# mobile home service to bond or not to bond



## rikmac (Mar 15, 2010)

Hello peeps i have been a avid reader of this forum in the past 3 weeks do to the renovation of a mobile home i decided to start. The mobile home in question is 50x10 around 1960ish i dont recall of the top of my head but its pretty old. Anyway i decided to live in it so i ripped out all the old wireing and put in all new stuff then came the panel box.Now in my quest for knowledge i have an answer to the problem but i would like to see if im right before i implement it .I have photo documented my adventure and would like to share if anyone else has the same predicament and cant find anything on it so here is the situation.

1st. 50 feet from the trailor is the meter 2 fuse plugs one 50amp and 1 30amp i think couldnt really read the fuse 

2nd. comming up under the trailor is a 3-Pole, 3-Wire, (NEMA 10-50r receptacle) and another outlet for the 30amp 2 wires no ground ihave questions still about that but has nothing to do with this post 

3rd.The old lug box had the 3 wires ran into it with the 2 hots on a 50amp breaker feeding it 3 20amp breakers feeding the whole place and a side box with a glass fuse feeding power to the hot water heater the box was not bonded to the neutral and had ground running to earth ground 

Now should i bond the new box or not bond it


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## Billy_Bob (Sep 11, 2008)

Bond (James Bond! )...

Seriously, the grounds need to be bonded to neutral at some point. This assures that if a hot conductor touches a ground, then the breaker for that hot conductor will trip.

As to NEC and the new work you did and if any changes need to be made to the meter/outlet? (Someone should be along for that...)


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## nap (Dec 4, 2007)

No, you do not bond the neutral and ground in the panel in the trailer. Your service disconnect is at the pedestal and that is the only place you bond the neutral and grounds.


You should then have a 4 wire feeder from the pedestal to the trailer. The trailer does need ground rods and the ground in the panel is connected to the rods.

you do need a grounding electrode system for the pedestal as well.


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## Stubbie (Jan 7, 2007)

First nap is absolutely correct with his advice. Second please take us on your photo adventure including the fuse panel out at the meter because I have 101 questions about what was existing and what is going to be new. You say you are replacing everything with new so I am assuming that also means the service equipment panel out at the meter pedestal and the wire from meter and service equipment to the mobile home trailer 50 amp receptacle. As Nap said you need 4 wires (H-H-N-Grd) from the service equipment at the meter power pedestal to the 50 amp receptacle not 3 like you say you have now. And there should not be an extra 30 amp receptacle feeding power into the trailer. You say you have a 50 amp fuse and a 30 amp fuse at the meter service equipment. They should both be 50 amp if that trailer is being fed a 120/240 volt service.

I hate coming behind people and their trailer (mobile) homes some of the screwest...cheesiest wiring I have ever encountered was with these portable dwellings.....


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## rikmac (Mar 15, 2010)

maby i should have clarified a little i will not be replaceing the wiring or meter from the meter to the trailer (little bit out of my comfort zone ) and anyways i would think the park would be in charge of that . the plugin is a 3 prong not 4 right now. my photo montage will come later tonight im at work now 
the 30 ft that ran under the trailor from th plug in is interesting i think it is like 4 gauge aluminum wire connected to 6/3 copper at the back of the trailer where it came in and connected to the panel.ill have to get a pick of the meter and stuff didnt think of the 2 fuses for the 240 volt make me wonder where those 2 wires are comming from :laughing:


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## kbsparky (Sep 11, 2008)

nap said:


> ..... The trailer does need ground rods and the ground in the panel is connected to the rods.......


I have never installed ground rods at a mobile home. Care to provide a _Code_ section to back up this assertion?


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## rikmac (Mar 15, 2010)

alright gonna try to post some pics

first should be ground pole and the mysterious plug wires 


next is the plug that brings power to the trailer


here is the infamous breaker box


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## rikmac (Mar 15, 2010)

ground wires running to the plug :laughing:


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## nap (Dec 4, 2007)

kbsparky said:


> I have never installed ground rods at a mobile home. Care to provide a _Code_ section to back up this assertion?



is there some reason 250.32 would not apply that you are aware of?


