The distinguishing difference between Manufactured Buildings and Mobile/Manufactured Homes is that the latter is transportable via the "built on" permanent chassis [550.2 Definitions, Mobile Home]. To my knowledge, Manufactured Buildings have no such chassis for transportability.
225.30 and prefab classrooms
- Thread starter dnem
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OK and OK. It has not been established the pedestal under discussion is of the metered type, as pedestals without meters also exist. But for the sake of discussion, let's proceed as you've set forth as I do not believe it'll make a difference.georgestolz said:
Actually they usually go up a conduit chase directly into the bottom of a panelboard mounted on an outside wall. Very seldom, if at all do they enter at one location and terminate at a location some horizontal distance away.
Yes, but in this regard, Article 550 requires an outside disconnecting means to be installed not on yet adjacent to the mobile home within 30 ft. (See "[Edited to add]..." below for additional comment.)
I'm not saying they don't. What I was saying is that when you have a mobile home in other than a mobile home park the code says it still must meet all the provisions as though it is in a mobile home park. Therefore, a mobile home is always considered to be "installed" on a mobile home lot, which is also considered a separate property which has a service run to it. Compare to an actual mobile home park, where the park is the property, but it is divided up into lots and each lot is considered to be a separate property. You said earlier one could run multiple feeders off a single service disconnect if it were on the outside of a single property with a single service. What makes this situation any different, once you accept it being a separate property as far as the NEC is concerned?
Let's not pretend. We got the book open on the matter now. Might as well explore all it has to offer!
Regarding taps, consider the schematic diagram below. Is there something in the book which rules out this interpretation?
View attachment 87
[Edited to add] Ohh... and regarding:
While I can't attest to all mobile homes, those that I have observed first hand have all had main ocpd's on the panelboard. For the sake of discussion, let's say this is true of all mobile homes and move on.
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I can see that there is some confusion about whether this building is covered by 545 or 550. I don?t know what the correct answer is.
George,
As far as my 2 statements,
?For trailers, 225 only applies to items not covered by 550.
550.32 & 33 covers services and feeders and nowhere restricts the number to one single supply.?
90.3 says, in part, ?Chapters 5, 6, and 7 apply to special occupancies, special equipment, or other special conditions. These latter chapters supplement or modify the general rules. Chapters 1 through 4 apply except as amended by chapters 5, 6, and 7 for particular conditions.?
So my first sentence is true. For trailers, 225 only applies to items not covered, modified, or amended by 550.
You?re right about the second sentence. While it?s true that 550.32 & 33 covers services and feeders and nowhere restricts the number to one single supply. It?s also true that 550.32 & 33 nowhere allows the number of feeders to be more than one single supply. So 550.32 & 33 is not modifying or amended 225 restrictions on the number of feeders. 225 would still apply.
I don?t see that 2 feeders would be code compliant whether 545 applied or 550 applied.
This one has a permanent chassis and it also has permanent diagonal beams that come together at a hitch.
David
George,
As far as my 2 statements,
?For trailers, 225 only applies to items not covered by 550.
550.32 & 33 covers services and feeders and nowhere restricts the number to one single supply.?
90.3 says, in part, ?Chapters 5, 6, and 7 apply to special occupancies, special equipment, or other special conditions. These latter chapters supplement or modify the general rules. Chapters 1 through 4 apply except as amended by chapters 5, 6, and 7 for particular conditions.?
So my first sentence is true. For trailers, 225 only applies to items not covered, modified, or amended by 550.
You?re right about the second sentence. While it?s true that 550.32 & 33 covers services and feeders and nowhere restricts the number to one single supply. It?s also true that 550.32 & 33 nowhere allows the number of feeders to be more than one single supply. So 550.32 & 33 is not modifying or amended 225 restrictions on the number of feeders. 225 would still apply.
I don?t see that 2 feeders would be code compliant whether 545 applied or 550 applied.
Smart $ said:
This one has a permanent chassis and it also has permanent diagonal beams that come together at a hitch.
David
Smart,
I have to disagree with your concept of taps.
