Without a load calculation of what all may be associated with the trailer, that may be simply a complete waste of time and effort.
JAP>
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High school trailer
- Thread starter hhsting
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Without a load calculation of what all may be associated with the trailer, that may be simply a complete waste of time and effort.
JAP>
hhsting
Senior Member
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- Glen bunie, md, us
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- Junior plan reviewer
The question is about which NEC 2017 article 545 or 550 apply not about how to install
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Terminator5047
Senior Member
- Location
- Saint Louis
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- Electrician
I fail to understand the big dilemma...
as Fredb states, you, your AHJ or whomever makes the call in your jurisdiction can rule 550 vs 545 and enforce accordingly.
as Fredb states, you, your AHJ or whomever makes the call in your jurisdiction can rule 550 vs 545 and enforce accordingly.
It would not be a problem no matter what Article is enforced
Local call. If the decision is made Art 550, yes. If other, no.
- Location
- Illinois
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- retired electrician
The code did a terrible job with this type of installation in the 2017 code and earlier. This was fixed in the 2020 code and these installations are covered by 545 in the 2020 code.
I have never seen a portable class room or construction trailer actually installed in accordance with the rules in 550. We always take the power supply directly to the panel in the portable building.
Since you are doing plan review, I assume you are the AHJ, and if so, I would just use the requirement as found in 545 in the 2020 code for this application.
I have never seen a portable class room or construction trailer actually installed in accordance with the rules in 550. We always take the power supply directly to the panel in the portable building.
Since you are doing plan review, I assume you are the AHJ, and if so, I would just use the requirement as found in 545 in the 2020 code for this application.
kwired
Electron manager
- Location
- NE Nebraska
Maybe. I think 545 part II is primarily for any building intended to be somewhat easily relocated. I say that because a lot of things can be relocated but not necessarily designed to be easily relocated. The fact it is intended to be there temporarily does help support calling it a 545 application as well. appears to need to be supplied by a feeder and not a service to utilize 545, but unlike a mobile home disconnecting means seems to be able to be in or on the building.
kwired
Electron manager
- Location
- NE Nebraska
Art 550 definitions - see manufactured home - informational note 2 that refers you to HUD standards. If it doesn't comply with HUD it is not a manufactured home.
Then see last paragraph in mobile home definition (550 again), and it says for this code the term mobile home includes manufactured homes unless otherwise specified.
Then see last paragraph in mobile home definition (550 again), and it says for this code the term mobile home includes manufactured homes unless otherwise specified.
hhsting
Senior Member
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- Glen bunie, md, us
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- Junior plan reviewer
So what would mobile homes include besides manufacturer homes? Does it include anything that has wheel or something else? Seems like mobile homes include manufactured home plus something else
Also:
Mobile home built per HUD is manufactured home. 550 applies
Mobile home not built per HUD go to NEC 2017 section 545
Then what does term mobile homes for NEC 2017 section 550 definition and 550.4?
Fred B
Senior Member
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- Upstate, NY
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- Electrician
What is Article 550.4 referring to then if it's not what the narrative actually says in title and the following narrative 550.4(A) Mobile Home Not Intended as a Dwelling Unit. ?
Electrically this section [550.4(A)], after some preliminary definition and caveats continues with: "It shall, however, meet all other applicable requirements of this article if provided with an electrical installation intended to be energized from a 120-volt or 120/240-volt ac power supply system." (NEC 2017)
I've seen many structures that from the outside other than being very "plane jane" is indistinguishable from a dwelling unit type of mobile home. I have seen these "plane Jane's" used as contractor offices, banks, school classrooms and even a diner.
Article 545 from my perspective is clearly indicated in structures that are part of or modules within a larger structure that is factory or manufactured as a component of the overall building. I've seen these, they are complete modules that are moved to a site then connected with other matching or linking modules, electrical and other mechanicals are fully installed in each module then interconnected on site.
