1984 building with 9 disconnects

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tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
I have been asked to look at a multi occupancy (multifamily) 8 unit building built and inspected in 1985 to see if it meets at minimum the 1984 NEC (that was in effect). Now I know lots have changed since then but the requirement for not more than 6 service disconnects goes way back.
The building has one mast with a set of parallel conductors that connects to one utility drop. The mast terminates in a tap box. Off the tap box is a typical modular meter center with 9 meter/mains. Each meter main is rated 100A and has a 80A breaker installed to feed each dwelling unit.
Is this a service with 9 disconnects?
Or are the bus bars service 'sets' and each of the mains a 'service' to a 'building' with one service disconnect? All of course at one service disconnect location.
Was this allowable back then and is it allowed now in the 2014 NEC?
I am interested in your thoughts and opinions.


The closest old code book I have handy is the '81
The '81 had an exception (3) to 230-2 number of services for multi-occupancy buildings, very similar to the 2014 NEC 230.40 ex 1
Thanks in advance
 

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iwire

Moderator
Staff member
Location
Massachusetts
I was installing stuff like this in 84 and that is nine service disconnects.

We would have used a main breaker section for this instead of a tap box.

You might still be able to get a main breaker section to replace the tap box if they want it fixed.
 

kwired

Electron manager
Location
NE Nebraska
The '81 had an exception (3) to 230-2 number of services for multi-occupancy buildings, very similar to the 2014 NEC 230.40 ex 1

Don't know exact wording that may have been in 81 but IMO what is intended in 14 is that no more then six disconnects be grouped at one location, for a multi occupant situation I think the intention was that each occupant has a service disconnect at their occupancy, not that you can group all nine at one location. Typically building codes will require fire ratings between each occupancy that are effective enough to consider each occupancy as a separate building or equivalent in such situations.
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
I have been asked to look at a multi occupancy (multifamily) 8 unit building built and inspected in 1985 to see if it meets at minimum the 1984 NEC (that was in effect). Now I know lots have changed since then but the requirement for not more than 6 service disconnects goes way back.

Back in the early 80's, the AHJ, in Marquette MI, agreed to let us apply this interpretation for a housing complex. As part of the agreement, the AHJ clarified their rules on multi-metering, to prevent future installations of >6 meters without a single main on each 'utility drop'.
 

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
I was installing stuff like this in 84 and that is nine service disconnects.

We would have used a main breaker section for this instead of a tap box.

You might still be able to get a main breaker section to replace the tap box if they want it fixed.

Thank you for the information. Thats good to know about the main breaker section.
It could be the utility does not or did not allow mains before the metering.

If it meets the '84 code which it appears it does, no need to fix it at this time.
The inspection was for the owners insurance company.
Thanks again.
 

Sierrasparky

Senior Member
Location
USA
Occupation
Electrician ,contractor
The closest old code book I have handy is the '81
The '81 had an exception (3) to 230-2 number of services for multi-occupancy buildings, very similar to the 2014 NEC 230.40 ex 1
Thanks in advance

How does that exception work in the 2014. I see that is all about service wires and not disconnects?
 

david

Senior Member
Location
Pennsylvania
Thank you for the information. Thats good to know about the main breaker section.
It could be the utility does not or did not allow mains before the metering.

If it meets the '84 code which it appears it does, no need to fix it at this time.
The inspection was for the owners insurance company.
Thanks again.

where did any body say it met the code in 1984
 
Don't know exact wording that may have been in 81 but IMO what is intended in 14 is that no more then six disconnects be grouped at one location, for a multi occupant situation I think the intention was that each occupant has a service disconnect at their occupancy, not that you can group all nine at one location. Typically building codes will require fire ratings between each occupancy that are effective enough to consider each occupancy as a separate building or equivalent in such situations.

I agree with Kwired. I would add that, IMO, use of the term "occupancy" is a little sticky as the NEC doesnt define it so you would have to see what the local definition of such a space is. I dont think "multi-occupancy" is necessarily the same as "multi-family". Here in upsate NY, it is very common and permitted to have, say, a three gang meter socket without disconnects, and a main breaker service panel in each apartment. Often these are old apartments with no specific fire separation between the apartments.
 

mwm1752

Senior Member
Location
Aspen, Colo
NEC 1984 is very similar to NEC 2014 in 230.71 & 72 -- The picture shows a single service with > 6 disconnecting means -- 230.2 is for additional services which could have up to 6 disconnecting means for each service -- unless 3 of the disconnects are (1) Power monitoring equipment, (2) Surge-protective device(s), (3) Control circuit of the ground-fault protection system, (4) Power-operable service disconnecting means can't see it being a legal install even in 1984
Might be due to interpretation of NEC language in 1985 - we all know how cut & dry it is today:happysad:.
 

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
If I read these four (1981 NEC) items correctly and if they were still true in '84:
  1. 230-2 Number of Services. A building or structure served shall be supplied by only one service. Where more than one service is permitted by any of the following exceptions, a permanent plaque or directory shall be installed at each service drop or lateral or at each service-equipment location denoting all other services on or in that building or structure and the area served by each
    Then there is the
    Exception 3: Multiple-Occupancy Buildings. (b) Buildings of multiple occupancy shall be permitted to have two or more separate sets of service entrance conductors which are tapped from one service drop or lateral
    ( no special permission needed back then )
  2. The definition of "building" includes firewall separated spaces.
  3. If the meter pack buss bar can be considered "service entrance conductors".
  4. 230-71 (a) General. The service disconnecting means for each service or each set of service-entrance conductors permitted by section 230-2, Exception No. 3b. shall consist of not more than six switches or six circuit breakers mounted in a single enclosure, in a group of enclosures or in a switchboard.
What I come up with is the tap box supplies 9 "sets" of service entrance conductors each set has one main breaker (but is allowed up to 6). Each main is a "service disconnect" to a "building".
All references are based on the 1981 NEC
 

iwire

Moderator
Staff member
Location
Massachusetts
What I come up with is the tap box supplies 9 "sets" of service entrance conductors each set has one main breaker (but is allowed up to 6). Each main is a "service disconnect" to a "building".
All references are based on the 1981 NEC

The tap box does not have 9 separate connections for each 'set'.
 

iwire

Moderator
Staff member
Location
Massachusetts
There is a separate 'tap' to each main.

