Mobile Home

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jimwalker

Senior Member
Location
TAMPA FLORIDA
Re: Mobile Home

"Aha, but there is nothing stopping us from using the same GE or GES for multiple structures, even if a lengthy GEC is needed. "

Ok i agree we can share the ground rods.
So if the first rod or rods are at the pole and we go from that service to the mobile panel with 4 wires are we not indeed connecting the rods to the mobile panel by way of the grounding conductor ? Or is there a problem because they are not continuious from the rod ?
 
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petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Re: Mobile Home

Originally posted by augie47:
perhaps I should re-word that....
for the record: doesn't make a dime one way or the other to me...I am an inspector...one who tries very hard to enforce the CODE, not what I wish, not what I'd like to see personally, but the CODE...but, I read the ROPs etc and try to take intent in to the picture...perhaps thats wrong, but I sure don't think the intent of 250-32 is to require a second grouding electrode 2'on a MH with a GE and GEC at the serice pole 2' away.
My comment was more to the effect that I wonder how many inspectors interpret the code this way.
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Does the code actually say that you have to have a seperate GE at a seperate structure? Or only that it has to have a GE?

There does not appear to be a rule regulating how far from the structure the ground rod can be, so why not put one rod in between the two and run GEC to the same rod from both structures?

Not advocating this mind you, except in a devil's advocate kind of way.
 
don_resqcapt19

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Re: Mobile Home

250.50 Grounding Electrode System.
If available on the premises at each building or structure served, each item in 250.52(A)(1) through (A)(6) shall be bonded together to form the grounding electrode system. Where none of these electrodes are available, one or more of the electrodes specified in 250.52(A)(4) through (A)(7) shall be installed and used.
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iwire

iwire

Moderator
Staff member
Location
Massachusetts
Re: Mobile Home

Don I saw that before you posted but what is the maximum distance an electrode can be from a structure before it is not 'at that structure'. :confused:

In this thread we where talking about two structures just a few feet apart.
 
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jimwalker

Senior Member
Location
TAMPA FLORIDA
Re: Mobile Home

actually ran into something almost this crazy.Builder had a model that came 2 ways.House 10 feet from garage,one had breezway one didn't.But changes everything.Yes a 2x4 makes it attached but we both know it changed nothing electrically :D
 
roger

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
Re: Mobile Home

Jim,
Originally posted by jimwalker:
Nail a 2x4 between the pole and trailer and problem would be solved :D
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you should patent this idea. :D

Roger
 
don_resqcapt19

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Re: Mobile Home

Bob,
I think that the works "at each" will require a grounding electrode system at each and every structure, and not a common one or multiple structures. I don't see any electrical reason, only a code reason.
Don
 
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taylorp

Guest
Re: Mobile Home

Ladies and Gentlemen:

GG and haskindm are correct in their description of Mobile Home installations. A second grounding electrode is not required. Mobile Homes are covered in article 550 of the NEC, which is Chapter 5. Chapter 5 modifies or supplements Chapters 1-4.

If you will carefully read 550.32, the mobile home service shall not be mounted in or on the mobile home. Mobile home services are not separate structures as far as the code is concerned. A mobile home service mounted on a pole or pedestal up to 30 feet away is still part of the mobile home.

The panel board located inside the mobile home should be fed with 4 insulated conductors (2 hots, 1 neutral, and 1 EGC) from the mobile home service. Of course, the "neutral" is isolated once inside the mobile home.

550.32 states that grounding
at the disconnecting means shall be in accordance with 250.32
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Well if you will look at 550.2 Definitions, Mobile Home Service Equipment, you will see that the mobile home service IS the disconnecting means and requires a Grounding Electrode and GEC.

The panel board located inside the mobile home is simply connected as a sub panel per 250.24(A)(5), 250.142(B), 408.40 and 550.11(A).

We have hooked up many, many Mobile Homes here in the South, and not one AHJ has ever required an additional Grounding Electrode for the subpanel located inside the Mobile Home. Does anyone install an additional grounding electrode and GEC for subpanels they wire within residences?

Again, GG and haskindm are correct in their posts.

[ August 14, 2005, 03:32 AM: Message edited by: taylorp ]
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
Re: Mobile Home

Originally posted by taylorp:
Mobile Homes are covered in article 550 of the NEC, which is Chapter 5. Chapter 5 modifies or supplements Chapters 1-4.
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Yes 550 does modify some of the other sections.

However there is nothing in 550 that modifies the definition of structure.