Other forms may be less clear in application covered by 545, but may still be a 545 structure. IDK
If the classroom being described here is module as I suggest above, it would appear to be a 545 structure. But if it is fully free standing, whether a single section or part of a "double wide" I see it more related to 550 as 550.4 would make it applicable. No matter if wheels remain or not.
The difference also may be seen if the manufactured structure has only branch circuits brought into it and no panel it would likely be a 545, if it has feeder or service conductors with it's own panel then likely a 550 structure.
None of these statements are absolutes but more generalities. If as @don_resqcapt19 indicates the 2020 makes a better clearification, I would be interested in the wording that makes it clearer as I don't have 2020 (were under the 2017 here).
As a side question, if a newer code adds clarity to an ambiguous code of an older cycle that a jurisdiction might be under, can we use the newer code to justify or clarify the ambiguity of understanding?
I realize not useful where there is an actual change in the code such as adding AFCI requirements like happened between 2008 to 2014, or the exterior emergency disconnect of 2020.
Electrically this section [550.4(A)], after some preliminary definition and caveats continues with: "It shall, however, meet all other applicable requirements of this article if provided with an electrical installation intended to be energized from a 120-volt or 120/240-volt ac power supply system." (NEC 2017)
I've seen many structures that from the outside other than being very "plane jane" is indistinguishable from a dwelling unit type of mobile home. I have seen these "plane Jane's" used as contractor offices, banks, school classrooms and even a diner.
Article 545 from my perspective is clearly indicated in structures that are part of or modules within a larger structure that is factory or manufactured as a component of the overall building. I've seen these, they are complete modules that are moved to a site then connected with other matching or linking modules, electrical and other mechanicals are fully installed in each module then interconnected on site.
Other forms may be less clear in application covered by 545, but may still be a 545 structure. IDK
If the classroom being described here is module as I suggest above, it would appear to be a 545 structure. But if it is fully free standing, whether a single section or part of a "double wide" I see it more related to 550 as 550.4 would make it applicable. No matter if wheels remain or not.
The difference also may be seen if the manufactured structure has only branch circuits brought into it and no panel it would likely be a 545, if it has feeder or service conductors with it's own panel then likely a 550 structure.
None of these statements are absolutes but more generalities. If as @don_resqcapt19 indicates the 2020 makes a better clearification, I would be interested in the wording that makes it clearer as I don't have 2020 (were under the 2017 here).
As a side question, if a newer code adds clarity to an ambiguous code of an older cycle that a jurisdiction might be under, can we use the newer code to justify or clarify the ambiguity of understanding?
I realize not useful where there is an actual change in the code such as adding AFCI requirements like happened between 2008 to 2014, or the exterior emergency disconnect of 2020.
hhsting
Senior Member
- Location
- Glen bunie, md, us
- Occupation
- Junior plan reviewer
I am wondering too they should put in code at the beginning things that make language more clearer in the next cycle but Not changes can be used to mean same thing can be used previous cycle
What I found useful for this job is the following link
Manufactured homes are Federal HUD standard and can be moved once set as stated in link ( which is 550 per blue commentary 545.1 nec 2017 version)
Manufactured building are state or local as stated in link (which is 545 per blue commentary 545.1 nec 2017 version). Whats strange is the link states modular building once move, assembled on site and set permanent foundation cannot be moved???
For further explanation see blue commentary 545.1 nec 2017 version.
However all the above still does not explain why have definition of mobile home nec 2017 550? Does this mean mobile home can mean other items besides manufactured home? If so then what are they?
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kwired
Electron manager
- Location
- NE Nebraska
Another key phrase that is in art 550 definitions of manufactured and mobile home is "built on a permanent chassis".
Your OP portable classroom may or may not have this, but likely does as it keeps you from needing to add stabilizing beams and such every time you move it. Wheels may come off, even axles may come off when set but the chassis typically remains under the structure on mobile and manufactured homes covered in 550.
Your OP portable classroom may or may not have this, but likely does as it keeps you from needing to add stabilizing beams and such every time you move it. Wheels may come off, even axles may come off when set but the chassis typically remains under the structure on mobile and manufactured homes covered in 550.
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