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## Stubbie (Jan 7, 2007)

I think the only way a ground rod is used is if the mobile home service equipment is more than 50 feet from the mobile home and a service rated disconnect is installed between the home and the service equipment but not more than 30' from the home. In which case you would use grounding in accordance with 250.32 at the disconnect location. Otherwise no ground rod at the mobile home panel.


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## nap (Dec 4, 2007)

I don't see anything in 250.32 or anything in 550.xx that would allow that exception Stubbie. If you have some specific sections that you believe would allow this, please post them.


250.32 clearly states that all separate buildings fed through a branch circuit or feeder, unless there is only a single branch circuit (including MWBC) must have a grounding electrode.

the trailer is a separate building or structure simply by virtue of it not being physically connected to the power pedestal. Since there is a distribution panel in the trailer, it is being fed with a feeder and not a branch circuit.


I see no reason why 250.32 would apply to this situation any differently than a situation where you would have a farm stand service and feeders to separate buildings or structures.


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## Billy_Bob (Sep 11, 2008)

This is an interesting situation in that the mobile home is owned, and the plug in and meter are rented!

And that the mobile home is "plugged in" like an appliance, and in other cases like this, that is where the NEC ends and UL begins...

So I searched google.com and found this which apparently covers the electrical in manufactured homes?...

["Any Manufactured Home, Mobile Home, Park Model or Travel Trailer, moved to or within Coconino County for set-up and used for habitation for residential purposes shall have affixed upon it the proper Arizona Identification for Manufactured and Mobile Homes, showing it to be an Approved HUD unit, or the proper American National Standard Institute (ANSI) Label for Park Models and Travel Trailers. (UBC 101 and in accordance with the Coconino County Zoning Ordinance)."]

http://www.coconino.az.gov/uploadedFiles/Community_Development/MH Pre-HUD Memo and checklist.pdf​


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## Stubbie (Jan 7, 2007)

I can't say there is any specific in the nec under art.550 that specifies a ground rod cannot be or must be or is not installed at the mobile home panel board. My understanding is that you do not in order to facilitate the "mobile" aspect of the home. In other words you can unplug the thing and hook up to it and drive away with the home.

My interpretation of 550.16 which also includes the non energized electrical parts and metal frame for equipment grounding and 550.32(A) is that no ground rod is installed at the mobile home panel. The service equipment for the mobile home ... which is specifically not allowed to be attached to the mobile home to keep it mobile has the only ground rod.

I'm certainly no expert on mobile homes but I have done a few and I have never encountered or installed a ground rod and grounding conductor to the inside grounding bar in the distribution panel of the mobile home. Our county guidelines do not require it and it isn't wanted by our inspectors. 

I do not think it is not allowed if you wanted to install one. I also do not think 250.32 applies to mobile homes other than the disconnecting means located outside not attached to the mobile home.


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## wirenut1110 (Apr 26, 2008)

I've never done ground rods at a mobile home either, just at the service. 4 wire to the "trailer" panel and at least a #8 copper bond to the frame.

Most mobile homes have the rods with the strapping that anchor it the ground. I believe that's what's taking place of grounds rods and to how those are attached to the frame.


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## nap (Dec 4, 2007)

Stubbie said:


> I can't say there is any specific in the nec under art.550 that specifies a ground rod cannot be or must be or is not installed at the mobile home panel board. My understanding is that you do not in order to facilitate the "mobile" aspect of the home. In other words you can unplug the thing and hook up to it and drive away with the home.
> 
> My interpretation of 550.16 which also includes the non energized electrical parts and metal frame for equipment grounding and 550.32(A) is that no ground rod is installed at the mobile home panel. The service equipment for the mobile home ... which is specifically not allowed to be attached to the mobile home to keep it mobile has the only ground rod.
> 
> ...



250.32 simply states "building or structures fed by feeders or branch circuits" I see no way to not include them.

