6 disconnect rule violation?

[marc deschenes]

Re: 6 disconnect rule violation?

I don't think comparing a switch to the buss inside a panel is appropriate . They are in no way the same it is not the job of a buss to interrupt the flow of current . The rating of the breaker to the rating of the switch is a more accurate caparison.

I would still love to know if the MLO panel in the original post says
anything like this:
?Suitable for use as service equipment when not more than six main
disconnecting means are provided and when not used as a lighting and appliance branch-circuit
panelboard ; see Section 408.14 (384?14) of the NEC.?

I bet it does , and if it does , it is a violation of 225.36 (2005)

408.14 in 2005 is 408.36

 

[hurk27]

Re: 6 disconnect rule violation?

By Marc: The rating of the breaker to the rating of the switch is a more accurate caparison.

How? A breaker is required to be sized to protect the conductors feeding a load and can be smaller than what it protects and still be safe.
A switch or disconnect on the other hand is rated for the load it will carry, and can't be smaller, but can be larger, and still be safe.

They are total opposite of one another?

Ok now for Mike:

The requirement for not more than two mains (disconnects) in a panel board can be found in 408.36 but I have already pointed this out.
It even goes so far as to say just how many single pole breakers (disconnects) that can be installed in it.

It does? Where does it say this in 408.36?
Remember a single disconnect can have multiple poles. And multiple single pole breakers with a handle tie is considered one disconnect. and a main breaker for a 120/240 volt service is a two-pole multiwire disconnect.

If you are installing a panel board in this remote building there is no escaping the requirements found in 408. The listing on a main lug panel will state that when it is used as service equipment it must conform with 408.

"when it is used as service equipment"
Yes it says that but in this garage it is not being "used as service equipment". If it was it would be fed by unprotected service entrance cables, the grounded conductor (neutral) will be bonded to the grounding conductor. (Main bonding screw installed).

This would not be allowed with a 4-wire feeder fed panel at a remote garage unless 230.40 exception #3 was used, or 250.32(B)(2) was used. the latter would still not cause it to be service equipment.

But in any case it will not be service equipment.

Here is why.
Look at the definition of service equipment in article 100:

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.

They do not connect to the load end of service conductors, so it is not used as service equipment.
When we install a sub panel and we happen to use a main breaker panel and it even says "suitable for use as service equipment" is it a service panel? No. it's "suitable for use as service equipment" But that does not say it is service equipment, it only saying it can be used as service equipment if is connected to service conductors. If it is not connected to service conductors it is not service equipment. and the service equipment stops at the main service disconnect 230.1, so even a main panel in a dwelling is not service equipment if there is a disconnect ahead of it. That is fact.

Have you read 250.32 lately? I think you will find that a grounding electrode is required at the separate building just like at the service

The bonding of the grounded conductor (Neutral) to the grounding in the building has nothing to do with an electrode requirement.
It has to do with the bonding of the neutral conductor (grounded circuit conductor) to the grounding in the building, weather it be the EGC's or GEC or both. This is required at any service equipment that is used as service equipment, not at a sub panel!

I am opened minded to any explanation of what you think this means. Give it a shot and explain what suitable for service equipment means. Please insert code references.

I did see above. as I have been putting in allot of overtime, since my vacation and shortage of good help put me behind.

I enjoy these little discussions as it keeps me looking.
And I did learn one thing I didn't know (most likely because I never read it this closely) is I never noticed that the handle ties was only allowed for multiwire circuits in 225.33(B) and in 230.71(B).
And that 225.33 spells out that it can not be more than six switches or six circuit breakers mounted in a single enclosure? I only saw the Six disconnects. which would explain 225.33(B) on the multiwire circuits?

 

[George Stolz]

Re: 6 disconnect rule violation?

Originally posted by hurk27:

By Marc: The rating of the breaker to the rating of the switch is a more accurate caparison.

How? A breaker is required to be sized to protect the conductors feeding a load and can be smaller than what it protects and still be safe.
A switch or disconnect on the other hand is rated for the load it will carry, and can't be smaller, but can be larger, and still be safe.

They are total opposite of one another?

I think he's saying that to compare apples to apples, you'd need to compare the circuit breaker's handle with the rating of a simple switch.

As opposed to comparing a switch to an empty panel and comparing "ratings". I understand your idea (clever thought process) but it's not quite what Marc was thinking of, I believe.

I enjoy these little discussions as it keeps me looking.
And I did learn one thing I didn't know (most likely because I never read it this closely)...