The first disconnecting means is the main supplied by service entrance conductors, after that, every disconnecting means is a feeder supplied by feeder conductors. Conductors that leave the main disconnect to suuply a feeder disconnect are feeder conductors. Conductors that leave a feeder disconnect to supply another feeder disconnect are still categorized as feeder conductors. They are not feeder taps.
A tap is an additional conductor that is attached to a "trunk" conductor. The "trunk" conductor is protected at its allowable ampacity, the additional conductor, that is added as a tap, is not properly protected by its supply but rather protected by the OCD at its load end.
These trailers/buildings are not supplied by conductors that are tapped onto any other conductors. They are terminated on breakers on both ends. One end at the outside pedestal, the other end inside the trailer/building. The breakers at both ends are the correct amperage for the conductors being used to feed the trailer/building.
David
PS A question was raised about metering. There are no meters at the pedestal. Metering is done only at the service for the main permanent school building.
I have to disagree with your concept of taps.
The first disconnecting means is the main supplied by service entrance conductors, after that, every disconnecting means is a feeder supplied by feeder conductors. Conductors that leave the main disconnect to suuply a feeder disconnect are feeder conductors. Conductors that leave a feeder disconnect to supply another feeder disconnect are still categorized as feeder conductors. They are not feeder taps.
A tap is an additional conductor that is attached to a "trunk" conductor. The "trunk" conductor is protected at its allowable ampacity, the additional conductor, that is added as a tap, is not properly protected by its supply but rather protected by the OCD at its load end.
These trailers/buildings are not supplied by conductors that are tapped onto any other conductors. They are terminated on breakers on both ends. One end at the outside pedestal, the other end inside the trailer/building. The breakers at both ends are the correct amperage for the conductors being used to feed the trailer/building.
David
PS A question was raised about metering. There are no meters at the pedestal. Metering is done only at the service for the main permanent school building.
- Location
- Massachusetts
Smart $ said:
That is incorrect, Manufactured Buildings may or may not have a chassis for transportability.
Here is a picture of a typical job trailer
Here is a picture of the tags at the panel.
Both NH and MA tags call it a manufactured building.
It has a tag from the Moduler Building Institute
And it's listed by the Industrialized Building Commission.
This is not a structure covered by 550 and I doubt the class rooms are either.
Not that it makes much difference in this thread.
- Location
- Massachusetts
dnem said:
Smarts diagram does in fact show 'taps' per NEC definition.
I once supplied 3 separate manufactured Buildings
from one generator using a method smiler to smarts diagram using the tap rules.Yes, I can see the parameters by which you disagree... and I agree with you, now that you've provided missing and vital information to the discussion!!!dnem said:
I asked you way back (pause while I go find it) in post #13 about the internal arrangement of the pedestal. I also asked about the manner of connection at the other end of the pedestal source feeder conductors. I received no response... so I had to make the assumption that the 100A conductors were in fact tapped to pedestal load-side busses. Busses do qualify as a feeder conductors.
I'll concede to your point, but umm... is that a permanent chassis?iwire said:
Manufactured buildings, as you have pictured, can have a transportation chassis (aka trailer) but I'm sure in the state of Ohio you'd have a hard time convincing a court of law it is "an installed manufactured building" as long as that chassis is still under it!
Then we must also consider that "contractor's on-site offices" is specifically mentioned as an example of a "Mobile Home Not Intended as a Dwelling Unit" in 550.4(A).
- Location
- Massachusetts
Smart $ said:
I don't see why.
The definition of Manufactured building does not require or prohibit the chassis.
You find it makes more sense to call a structure designed from the ground up as a class room a mobile home?
Around in circles we go....
Read 550.4(A) it applies only to a structure that was designed to be a dwelling unit and is now seeing use as other than a dwelling unit.
If it was never a dwelling unit 550.4(A) dose not apply.
A mobile home has a HUD (Housing Urban Development) listing if you see a trailer with a HUD listing and it is now being used as a contractors trailer 550 still applies.