Originally posted by taylorp:
If you will carefully read 550.32, the mobile home service shall not be mounted in or on the mobile home.
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Agreed, and we all knew that. :)

Originally posted by taylorp:
Mobile home services are not separate structures as far as the code is concerned.
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Please show us the section in 550 that modifies the definition of structure.

Originally posted by taylorp:
A mobile home service mounted on a pole or pedestal up to 30 feet away is still part of the mobile home.
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No, the service 30' away is not 'part of the mobile home'.

Originally posted by taylorp:
We have hooked up many, many Mobile Homes here in the South, and not one AHJ has ever required an additional Grounding Electrode for the subpanel located inside the Mobile Home.
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That has no bearing on what the NEC requires. :D

Originally posted by taylorp:
Does anyone install an additional grounding electrode and GEC for subpanels they wire within residences?
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Yes, every time the sub panel is located in a separate structure like a detached garage.

Originally posted by taylorp:
Again, GG and haskindm are correct in their posts.
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Well again in my opinion GG, haskindm and now taylorp are incorrect. :p


The wiring of a mobile home is no different than the wiring of a detached garage fed from a dwelling unit.

The service is remote, the panel is a sub panel and this separate structure requires grounding electrodes. :p

[ August 14, 2005, 06:18 AM: Message edited by: iwire ]
 
D

dillon3c

Senior Member
Re: Mobile Home

Bob,
I think the misconception here in defining the term "Mobile Home",as dealing with the conception of "separate stucture".

The meter and service equipment are considered permanent.The Mobile home itself,is not by definition.

*Mobile Home:
A factory-assembled structure or structures transportable in one or more sections that is built on a "permanent chassis" and designed to be used as a dwelling without permanent foundation ]

* For the purpose of the code and unless otherwise indicated the term mobile home includes manufactured homes.

The service structure afixed no more than thirty-foot away, and not mounted on the mobile home , is considered the permanent structure.(Not the Mobile Home)~per 550.32~"Grounding of the disconnecting means shall be shall be in accordance with 250.32

Even installed on foundation,with the axles removed the current code (NEC) does not admend to the term,*Mobile Home.

Differant in term to,"Manufactured Home" that is (without a permanent chassis)- but built on a chassis and designed to be used as a dwelling,with or without a permanent foundation.

*Just my opinion mind you,But this might have something to do with the differance in manufactured home,and mobile home and what may be (deemed permanent or fixed).

*Also notice in the definitions of 550,the have a definition for Mobile Home Accessory Building or Structure.-Which could infact back-up the notion of these items added,would could be considered in the nature of permanent or fixed. .

*also in this definition,it is not assocciated with the term of the, Manufactured Home..

*I would believe it comes down to the chassis ,and term "Mobile home" at time of set-up, and don't believe it would be considered or deemed, a separate structure from the fix and permanent service point..
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
Re: Mobile Home

dillon, you have provided no code references to back up your thought that the NEC releases the normal requirements simply because the MH may move.

As an example 250.34 permits Portable and Vehicle-Mounted Generators not to have made electrodes if they are cord and plug connected.

Hardwire a portable generator and you must drive a rod.


Bob

[ August 14, 2005, 09:56 AM: Message edited by: iwire ]
 
P

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Re: Mobile Home

Originally posted by don_resqcapt19:
Bob,
I think that the works "at each" will require a grounding electrode system at each and every structure, and not a common one or multiple structures. I don't see any electrical reason, only a code reason.
Don
Click to expand...
But it does not say that the GE at each structure could not be the same GE, just that there has to be a GE at each structure. One might argue the definition of "at". But it would be hard to argue that a GE within a foot of a structure is not "at" the structure, and if it is connected to another structure a foot away in the other diection, it appears to me the GE is "at" both structures.
 
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jimwalker

Senior Member
Location
TAMPA FLORIDA
Re: Mobile Home

I understand most mobiles are not getting there own rod.But the reason makes no since at all.They are not like RV,S and moving every day or week.They usually are set up for many years or life.How is it that a garage with 2 circuits the same 30 feet away would not be safe without a rod but a mobile is ? Does electric work different on them ? I am with Bob on this one.All other codes are in effect in a mobile unless otherwise changed in 550.Please cite the number that allows no ground rod.Of all the places that need protection i would think a mobile should be on the top of the list.

The pole and mobile are 2 seperate stuctures,otherwise you can't put the service on the pole

[ August 14, 2005, 12:52 PM: Message edited by: jimwalker ]
 
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