I've learned a lot! That's the great thing about these discussions, it really gets to the nuts and bolts of things, when you tear them apart!

I don't mind looking a little stupid for the first several pages if I come away a little brighter in the end.

Edit to correct my quotes

[ November 30, 2005, 12:36 AM: Message edited by: georgestolz ]

 

[George Stolz]

Re: 6 disconnect rule violation?

Originally posted by mvannevel:
Is this sloppy code writing, or did the CMP not see any need to total the handles for this type of installation? I tend to believe that they saw no need for it.

I think the lack of a 225.80 confirms that theory.

Unfortunately, they didn't leave a clue as to how to determine what the rating is (singular) of a bunch of enclosures with various handles sprinkled in them. One thing is fairly clear: They either didn't intend for 230.80's method to be used at all, hence it obvious omission, or, they thought it was obvious that it was the method to use.

 

[hurk27]

Re: 6 disconnect rule violation?

True I can't know what he was thinking on this but even though, the rating of these two are for totally opposite requirements, And actually as far as ratings go, a switch will be more comparable to the rating of a load center since the two requirements are for the same purpose (How much current they can safely carry). It is the same rating requirement that is for wire. The rating of a breaker is the opposite as it is not for how must load it can safely carry as it sets the limit that can be imposed upon the conductors, (weather it be a busbar or contacts in a switch) It is a protector that has a maximum that it can be, but rating of a conductor or switch is a minimum that can not be less than to maintain safety. So a switch will treated more like a conductor in the requirements of its rating. And that conductor is the busbars in a panel.

 

[hurk27]

Re: 6 disconnect rule violation?

The simple answer to all this is common sense.
If we were to install a disconnect ahead of this panel then the NEC would not have needed the six disconnect rule and it's words would have been for naught! The panel then could be filled with as many breakers it is so listed for. I do believe that the CMP's who have done their best to keep it a small book believe that we electricians are somewhat qualified to use the info in it. The problem is we can get hung up on some of the most simple requirements that we tend to think back-wards when trying to reverse engineer the requirement. so instead of thinking about why the six disconnect rule first think how can we by code fill the panel as listed? (have one disconnect ahead of it) Then think how we are allowed up to six? with out a disconnect ahead of it.
See so simple

 

[david]

Re: 6 disconnect rule violation?

I look at a 240/120 volt service on a utility pole last week for the municipal sewer authority. It was a 100 amp two circuit panel suitable for service equipment. The 100 amp service cable fed the main lugs. There was one 15 amp single pole breaker. I scratched my head not more then six throws of the hand. The fact that there was only one single pole breaker had me wondering where is the service disconnect. I also thought it would be silly to ask for a second breaker that was not going to be connected to anything. Third if I ask for the second breaker the service would have to be increased to 30 amps. The branch circuit needed to be protected at 15 amps. I thought a better approach would have been a 120 volt service.

 

[david]

Re: 6 disconnect rule violation?

It would seem you do not have to have any breakers installed at the time of inspection if your service entrance (OR FEEDER to stay on topic) is fed to the lugs of a main lug panel. All I have to insure is the service is sized for the load being served and there are know more they six throws of the hand installed.
No throws of the hand is less then six. So zero to six is ok then right?

 

[don_resqcapt19]

Re: 6 disconnect rule violation?

David,
225.31 requires "a means of disconnect". You must install at least one. 225.33 permits you to install up to six, but that does not change the requirement to provide at least one.
Don

 

[marc deschenes]

Re: 6 disconnect rule violation?

quote:
By Marc: The rating of the breaker to the rating of the switch is a more accurate caparison.

By Hurk27; How? A breaker is required to be sized to protect the conductors feeding a load and can be smaller than what it protects and still be safe.
A switch or disconnect on the other hand is rated for the load it will carry, and can't be smaller, but can be larger, and still be safe.

They are total opposite of one another?

A circuit breaker can be used as a disconnect switch. I have never before heard that the panel rating , regardless of the size breaker , is what the disconnect rating is.
The circuit breaker is the disconnect switch and in some cases it is also the OCPD.

I think one could argue that the rating of the panel is determined by the feeder protection and not bt the listing / lable.
putting a 100 amp panelboard one a 60 amp feeder does not make for a 100 amp rated disconnect at the garage. Though you could use a 100 amp breaker for a main because it is just a disconnect not OCPD, that is acomplished at the panel where the feeder originates.

 

[George Stolz]

Re: 6 disconnect rule violation?

Originally posted by don_resqcapt19:
225.31 requires "a means of disconnect". You must install at least one.