I think the only way you could remove it from the requirement to use one would be to consider the home an appliance and not a building but I think that is pushing it a bit far.

and what 550.16 is speaking to is not bonding the steel frame or the frame of any appliances to the _neutral_ (grounded) conductor if the service entrance eqipment is adjecent to (not connected physically) to the home. It goes on to say that if the panel board inside the home is also considered the service entrance equipment, you must bond the neutral and grounding bus (typical for any service entrance equip)

it also states the the appliance frames and other steel_ must_ be bonded to the _grounding_ bus in the house panel even with a separate service pedestal.

and to 550.32

A (controls if the service equip is not mounted on the building)

says grounding at the disconnecting means shall be per 250.32. It speaks to nothing about grounding for the building itself.

and B states that if the service equipment is mounted on the building, grounding is per 250 just like any other building.

disconnecting or even removing a ground rod would be no more work than installing axles and wheels back onto the unit, removing skirting, installing a hitch and lights. I think that is a pretty weak argument stubbie.:wink:


so, I have yet to hear any argument that a manufactured home should not be considered to be a "building or structure" per 250.32.

but, since you want to consider the temporary point:

do you not drive ground rods for a temporary service such as for a construction site?

If powering temporary office trailers from a farm stand type service at a construction site, do you not drive ground rods?


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## Speedy Petey (Feb 1, 2004)

I have also never installed grounding electrodes for a mobile. I don't consider a mobile home a manufactured home. A mod is a manufactured home. 
I think the NEC agrees since Art 500 is titled _"Mobile Homes, Manufactured Homes, and Mobile Home Parks"_.
Personally I do not consider a mobile home a structure.

Also, 550.32 states that grounding at the disconnecting means shall be in accordance with 250.32. Nothing is said about the panel in the trailer.
All we find about the trailer itself is about bonding.


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## Silk (Feb 8, 2008)

Ground rods have never been required at the mobile home for the same reason that the service equipment is not to be mounted in or on the mobile home ---------- because it is mobile.

The whole point behind this is when a trailer house (mobile home ) is removed from the trailer park or any other place, which is done quite frequently in some areas, the grounding electrode system stays intact. When the next trailer is moved in, there is no need to worry about driving another ground rod or hooking up a GEC.

It is basically connected as a temporary structure, which it is designed to be, it's called a mobile home for a reason, because it is supposed to be mobile (moved).

It's about safety, which is all the NEC is really about, or supposed to be anyways.


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## Stubbie (Jan 7, 2007)

Unfortunately the NEC is seemingly vague about the ground rod issue at the distribution panel board for a mobile home. However you need to ask yourself why do they require service equipment to not be attached to a mobile home? Silk answered this for me.

HUD CFR 3280 sets the standards for mobile homes which are by HUD definition easily transportable housing. The weak argument you talk about is the reason behind the SE and ground rods not being attached to the fixed wiring of the mobile home. 

They are not farm services but nice try .... Farm services are special services however and amend the previous chapters. 

The reason I brought up 550.16 is to point out grounding (not the ges) is through the power cord over the egc to the service equipment (550.32) where it first mentions anything about a ground rod. You will notice there is no mention of a grounding electrode system for the mobile home itself once grounding {550.16(A) thru (C)} has been met. You only need to comply with 550.32(A) at that point as for a ground rod and ges for the mobile home. And notice 550.16 is titled Grounding and no mention of grounding electrode conductor being part of grounding the mobile home electrical system... only grounding for human safety not equipment.

The reason I brought up 250.32 not applying is because of 90.3. You will notice that it says chapters 5,6 and 7 are special occupancies or equipment and modify chapters 1,2,3 and 4. Chapter 5 makes no mention of a ges for the mobile home structure only requirement is at the service equipmnt not attached to the mobile home. 

At service equipment (not attached) is the only place a GES is required by 550.32(A) amending 250.32 IMO. Otherwise I would think that it would mention grounding in accordance with 250.32 is required.

I don't know how else to argue this as the NEC doesn't come out and
say flatly that a ground rod is not required at the mobile home. It does however become very clear about the service equipment for the moible home needs a ground rod.

You will also find if you look on a search engine that a ground rod for the mobile home is never required by any local jurisdiction that I can think of or find. I'll be glad to provide some examples if you wish.

Did I do any better......

