Service Disconnecting Means

[nakulak]

"100 Definitions: Building: a structure that stands alone or that is cut off from adjoining structures by fire walls with all openings therein protected by approved fire doors."

doesn't each apartment satisfy the definition of building ? (sorry for my ignorance on this, I haven't worked on apartments in 25 yrs or so. I realize that apts also fit the definintion of dwelling unit, but since they also meet the definition for bldg, doesn't that apply ?)

 

[jerm]

I don't doubt you for a second, all the evidence and wording seems to back you up, but this is frying my brain.

It also fried the brains of every journeyman I pointed it out to today. It references 230.2, which IMO contradicts it entirely. But then there was the rop to remove the exception in 08 and that was denied. This seems like a huge loophole. And the number of service disconnects is now only limited by the number of occupancies multiplied by 6? Weird stuff.

"100 Definitions: Building: a structure that stands alone or that is cut off from adjoining structures by fire walls with all openings therein protected by approved fire doors."

doesn't each apartment satisfy the definition of building ?

Not around here. Not at all. It depends on the size of the apartments in question, but usually when one catches on fire there are several that go along with it.

Jeremy
Tulsa, Ok

 

[M. D.]

I think it is a little clearer if you start at 230.71 first sentence

" The service disconnecting means for each service permitted by 230.2, or for each set of service entrance conductors permitted by 230.40, Exceptions 1,3,4,0r 5, shall consist of not more than six switches or sets of circuit breakers........."

So if you have five sets of service entrance conductors , one to each occupancy, you could have 30 disconnects but not more than six grouped in any one location.

I think some confusion comes from the fact that they dropped the

"or for each set of service entrance conductors "

from the second sentence of 230.71

" There shall be not more than six sets of disconnects per service "(or for each set of service entrance conductors) grouped in any one location. "

 

[George Stolz]

I can't pick apart the words, M. D. If I could see a gap, I'd be chipping at that sucker with a jackhammer in debate.

I agree that the words say what you and Don are saying: I'm saying the principle is cuckoo-bananas. If we can have 45 handles outside a building to kill all the power inside the building, and the NFPA considers that safe, why do we have a six-handle rule at all?

 

[M. D.]

I can't pick apart the words, M. D. If I could see a gap, I'd be chipping at that sucker with a jackhammer in debate. ........

Of that I have no doubt:smile:

This has been in the code for at least 60 years , I should think , if it were causing safety issues , it would be easy to demonstrate.

 

[don_resqcapt19]

why do we have a six-handle rule at all?

I have no idea. If it really was for safety the rule would not permit the service disconnects to be inside the building.
Don

 

[abe72487]

Service Disconneting Means

Service Disconneting Means

If there are Fire walls installed in the building then you could have six disconnects for each area that is separated by a fire wall.

 

[SmithBuilt]

If there are Fire walls installed in the building then you could have six disconnects for each area that is separated by a fire wall.

That's what I thought too. But if you read closely you will see the problem with that statement.






What is considered grouped? If you look at the handbook on page 137 exhibit 230.13. The enclosures with 6 disconnects in each, could be considered as 24 disconnects grouped.

This would be a hard sell with inspectors. I have an existing installation where I could use this though.

 

[George Stolz]

This has been in the code for at least 60 years , I should think , if it were causing safety issues , it would be easy to demonstrate.

If anybody knew to use it, or if any inspectors would sign it off. I doubt there are very many services out there making use of this exception, or else my green is showing.

Does anybody ever see this come to life? Is there an everyday example of it I'm just not thinking of?

why do we have a six-handle rule at all?

I have no idea. If it really was for safety the rule would not permit the service disconnects to be inside the building.

Interesting point.

 

[M. D.]

If anybody knew to use it, or if any inspectors would sign it off. I doubt there are very many services out there making use of this exception, or else my green is showing.

Does anybody ever see this come to life? Is there an everyday example of it I'm just not thinking of.

Well, the code panel thinks it is common,

Exception 1 to 230.40 is a necessary and commonly used allowance for
supplying power in multiple occupancy buildings. The building is still only
permitted to have one service riser or lateral that would allow the power to be
removed from all occupancies when necessary by the disconnection of the riser
or lateral conductors.

 

[jap]

I dont know if we got anywhere on this did we?
I was thinking of something else to stir the pot even more. if you think about it on a group metering system, where do you draw the line on the service entrance conductors? The conductors come from the utility xfmr and terminate on the buss bars of the Main Tap box of the Group metering system. If the main tap box does not have a Main disconnect, one could argue that the buss bars from the Main Tap box to the line side of each individual meter in the group metering system,(No matter how many) is still part of the service entrance conductors.If group metering had never been invented we would be back to putting several individual meters with tennant breakers underneith them to satisfy however many tennant spots there were to feed. If the power company was to swing (1) service overhead and daisy chain to all these service risers on the wall, each service riser would be its own service. I can see no difference in this example and a group metering setup that has more than (6) meters and disconnects to shut off.

 

[E.W. Hollenbeck]

Hello, this is my first time on the site. I have read all 30+ postings and think I can see how confusing this issue is. Let me ask a basic questing. On a duplex or a sixplex with only one service drop or laterial, do the two or six disconnects that are needed to shut off all power to the entire building need to be grouped in one location to comply Article 230.72? Each dwelling unit only has a one hour fire seperation between the units.