While I feel a little absurd arguing this point (as it has no application), I will say this:

If none of the conductors are connected to the supply, then there are no conductors supplying the structure. Therefore they would not require a disconnecting means. It is the interest of energizing conductors that mandates they be disconnected, IMO.

 

[George Stolz]

Re: 6 disconnect rule violation?

Originally posted by marc deschenes:
putting a 100 amp panelboard one a 60 amp feeder does not make for a 100 amp rated disconnect at the garage.

That's the goofy thing about how this is written. The feeder supplying the structure is required to be sized according to the load. But the requirements for the disconnecting means are totally unrelated.

A key element missing from 225 as compared to 230, is that (NEC-2002) 230.42(B) requires the conductors supplying the service disconnect to match the rating of the service disconnecting means. There is no such requirement (as far as I can see) in 225.

I was thinking about my pole barn yesterday morning, as it relates to this discussion. I have a calculated load of 5 amps, absolutely max. I installed a small panel in the barn and installed two breakers in it (One for lights, the other for receptacles). So my panel has to be rated for 30 amps, but the wire feeding it can be 14 AWG.

If I were to install another breaker for some odd reason, I'd need a panel rated for 60 amps, although I could still feed this panel with 14 AWG conductors.

 

[mvannevel]

Re: 6 disconnect rule violation?

George, I really think they didn't leave a clue as to how to determine that rating because all that's needed is to look at the rating of the single disconnect or the enclosure to be used for the six disconnects. We keep wanting to go back to 230, but this is a horse of a completely different color. We have feeder conductors that have overcurrent protection not unfused service conductors. That's why the requirements are different for the two articles. All article 225 is asking us to do is to disconnect all ungrounded conductors that supply or pass through the separate building. We can do it with a single throw or we can do it with 6 swipes of the hand, but that's all we're looking to do. We're not protecting conductors or panelboards (that's already been taken care of with our feeder OCPD) we need only disconnect the conductors. My opinion is that in this instance that rating is there solely for the capacity for the number of circuits served (and hence, the reasoning for the absence of a 225.80). And, in my opinion, the ability to use the panelboard rating to meet 225.39.

Something else we need to think about is the absence of any requirement for overcurrent protection for the feeder or panelboard at this separate building. There is no 225.90 or 225.91 requiring overcurrent protection for each ungrounded feeder conductor at the separate building or that it be an integral part of the disconnecting means required for the building. Again, I don't think this was an omission, but rather a recognition of the difference between a service and an outdoor feeder.

quote:
--------------------------------------------------------------------------------
We could just as easily (and correctly) install an unfused pull-out, safety switch, or molded case switch.
--------------------------------------------------------------------------------

Correctly? No. Not for every circumstance.

If I have a 60 amp feeder running out to a panel, I'm more likely to use the panel in some method to get 15 and 20 amp circuits out of it. More work to put a switch in ahead of a panel, that could house the switch(es) in itself.

What I wanted to point out here was the fact that if, for some reason, we did want a single disconnecting means for this building, it needn't be fused at all. I see your point that it wouldn't necessarily be easy to install a disconnect separate from the panel, but it would be just as correct. And it doesn't need to provide overcurrent protection.

As I said earlier, we really just need to look at what we're trying to do here. What the Code is asking us to do. And that's disconnect the conductors. Nothing more, nothing less. If this were a service (think exception #3 to 230.40) or an outside tap we'd have a different set of requirements. But in our situation we're merely supplying a means of disconnect.

 

[marc deschenes]

Re: 6 disconnect rule violation?

If the disconnect for the structure is required to be rated at 60 amps and one or more circuit breakers (not more than 6) are used , they serve as "one" , does it not stand to reason that the combined rating of the breakers must be 60 amps.
I do not believe there is any language in the N.E.C. that supports the idea that the rating of the buss in a panel serves as a rating for the disconnect.
The disconnect is the breaker not the panel .

 

[mvannevel]

Re: 6 disconnect rule violation?

Originally posted by marc deschenes:
If the disconnect for the structure is required to be rated at 60 amps and one or more circuit breakers (not more than 6) are used , they serve as "one" , does it not stand to reason that the combined rating of the breakers must be 60 amps.

If it were a service, yes, because it's spelled out that way. I really believe that if that's what they intended, then they would have stated it as they did in 230.80. There is no need for protection here, only capacity.

The disconnect is the breaker not the panel .

The disconnect is the breaker and the panel. If we used a fused disconnect, we could have a 60 ampere rated disconnect and only install 50 ampere fuses. Our disconnect is rated 60 amperes regardless of what the rating of the fuses are. Just as the panel would be rated 60 or 100 amperes regardless of the rating of the breaker or breakers installed.