Your turn....:wink:


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## nap (Dec 4, 2007)

> [=Speedy Petey;415607]I have also never installed grounding electrodes for a mobile. I don't consider a mobile home a manufactured home. A mod is a manufactured home.


 a manufactured home (per the NEC) is a home built on a permanent frame intended to be set on a permanent foundation.

A modular home does not have a permanent frame, only a temp one for transportation. 




> I think the NEC agrees since Art 500 is titled _"Mobile Homes, Manufactured Homes, and Mobile Home Parks"_.
> Personally I do not consider a mobile home a structure.


then what is a structure to you? How about we use the NEC definition:

that which is built or constructed




> Also, 550.32 states that grounding at the disconnecting means shall be in accordance with 250.32. Nothing is said about the panel in the trailer.
> All we find about the trailer itself is about bonding.[


that's right. I already said that but as the home is a structure, it also must abide by 250.32


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## nap (Dec 4, 2007)

Silk said:


> Ground rods have never been required at the mobile home for the same reason that the service equipment is not to be mounted in or on the mobile home ---------- because it is mobile.


I think you need to read what the definition (in the code 550.2) of a manufactured home versus a mobile home. If there is a permanent foundation, it is a manufactured home. From what I have found so far, if the unit has the axles and tongue removed, is mounted an just about any type of concrete support, is tied down and has skirting installed, it is on a permanent foundation. That means just about every home of this type that I and most likely you have worked on is considered to be (per the NEC as a manufactured home.


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## nap (Dec 4, 2007)

> Stubbie;415639]
> 
> You will also find if you look on a search engine that a ground rod for the mobile home is never required by any local jurisdiction that I can think of or find. I'll be glad to provide some examples if you wish.



sure but since most areas I know of use the NEC, it will be up to local interpretation 


and for fun:




> In June of 1976, the United States Congress passed the National Manufactured Housing Construction and Safety Act (42 U.S.C.), which assured that all homes were built to tough national standards. In 1980, Congress approved changing the term 'Mobile Home' to 'Manufactured Home'.


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## nap (Dec 4, 2007)

Stubbie said:


> The reason I brought up 250.32 not applying is because of 90.3. You will notice that it says chapters 5,6 and 7 are special occupancies or equipment and modify chapters 1,2,3 and 4. Chapter 5 makes no mention of a ges for the mobile home structure only requirement is at the service equipmnt not attached to the mobile home.
> :


that's right, they modify, not replace. Therefore, if there is a different method employed in 5 6 and 7, that is used over 1 2 3 and 4. If there is no alteration in 5 6 and 7, that would mean that what is in 1 2 3 and 4 is still applicable.


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## nap (Dec 4, 2007)

> =Silk;415618]Ground rods have never been required at the mobile home for the same reason that the service equipment is not to be mounted in or on the mobile home ---------- because it is mobile.


Um, you might want to do a bit of reading. The service is allowed to be mounted on a manufacturered home and if you will read what the code defines as a manufacturered home, it most likely will be what you and I are speaking about, not a mobile home.



> The whole point behind this is when a trailer house (mobile home ) is removed from the trailer park or any other place, which is done quite frequently in some areas, the grounding electrode system stays intact. When the next trailer is moved in, there is no need to worry about driving another ground rod or hooking up a GEC.


Oh, so removing the skirting, attaching the axles and wheels and tongue and cutting loose the tiedowns, removing the siding from the ends of the home and then reinstalling all of that is less trouble than driving a couple ground rods?

I don't know how many homes you have near you but I have proabably 500 within 5 miles of me and thousands within 35 miles of me. Once they are placed in a park, they rarely leave.





> It's about safety, which is all the NEC is really about, or supposed to be anyways.


and that is why you place a ground rod at an accessory building and it would serve the same purpose for a manufactured home.


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## Stubbie (Jan 7, 2007)

I think the issue here is going to boil down to whether we have a mobile home /manufactured home as defined in art. 550 or manufactured home as defined in art. 550.32(B) In art. 550 the NEC says for the purposes of this article mobile homes include manufactured homes unless otherwise indicated.

