large to make two or more services necessary
I agree with you for this to be code compliant, I think you have two choices here. Supply the building with 24 services the total of six disconnects grouped at any one location. Or add the two 200 amp disconnects as you have stated at the group of 12 meter/disconnects.
As stated by others 230.2(B) requires special permission from the authority with ether of these two options
MR Hanky.
I need to make a couple of assumptions to take a stab at an answer here.
First I will assume this apartment complex is all under one roof ( one building).
Second if I understand correctly, This one building is being supplied by 12ea. 400 amp services
In accordance with: 230.2 Number of Services.
(B) Special Occupancies. By special permission, additional services shall be permitted for the following:
(2) A single building or other structure sufficiently large to make two or more services necessary
I agree with you for this to be code compliant, I think you have two choices here. Supply the building with 24 services the total of six disconnects grouped at any one location. Or add the two 200 amp disconnects as you have stated at the group of 12 meter/disconnects.
As stated by others 230.2(B) requires special permission from the authority with ether of these two options
pierre
Senior Member
- Location
- Westchester County, New York
Re: maximun # of disconnects?
There is a lot of confusion with the terms being used for 230.2, occupancy being one of them.
Because of the multiple use of the word by dictionary definition, the only way to resolve how the CMP meant for the term to be used is to contact the NFPA. But I will take a stab at it myself.
230.2(B) Special Occupancies.
This section is not as liberal as many think it is. First, special permission is required. Second the restrictions are intermingled among other sections, this section does not stand alone.
The last sentence in 230.2 is very specific and overlooked a lot. The exceptions to 230.40 are quite restrictive and do not give as much relief as most would like to have.
Then we have the term 'occupancy', which is not quite spelled out in the NEC, so it becomes an interpretation in the field. What really needs to be done is get an interpretation from the NFPA.
My take is that occupancy means different types of tenants such as different offices, stores, etc... where the office might need 3 phase 208v and the other occupancy in the building may need 3 phase 480v, therefore two different services (230.40 Exception 1).
I do a lot of work in multifamily buildings, and the meter banks are fed by different feeders, not different services. There is one main ahead that could be feeding either different banks of disconnects (which feed different meterbanks) or directly feeding the meterbanks.
230.40 Number of Service-Entrance Conductor Sets. Each service drop or lateral shall supply only one set of service-entrance conductors.
There are exceptions, but they are very specific - don't forget how the last sentence of 230.2 affects exception # 2.
Otherwise I do not see how a multifamily dwelling can have a separate set of service entrance conductors serving each meter bank, with its own set of disconnects. The only reason I can see for this would be the space requirement, where there are many apartments and not enough space in each meter room. Then 'special' permission is required.
Pierre
There is a lot of confusion with the terms being used for 230.2, occupancy being one of them.
Because of the multiple use of the word by dictionary definition, the only way to resolve how the CMP meant for the term to be used is to contact the NFPA. But I will take a stab at it myself.
230.2(B) Special Occupancies.
This section is not as liberal as many think it is. First, special permission is required. Second the restrictions are intermingled among other sections, this section does not stand alone.
The last sentence in 230.2 is very specific and overlooked a lot. The exceptions to 230.40 are quite restrictive and do not give as much relief as most would like to have.
Then we have the term 'occupancy', which is not quite spelled out in the NEC, so it becomes an interpretation in the field. What really needs to be done is get an interpretation from the NFPA.
My take is that occupancy means different types of tenants such as different offices, stores, etc... where the office might need 3 phase 208v and the other occupancy in the building may need 3 phase 480v, therefore two different services (230.40 Exception 1).
I do a lot of work in multifamily buildings, and the meter banks are fed by different feeders, not different services. There is one main ahead that could be feeding either different banks of disconnects (which feed different meterbanks) or directly feeding the meterbanks.
230.40 Number of Service-Entrance Conductor Sets. Each service drop or lateral shall supply only one set of service-entrance conductors.
There are exceptions, but they are very specific - don't forget how the last sentence of 230.2 affects exception # 2.
Otherwise I do not see how a multifamily dwelling can have a separate set of service entrance conductors serving each meter bank, with its own set of disconnects. The only reason I can see for this would be the space requirement, where there are many apartments and not enough space in each meter room. Then 'special' permission is required.
Pierre
- Location
- Illinois
- Occupation
- retired electrician
Re: maximun # of disconnects?
In my opinion this installation only has a single service so 230.2 does not enter into the discussion. It is also my opinion that each utility customer (occupancy) is permitted to have up to 6 means of disconnect on their service entrance cables per 230.40 Ex. #1. Each occupancy (utilty customer) is permitted by this exception to have six disconnects for each class of service that is provided to that customer. In this case only one class of service is provided to each customer so a total of 72 disconnects are permitted by the code.
Don
In my opinion this installation only has a single service so 230.2 does not enter into the discussion. It is also my opinion that each utility customer (occupancy) is permitted to have up to 6 means of disconnect on their service entrance cables per 230.40 Ex. #1. Each occupancy (utilty customer) is permitted by this exception to have six disconnects for each class of service that is provided to that customer. In this case only one class of service is provided to each customer so a total of 72 disconnects are permitted by the code.
Don
david
Senior Member
- Location
- Pennsylvania
Re: maximun # of disconnects?
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). For the purpose of 230.40, Exception No. 2 only, underground sets of conductors, 1/0 AWG and larger, running to the same location and connected together at their supply end but not connected together at their load end shall be considered to be supplying one service.
Don:
?running to the same location?, Mr. Hanky never indicated that the service laterals ended in the same location and because he talked of groups of 12 service/disconnects I assume there are 12 separate locations.
Even if the laterals are run to the same location Am I correct in thinking we are both saying the service disconnects needs to be limited to a total of six for any one group.
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). For the purpose of 230.40, Exception No. 2 only, underground sets of conductors, 1/0 AWG and larger, running to the same location and connected together at their supply end but not connected together at their load end shall be considered to be supplying one service.
Don:
?running to the same location?, Mr. Hanky never indicated that the service laterals ended in the same location and because he talked of groups of 12 service/disconnects I assume there are 12 separate locations.
Even if the laterals are run to the same location Am I correct in thinking we are both saying the service disconnects needs to be limited to a total of six for any one group.
- Location
- Illinois
- Occupation
- retired electrician
Re: maximun # of disconnects?
David,
I'm saying that if you have one service drop, then each meter supplied by that drop can have up to six disconnects.
Don
David,
I'm saying that if you have one service drop, then each meter supplied by that drop can have up to six disconnects.
Don
- Status