maximun # of disconnects?

[pierre]

Re: maximun # of disconnects?

Don

230.40 ex #1. A building with one or more than one occupancy shall be permitted to have one set of service entrance conductors for each service of different characteristics, as defined in 230.2(D), run to each occupancy or group of occupancies.

I do not see how the several to many apartments would require different characteristics for the service.

The individual apartments most likely will have meters with feeder conductors, not service conductors. I cannot see that many service disconnects permitted in a building of any kind, it would be a nightmare for the fire department.

For really large apartment buildings that may have ground floor stores, I can see more service disconnects based on different characteristics.

Pierre

 

[don_resqcapt19]

Re: maximun # of disconnects?

Pierre,
Exception #1 to 230.40 only applies to a single service drop or lateral. How do you get services of different characteristics from a common service dropm or lateral?
I read the exception as saying that each occupancy can have a set of service entrance conductors for each type of service characteristic that that occupancy requires. In the case of dwelling units, only one characteristic is required, so one set of service entrance conductors is permitted for each unit. Every set of service entrance conductors is permitted to have up to six disconnects. In this application, there would only be one disconnect for each meter and, as you stated, a feeder to the dwelling unit panel, but even with one service disconnect for each unit, there are more than 6 service disconencts.
Don

 

[pierre]

Re: maximun # of disconnects?

I may not understand your post so I will say this.

The NEC generally permits one service (with up to 6 disconnects) to a 'building', with some exceptions. The apartments in the 'building' are dwelling units, but do not require their own 'service'. The building requires a service, but not the apartments. Lets say this multifamily building has more than 6 dwelling units. The NEC does not permit each unit to have it's own service if there will be more than 6 disconnects involved. So the service will be sized according to Article 220 ( with up to 6 disconnects) and then there can be as many feeder disconnects to the apartments as necessary.

There is no requirement that individual dwelling units (apartments)in the same building have to have their own service.

Pierre

 

[david]

Re: maximun # of disconnects?

I see now that the 72 apartments are hypothetical in Mr. Hanky?s post.

He has two service risers feeding two groups of 6 meter/disconnects. I agree Don is correct in saying that this is one service. If these 12 meter/disconnects are in one location than you need to have disconnects ahead of the six-gang meter/disconnects to limit the service disconnects two six in any one location.

How ever if these service risers are in two different locations than you have two separate services. You need special permission for this set up. You still will limit the service disconnects to the max of six in any one location and you need to apply
230.2 Number of Services.
(E) Identification.

Don
I am reading the post and seeing service risers and thinking service laterals. You seem to be reading it as one service drop and two service entrances.

If Don is correct and this is one service drop tapped by two service entrances. This is one service and you do not need special permission for this. If the 12 meters/disconnects are grouped at one location than you need to limit the service disconnects two the max of six.
230.40 Number of Service-Entrance Conductor Sets.
Exception No. 2:

If the group of six meter/disconnects are at two separate location, this is one service with two service entrances and is allowed according to
230.40 Number of Service-Entrance Conductor Sets.
Exception No. 1:

Hypothetical you could have one service drop tapped by 72 separate service entrances run to separate location (apartment units) according to
230.40 Number of Service-Entrance Conductor Sets.
Exception No. 1:
As long as the service entrance conductors can be defined as on the exterior of the building and disconnected as soon as the make entrance into the individual apartments.

 

[hurk27]

Re: maximun # of disconnects?

David I have seen this done on a few apartments where the service drop was made to a 16 gain meter pack then SEU to each 60 amp service panel just in side each apartment with less than 6 circuit breakers each. This setup had no disconects ahead of the meters or on the meters. the only disconects were the branch circuit breakers in each apartment. and the only way for the disconection of the services was by these breakers or by pulling the meters. I was told by the state AHJ that this was allowed as each apartment was served by it's own service entrance cable. this was about 10 years ago.

 

[david]

Re: maximun # of disconnects?

Hurk,

This is where this area becomes gray for me. Since the code only addresses grouping of disconnects I guess if there are no disconnects at these meter banks and the banks are on the exterior of the building this would be allowed.

 

[don_resqcapt19]

Re: maximun # of disconnects?

Hurk,
How is 230.70(A)(1) satisified in the 16 unit buildings. Is the SEU run exterior until it gets to each apartment?
Don

 

[hurk27]

Re: maximun # of disconnects?

Yes Don It was this resone that we were called. The owner wanted to reside the complex and didn't know what to do with the SEU running down the back side of the units from the meters. And wanted a price on up gradeing the service to allow for 100 amps per unit. After I explained what was requires to eliminate the SEU and to rerun the SEC's to each apartment he didn't like what it was going to cost so I never went back.

 

[pierre]

Re: maximun # of disconnects?

Wayne

You want to bet that those cables are covered. It would be interesting if you could see if they resided and did anything with the cable

Pierre

 

[wolfman56]

Re: maximun # of disconnects?

I'm designing a system right now that is just like this. A 5000' per floor 2 story building. With 2 individually metered retail stores on the first floor and the owner wants the 8 apartments on the second to be individually metered also, along with a house meter for the hallway areas! A total of 11 meters. I wanted a separate service for the apartments, the AHJ said no. In order to keep the existing service the owner is now creating a 2 hour barrier between the first and second floors. Then the second becomes a separate occupancy and can now have it's own service. Which will have to have a main disconnect because the 9 individual meter main combos exceeds the 6 switch limit. As far as the discussion on how many switches per service it was put to me this way. If you were a fireman responding to a fire how many switches would you want to find and throw to shut down the building? Thus 6 is max.