So lets pursue when these two type dwellings suddenly become considered differently.. Maybe then we can reach a consensus cause I certainly understand NAPs steadfastness based on NEC language. Who knows I might even change my mind before this is done....

Ok..so where are the indicated differences? First if the service equipment is not installed on the home or in the home it is a mobile home/manufactured home regardless of whether it is on a permanent foundation or not and regardless of its construction method as per HUD cfr 3280 ..the NEC considers them the same.

A distinction occurs in 550.32(B) where it specifically calls out whether or not the mobile home is treated the same as a manufactured home. Remember by construction and design they are different. Where it has service equipment mounted on or inside the home along with 7 requirements. *All* those being met then if the home is a manufactured home by construction then a ges system is installed as per article 250 or manufacturers instructions. So just being anchored down or on permanent foundation does not make a mobile home a manufactured home falling under article 250 where a grounding electrode system is installed in accordance with article 250.32. 
Point being that all 7 requirements along with the service equipment being mounted on the home or in the home and the home must be a manufactured home not a mobile home as determined by HUD cfr 3280 before 250.32 would apply.

So my opinion is that if the service equipment is not on or in the home it is a mobile home as in 550.32(A) utilizing a cord and plug power hookup and no ground rod required. Whether you want to call it a manufactured home or mobile home at that point is irrelevant since code considers them them the same under those guidelines. But the minute you meet *all* the provisions of 550.32(B) you have separated the common considerstion of the two types of dwellings and are dealing with a manufactured home not a mobile home. And grounding requirements are now allowed to follow art. 250.


If you have a mobile home defined by HUD CFR 3280 you have a mobile home and if that mobile home sits on a permanent foundation or not it is still a mobile home as it is designed to not be on a permanent foundation. An achoring system or sitting on blocks does not make the mobile home a manufactured home under 550.32(B)and therefore is magically treated differently. What I am saying here is if you have a mobile home it cannot fall under 550.32(B) as it is not a manufactured home. It is a 550.32(A) service type dwelling no ground rod required. 

If you have detached service equipment with a 4 wire feeder cord or otherwise to the mobile home or manufactured home it does not fall under 250.32. However as said earlier a manufactured home (not a mobile home) due to construction differences can be separated from a mobile home by 550.32(B) and grounding for a ges changes at that point.

EDIT: IMO There would be no reason for 550.32(B) to call out a difference in grounding requirements if 250.32 was understood to apply from the beginning. As I said earlier there is one other situation where 250.32 is allowed and that is if the service equipment is located farther than the 30 feet set out in 550.32(A) at which point you are required to have a service disconnect within 30 feet of the mobile home. You would set a structure ..ie..pole etc.. and mount a disconnect between the mobile home/manufactured home and service equipment on that pole. You would then provide a ground rod at the disconnect location in accordance with 250.32 but there is not a ground rod at the mobile home/manufactured home in this case either. This arrangement is very common in mobile home parks where it is wanted for the service equipment to be centralized. 

Thats my story and I'm sticking to it.....:yes:


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## Silk (Feb 8, 2008)

The more you type (Nap not Stubbie, I'm a slow typer), the dumber this gets. 

550.2 differentiates between mobile and manufactured homes as to what they were *designed *as. Not as to whether you put skirting or haybales around it, not whether you take the tires and axles of or leave them on. If you want to call all mobile homes as manufactured homes then don't argue with us about it, put a recommendation into the RFPA and tell them you don't believe in the Easter Bunny, the Tooth Fairy or in the Mythical Mobile Home.

Until that time as you can make all the mobile homes disappear with a wave of your magic wand, I think I will believe my own eyes when I pass by a trailer park.

The point is that the Grounding Electrode System shall be independant of the mobile home.

One last point. A mobile home is not a structure. It falls under Chapter 5 and is considered a *Special Occupancy.*

The rules for chapters 1 thru 4 are general. Chapters 5 thru 8 are specialized. The rules in 5 thru 8 supercede the general rules for 1-4. If you are going to use a codebook the first thing you must do is learn how it is organized.