Bob
Come on now, Bob. Are you really that blinded? At best you could call it installed if you remove the axles, cut off the hitch a-frame, strap 'er down, and skirt it. But then again, I'm aware this practice is also observed, perhaps even required in some areas for mobile homes... and they are still considered "not permanently sited" mobile homes.iwire said:
Not saying it does.iwire said:
???iwire said:
That's your interpretation or one developed through supporting documentation that is not legally binding. 550.4(A) doesn't actually say that. It says, "A mobile home not intended as a dwelling unit...." Unless it is modified to read otherwise, it doesn't matter when or how the intent originated, only that it is so.iwire said:
Now that is a very valid point. However, in the state of Ohio a "trailer" meeting that description is a Manufactured Home and does not preclude other units not so listed as being mobile homes.iwire said:
I could quote additional passages of the ORC, such as the definition of an "industrialized unit", to support my assertions. In addition, remind you that the NEC is only law by adoption. State code supercedes it and only federal law overrides state code. And it all would be for what? I have better things to do with my time...ORC ? 3781.06 said:
- Location
- Massachusetts
Smart $ said:
I have no idea why you feel a manufactured building must be a permanently located.
One of the prime reasons for using manufactured buildings for classrooms is that they are easily removed when enrollment drops.
You can even lease manufactured buildings.
No reason at all a manufactured building must be permanently located.
Again you lost me.
It is not an interpretation it is what it says.
You concede that the section applies to a mobile home. (It has to as the scope of 550 only applies to mobile or manufactured homes)
It does not say any structure with wheels that is used as a contractor trailer will be treated as a mobile home.
It says mobile homes that are used as contractor trailers will be treated as mobile homes.
And it does not (I imagine) preclude manufactured buildings from being listed as manufactured buildings.
Thanks again for the obvious info, I had no idea the NEC must be adopted to mean anything.
Ah back to a typical smart $ move, now that I have shown you made an honest mistake you have better things to do with your time.
Kind of a pattern with you.
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It's not that I disagree with your assessment. It's more the fact that Ohio's laws do not recognize anything as what you are calling a manufactured building. The closest construction type is called an "industrialized unit"... leaving out all the bureaucracy crap involved, the result is once the unit is placed to state-approved plans, it ceases to be an industrialized unit and is thereafter under building code compliance (aka "permanently installed").iwire said:
- Location
- Windsor, CO NEC: 2017
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- Service Manager
I beat him to the punch - I found something better to do already.iwire said:
The conclusion that I'm drawing as of right now is that whether it has OC on the pedestal or is a tap, whether it falls under 545 or falls under 550, the question about multiple supplies isn't covered by either 545 or 550. Therefore it falls back to 230 or 225.
Since this installation was a feeder, this one falls under 225 which can only be approved under 225.30(E). I know a couple people have mentioned 225(B) but I can't see that you could say that you have either "multiple occupancy" or "sufficiently large" when we're talking about a double trailer connected together for a standalone school classroom.
David
Since this installation was a feeder, this one falls under 225 which can only be approved under 225.30(E). I know a couple people have mentioned 225(B) but I can't see that you could say that you have either "multiple occupancy" or "sufficiently large" when we're talking about a double trailer connected together for a standalone school classroom.
David
I agree 550 does not cover it explicitly. And implicit coverage is certainly vague at best. After reviewing 550, I was wondering how one should interpret 550.11(A), first sentence or two, as it relates to this and other multi-unit situations?dnem said:
While your at it, what about 550.19(B)?
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- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
Good call.
I think this Article is written poorly. The phrase "disconnecting means with branch-circuit protective equipment" is kind of an odd choice of words. Who cares if it's an MDP or a disconnect feeding an MLO?
That would seem to 'not encourage' seperate supplies for permanent feeders for semi-permanent MH's.
I think this Article is written poorly. The phrase "disconnecting means with branch-circuit protective equipment" is kind of an odd choice of words. Who cares if it's an MDP or a disconnect feeding an MLO?
georgestolz said:
George,
I'm not coming to the same conclusion. . You're focusing on "disconnecting means with branch-circuit protective equipment". . If you take a wider look, you might come to a different conclusion.
If you look at a larger section of the sentence you read, "disconnecting means with branch-circuit protective equipment in each unit". . I don't read this as the disconnect and OCD in the same enclosure, I read it as in the same unit.
I don't see a code violation with a disconnect feeding a MLO.
David
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