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#87732 - 04/09/04 06:15 AM Grouping of Service Disconnects  
George Little  Offline
Member
Joined: Jan 2004
Posts: 1,489
Michigan USA
Based on Article 230.40 Ex. 1, each occupant of a multi occupancy building is permitted to have a set of Service Conductors run for his/her occupancy. The Code goes on further to say that this set of Service Conductors is limited to six Service Disconnects located in one location 230.71(A) and 230.72(A). Now the question: If I have this situation and we have a central location for the utility supply, can each of these occupants have their Service Disconnects (up to six) located near the Service Point and exceed the magic number of six? In other words, occupant #1 has four Service Disconnects on his Service Conductors and occupant #2 has four Service Disconnects on his Service Conductors. Both of these occupant's Service Disconnects are properly identified as to load served etc.and are located in the same general area. Is this a problem from a Code stand point or a safety hazard?


George Little

2017 / 2014 NEC & Related Books and Study Guides

#87733 - 04/09/04 08:20 AM Re: Grouping of Service Disconnects  
Yoopersup  Offline
Member
Joined: Mar 2003
Posts: 822
Michigan
George
Look on pages 129-130-131 N.F.P.A. N.E.C.
Code Handbook 2002.Exhibit 230.13. Not Code section. Exhibit(Illustration)Page 131

Note Handbook not Code book.


#87734 - 04/10/04 07:48 PM Re: Grouping of Service Disconnects  
russ m  Offline
Member
Joined: Feb 2003
Posts: 169
Burbank,IL,USA
230.40 Ex1 deals with services of differnt voltages or phases.

I have no idea what pages 129, 130, or 131 have to do with this. Is that from the 2002 NEC?

Service entrance conductors are the conductors that are fed from the POCO overhead or underground feed. (See the definition in article 100) There are only Six disconnects maximum (six hand movements) allowed to turn off the power.


#87735 - 04/10/04 09:02 PM Re: Grouping of Service Disconnects  
DougW  Offline
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Joined: Jun 2003
Posts: 1,143
North Chicago, IL
Quote
In other words, occupant #1 has four Service Disconnects on his Service Conductors ...


Service Disconnect isn't defined in Art. 100 by that title, but as I understand it, it is AKA a "main"... the "numero uno" breaker (residential min 100A), that, by being turned off, kills power to all of the branch circuits contained in the same panel (main breaker style), or any panels "downstream" from it's location if remote...say at the meter.

Four Service Disconnects for one residence? Am I missing something?


#87736 - 04/12/04 07:58 AM Re: Grouping of Service Disconnects  
Yoopersup  Offline
Member
Joined: Mar 2003
Posts: 822
Michigan
Russ M
Code are pages from the N.F.P.A. Electrical Code HANDBOOK Not Code book 2002. The pages deal with service entrance conductors underground and overhead in Pictures!!!!It Does apply and deals with the six disconnect rules. Maybe you should expand your Libary a bit. The book is put out by the NFPA same ones who do the code.


#87737 - 04/12/04 10:23 AM Re: Grouping of Service Disconnects  
iwire  Offline
Moderator
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
Quote
Four Service Disconnects for one residence? Am I missing something?


Doug if I remember you are a Chicago resident?

If so you may have some different rules for this.

But the NEC allows up to 6 (7 if there is a fire pump) disconnects for the "service disconnect" to a structure.

There are a lot of ways this could happen, one way would be a 320/400 meter socket feeding four 100 amp main breaker panels side by side.

Each one of the 4 breakers is a service disconnect.

In commercial applications service conductors may enter a piece of service rated switch gear with no single main.

In that switch gear you might install six 800 amp breakers giving you 4800 amps of service with out the need of a very expensive 480 volt 4800 amp GFP main breaker unit.

Bob


Bob Badger
Construction & Maintenance Electrician
Massachusetts

#87738 - 04/12/04 11:46 AM Re: Grouping of Service Disconnects  
Yoopersup  Offline
Member
Joined: Mar 2003
Posts: 822
Michigan
Chicago code 6 six disconnect rule is, 18-27-230-71
Number of Services 18-27-230.2
Number service entrance conductors 18-27-230.40
2002 Chicago Electrical Code


#87739 - 04/12/04 11:49 AM Re: Grouping of Service Disconnects  
iwire  Offline
Moderator
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
Thanks Yoopersup.

Bob


Bob Badger
Construction & Maintenance Electrician
Massachusetts

#87740 - 04/12/04 08:37 PM Re: Grouping of Service Disconnects  
russ m  Offline
Member
Joined: Feb 2003
Posts: 169
Burbank,IL,USA
yoopersup:

All you had to say, was that it was from the 2002 NEC Handbook.


#87741 - 04/13/04 01:03 AM Re: Grouping of Service Disconnects  
DougW  Offline
Member
Joined: Jun 2003
Posts: 1,143
North Chicago, IL
I understand the "rule of six" per structure (230 (F) in the 96 NEC). It just seemed like the question had multiple service disconnects for one residence in a multi-occupancy structure.

The question seemed to be awkwardly worded - Even though term service disconnect was being used, it seemed to me that George could be inadvertantly referring to branch circuits for each occupancy within a multi occupancy structure, rather than "main d/c's" that would control power to a sub-panel located inside each occupancy.

That's why I was surprised/confused.

BTW - I second the recommendation for the NFPA Code Handbook. EXCELLENT reference / explanatory material.


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