I do not believe there is any language in the N.E.C. that supports the idea that the rating of the buss in a panel serves as a rating for the disconnect.

The thing is, there's no language in 225 that supports the idea of adding the ratings of the switches as the rating of the disconnect in this instance either. So I guess, absent of any official interpretation from CMP #4, we can't know for sure what they intended. Since they cover both 225 and 230 they should have a reason for having written them differently.

 

[marc deschenes]

Re: 6 disconnect rule violation?

mvannevel , you said "George, I really think they didn't leave a clue as to how to determine that rating because all that's needed is to look at the rating of the single disconnect or the enclosure to be used for the six disconnects."


You seem to be saying that if I use a 100 amp MLO pane on a 60 amp feeder and I install a 15 amp circuit breaker , I now have a 100 amp rated disconnect ?? Even though it is the 15 amp breaker that serves as the disconnecting means at the separate structure ???

Am I understanding you correctly?

 

[jwelectric]

Re: 6 disconnect rule violation?

I couldn?t sleep at all last night thinking about someone installing a feeder to a remote building with out installing a switch gear for a disconnect when the answer jumped into my head like sugar plumbs on Christmas eve night.

Think of a mobile home. I install a 150 amp service on the pole and install 2/0 aluminum conductors that land under a 200 amp breaker in the inside panel.

What is the inside panel rated at? Does it comply with 225? Does it comply with 408?

Now at least 10,812 posts are coming that will say this isn?t the same thing but it does make for a good comparison.

I fail to see where the problem is concerning this remote panel. Maybe I am missing something. A disconnect is required whether it is a fused or non fused, knife or pull, breaker or breakers or a cord and plug it is still required.

I will always install a main breaker panel and never be faced with such debate about this with the code enforcement official.

 

[mvannevel]

Re: 6 disconnect rule violation?

Marc, in essence, yes. Like I said earlier, if I have a 60 ampere fusible disconnect and the fuses I install are 50 amperes, have I changed the rating of the disconnect? No, it's still rated at 60 amperes. Same with the MLO panel, if it's rated at 60 or even 100 amperes, that's the rating regardless of what I fuse it at. The disconnect is the combination of the enclosure and the overcurrent device(s) installed in it.

Let's look at this from a different angle. What is the reasoning behind 230.80? Why are we required to combine the ratings of the switches or breakers?

 

[George Stolz]

Re: 6 disconnect rule violation?

Originally posted by jwelectric:
I couldn?t sleep at all last night thinking about someone installing a feeder to a remote building with out installing a switch gear for a disconnect...

Nyquil does the trick for me. Or two beers.

Think of a mobile home. I install a 150 amp service on the pole and install 2/0 aluminum conductors that land under a 200 amp breaker in the inside panel.

What is the inside panel rated at?

Presumably 200 or 225 amps.

Does it comply with 225?

If it's outside or inside nearest the entrance to the building, sure. (Around here, it would essentially have to be outside.)

Does it comply with 408?

Yes, it has overcurrent protection not exceeding the panel rating at the pole and at the panel. That's the limit of two.

Now at least 10,812 posts are coming that will say this isn?t the same thing but it does make for a good comparison.
How?

I fail to see where the problem is concerning this remote panel. Maybe I am missing something.

What did you expect us to pick on?

edit to fix quotes again

[ November 30, 2005, 08:26 PM: Message edited by: georgestolz ]

 

[david]

Re: 6 disconnect rule violation?

230.70 General.
Means shall be provided to disconnect all conductors in a building or other structure from the service-entrance conductors.

225.31 Disconnecting Means.
Means shall be provided for disconnecting all ungrounded conductors that supply or pass through the building or structure.
__________________________________________________
David,
225.31 requires "a means of disconnect". You must install at least one. 225.33 permits you to install up to six, but that does not change the requirement to provide at least one.
Don
__________________________________________________

Absolutely, My Point exactly and I am glad some one Bit!

In my first post I can scratch my head pass a service walk away because there is no such requirement in 230.70 We are disconnecting the conductors in a building from the service entrance conductors this can be done using main lugs

However in 225.31 we are required to disconnect all un- grounded conductors supplying or passing through. How do you use a main lug to disconnect the supply conductors? You can not. The differences between 230.7 and 225.31 may be subtle but when you compare what you are disconnecting I do not see how a main lug could be used to disconnect the supply conductors when they are a feeder.