 

[charlie]

Re: maximun # of disconnects?

The way it is interpreted in Indiana is a single service drop or lateral may service as many sets of service entrance conductors as their are occupancies. Each occupancy may have as many as six disconnects in one location. If they choose to have their service disconnects at the location of the meters (we require the meters to be grouped close to the termination point of the service drop or lateral), they are limited to six at that location.

We install a lot of strip centers where we hit the building in a junction cabinet with bus bars for termination. From there, the EC will run down the back of the building both ways to a maximum of eight occupancies. Since the structure is not entered until the service entrance conductors get to the occupancy, six service disconnecting means are permitted.

BTW, the auto-signature will display on the first post of the thread but not after that. There are exceptions programmed in but the intent is to save space.

 

[mrhanky]

Re: maximun # of disconnects?

The 2-6 gang meter bases are right next to each other on the same wall. The service is overhead. I was going to come out of each 200 amp disconnect to attach to 1 service drop. Now after reading some of your replies am I to underdstand that I dont need the 2-200 amp disconnects? Thanks.



_____________ ____________
{_O_O_O_O_O_O_}--200Amp 200Amp--{O_O_O_O_O_O_}
disco disco

 

[bigjohn67]

Re: maximun # of disconnects?

You can cut and slice it any way you want. An apartment building can have as many services as you want. It has to be disconnected by 6 or less switches. An apartment complex is separated by buildings (fire walls, block walls) but appear to be connected as one complex. Each "building" must have 6 or less disconnects.
why is this so hard to understand.
If you have one "building" that has 12 units. Usually you have 2 meter banks, 1 disconnect for each, 2 disconnects which satifies the rule.
Now you have 12 "buildings", thats 144 units.
Still the same 2 main disconnects per "building"
They may be 800 amps a piece but it still saticfies the rule. Total you have 24 main disconnects but still 2 per "building"

 

[david]

Re: maximun # of disconnects?

Big John

An apartment building can have as many service entrances as you design. How ever it can only have one service unless you get special permission from the authority.

 

[russ]

Re: maximun # of disconnects?

My interpretation of article 230 is that you are only allowed six switches or circuit breakers to control the service entrance conductors.
Just because there are several meters involved, does not allow this service to be considered to be consisting of more than one set of service entrance conductors.
If someone were to install six 6 circuit panels and not put a main (or six mains total), in front of each panel, I could not let it be energized.
To me it violates 230.71

Service. The conductors and equipment for delivering energy from the electricity supply system to the wiring system on the premises
served.

Service Cable. Service conductors made up in the form of a cable.

Service Conductors. The conductors from the service point to the service disconnecting means.

Service Drop. The overhead service conductors from the last pole or other aerial support to and including the splices, if any, connecting to the service-entrance conductors at the building or other structure.

Service-Entrance Conductors, Overhead System. The service conductors between the terminals of the service equipment and a point usually outside the building, clear of building walls, where joined by tap or splice to the service drop.

Service-Entrance Conductors, Underground System. The service conductors between the terminals of the service equipment and the point of connection to the service lateral.

FPN: Where service equipment is located outside the building walls, there may be no service-entrance conductors, or they may be entirely
outside the building.

Service Equipment. The necessary equipment, usually consisting of a circuit breaker(s) or switch(es) and fuse(s), and their accessories, connected to the load end of service conductors to a building or other structure, or an otherwise designated area, and intended to constitute the main control and cutoff of the supply.

 

[charlie]

Re: maximun # of disconnects?

Big John, let me give you an answer you can take to the bank. Ask the AHJ! The reason I jumped in was to indicate that the Code is interpreted in a different manner in different areas. Different areas also adopt the Code with different amendments. BTW, did I say ah gotta ax thu AHJ? Remember, the inspector is always correct.

 

[iwire]

Re: maximun # of disconnects?

Charlie's answer is of course the only one that is bankable, talk to the local inspector/AHJ before you start something like this.

Russ I tried to send you a PM but you must have it shut off.

 

[russ]

Re: maximun # of disconnects?

Bob:

I see the two service entrances your talking about, in the 99 handbook it's figure 230.2c.

I could see this type of service being allowed on some occasion. All the panels would still require mains.

Russ

PS. I changed a few things in my settings

[ November 30, 2003, 12:47 PM: Message edited by: russ ]

 

[bigjohn67]

Re: maximun # of disconnects?

Please read my post. I said "as many services". I did not say "service drops".
Let me re-phrase it.

You must disconnect all power to a building that is fed with one service drop with 6 or less motions of the hand. Cut it any way you wish.
6 200 amp mains feeding 6 apartments
1 800 amp main feeding 6 apartments, then you can have 6 -800 amp mains if their were 36 apartments.

Or you can have 1-800 amp main and 5-200 amp mains. The 800 feeds 6- 200 amp mains. But still this is only 6 motions to cut power.

 

[iwire]

Re: maximun # of disconnects?

John that is just not how it is everywhere.

It may be in the area you work the only way that the local AHJ allows.

Another example is in the 2002 handbook is Exhibit 230.9 One service lateral supplying two sets of service-entrance conductors with not more than six disconnects grouped in one location.

This one shows a total of eight disconnects at one building.