I disagree that you can choose to call the internal busing service conductors.

You have one set of service conductors terminating in the tap box.


The AHJ may have allowed it, but I do not see it as NEC compliant.
 

kwired

Electron manager
Location
NE Nebraska
If I read these four (1981 NEC) items correctly and if they were still true in '84:

  1. Then there is the ( no special permission needed back then )
  2. The definition of "building" includes firewall separated spaces.
  3. If the meter pack buss bar can be considered "service entrance conductors".
What I come up with is the tap box supplies 9 "sets" of service entrance conductors each set has one main breaker (but is allowed up to 6). Each main is a "service disconnect" to a "building".
All references are based on the 1981 NEC

So you may effectively have 9 "buildings" but all your service disconnecting means are on one of them. I think the intention of the rule is that each one have it's own service disconnect at each "building"
 

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
I disagree that you can choose to call the internal busing service conductors.

You have one set of service conductors terminating in the tap box.


The AHJ may have allowed it, but I do not see it as NEC compliant.

I am looking at (NEC 1981) Tap rules
240-21 Location in Circuit. An overcurrent device shall be connected at the point where the conductor to be protected receives its supply. .... Exception No.4 Service Conductors. For service-entrance conductors where protected in accordance with Section 230-91.
...
230-91 Location. The service overcurrent device shall be an integral part of the service disconnection means or shall be located immediately adjacent thereto
Looks to me like the bus bars in the meter pack are "an integral part" of the meter pack.
So far I don't see a (1981) code provision prohibiting the use of the bus bar as service entrance conductor taps.

kwired said:
So you may effectively have 9 "buildings" but all your service disconnecting means are on one of them. I think the intention of the rule is that each one have it's own service disconnect at each "building"
I thought so too but then 230-90 would include not include:
230-90 Where Required. ..... (c)More than one Building. In a property comprising more than one building under single management, the ungrounded conductors supplying each building served shall be protected by overcurrent devices, which may be located in the building served or in another building on the same property, provided they are accessible to the occupants of the building served
if that was the intent at the time.
That seems to contradict not grouping more than 6 disconnects at one location since each building can have 6 service disconnects.

There are some interesting discussions in the "NEC-TCDA-1983" on a proposal accepted in principal 4-36 by " H. B. Stauffer, NEMA"
NEC-TCDA-1983 said:
follows.
Delete Exception No. 3b. Insert new Section 230-3 t i t l e d :
"230-3. Number of Service Entrance Conductor Sets. Each
service drop or lateral shall supply only one set of
service-entrance conductors.
Exception No. 1. Buildings of multiple occupancy shall be
permitted to have one set of service-entrance conductors run to
each occupancy or to group of occupancies.
.....
SUBSTANTIATION: Section 230-2 has been the most confusing Section
in the Code for years due to the six disconnect rule and by
accepting the proposal, wording for this section and coordinating
wording suggested for Section 230-71(a), sufficient clarification
should be achieved.
PANEL ACTION: Accept in Principle.
Its available on the NFPA website under the 1984 NEC, so they were infact discussing this issue at the time.
I await my 1984 code book in the mail to do my final research.
 

mwm1752

Senior Member
Location
Aspen, Colo
I thought so too but then 230-90 would include not include:

230-90 Where Required. ..... (c)More than one Building. In a property comprising more than one building under single management, the ungrounded conductors supplying each building served shall be protected by overcurrent devices, which may be located in the building served or in another building on the same property, provided they are accessible to the occupants of the building served


if that was the intent at the time.
That seems to contradict not grouping more than 6 disconnects at one location since each building can have 6 service disconnects. Quote per Tortuga


The disconnects have been defined as disconnecting the power to units in a single building - not several buildings -- the disconnecting means for a structure is limited to six switches for each service that serves the structure ( with exceptions as I defined in an earlier post) -- you have a single service to the structure that has 9 disconnecting means for the service -- having a main OCPD for the service prior to the 9 disconnects which disconnect units within the structure would make the install compliant IMO
 

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
The disconnects have been defined as disconnecting the power to units in a single building - not several buildings
Well it could be argued that each unit meets the definition of a building in NEC art 100.
But for purpose of understanding the 1981 NEC I still see
1981 Code 230-2 Exception 3 (b):
Exception 3: Multiple-Occupancy Buildings. (b) Buildings of multiple occupancy shall be permitted to have two or more separate sets of service entrance conductors which are tapped from one service drop or lateral
As allowing a set of "service conductors" to each occupancy.
Thus the building was allowed to have 9 services.
Each can have up to 6 disconnects.

Mike holt has a interesting recent EC&M article
http://ecmweb.com/code-basics/article-230-services-part-1
Where he states
The rule is six disconnecting means for each service, not six service disconnecting means per building. If the building has two services, you can have a total of 12 service disconnects (six disconnects per service).
The thing that changed that no longer allows this is 230-2 Exception 3 (b)
 
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