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## nap (Dec 4, 2007)

all one has to do to distinguish between a manufactured home and a mobile home is read the definition in 550.2

no other considerations are needed to determine if it is a mobile or manufactured home for NEC purposes. 

the only real difference I see between a mobile home and a manufactured home is:

a manufactured home is at least 320 sq ft or if less, the manufacturer files a certification required by the regulatory agency (whatever that means)

a manuf home can be designed to be installed on a permanent foundation or not. A mobile home is not intended to be installed on a permanent foundation.

Now, with that said, remember what I had stated comprises a permanent foundation: pads and piers (minimum) for support, skirting, home attached to foundation, axles and wheels removed.

so, how many homes you thought were mobile homes had such a foundation and were over 320 sq ft?





Once you determine what the home is classified as, then you can apply the various rules. You do not use the rules to determine the classification.





> So my opinion is that if the service equipment is not on or in the home it is a mobile home as in 550.32(A) utilizing a cord and plug power hookup and no ground rod required.


there is no requirement the service be installed in or on a manufactured home. Code says it is allowed, not required.


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## nap (Dec 4, 2007)

> The rules for chapters 1 thru 4 are general. Chapters 5 thru 8 are specialized. The rules in 5 thru 8 supercede the general rules for 1-4. If you are going to use a codebook the first thing you must do is learn how it is organized.


right, supersede but if there is no rule in contrast to the common rules of 1-4, they still apply.


as such, we must follow the common rules in the earlier chapters and modify them or alter them if there is a contradicting rule in 5 through 7. There is nothing contradicting putting a ground rod at a manufactured home.




> The point is that the Grounding Electrode System shall be independant of the mobile home.


and that would be what section?

maybe the section of silk is making it up because it does not say that anywhere?



> 550.2 differentiates between mobile and manufactured homes as to what they were designed as.


you need to read it again. a manufactured home can have the same basic design specs as a mobile home or a manuf home can also be designed to be set on a permanent foundation. Size appears to be the most obvious determining factor.



> A mobile home is not a structure. It falls under Chapter 5 and is considered a Special Occupancy.


Now who is being a dullard? Based on that statement of yours, an airplane hanger, a commercial garage, motor fuel dispensing facilities, bulk storage plants and even health care facilities are not structures either as they are all also in chapter 5 as special occupancies.:laughing:


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## Stubbie (Jan 7, 2007)

You know this has been a rather interesting journey and I must say it has caused me to blow a lot of accumulated dust off my brain as far as how the NEC requires mobile/manufactured homes to be treated for grounding electrodes.

I'm finding it very difficult to expose the code language that would emphatically deny the used of 250.32. I only know that we don't install ground rods at mobile homes permanent foundation or not and we do not install service equipment on or in mobile homes. Manufactured homes are actually a little rare around my parts at least I think they are....

I also agree with nap after careful consideration that the biggest difference is size from what I'm reading as we take this excercise into it's final hours or posts I should say. I also think one needs to be careful with mixing modular homes with manufactured homes. The actually differences in construction between a mobile home and manufactured home --are or not that great and appearances a very similar ...it's primarily size and overall dimensions as nap said. However none the less they are different and labeled as to there intended design.

Unfortunately I cannot find that arrow through the heart that says in plain english that a mobile home or manufactured home does not follow 250.32 for the dwelling structure unless 550.32(B) is proven. At least I can't pull it out of article 550 language. I think its there but one has to assume that there are 550.32(A) mobile/manufactured homes and 550.32(B) manufactured homes ... mobile homes not included. 

So the challenge for me is proving how to treat a mobile home / manufactured home that doesn't fall under 550.32(B). But again I find it strange that 550.32(B) is necessary if I am to follow 250.32 unless indicated otherwise in article 550. I am inclined to feel that the intent of the cmp is to follow 550.32(A) unless I am dealing with a 550.32(B) manufactured home and article 250 does not apply otherwise.

For what it's worth the attached is a paste of a mobile home requirement for overhead electrical installation and there is no ground rod at the structure. The mobile home/manufactured home is set on blocks in this case.


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## Silk (Feb 8, 2008)

nap said:


> right, supersede but if there is no rule in contrast to the common rules of 1-4, they still apply.
> 
> But is has been superceded by 550.16 which says "grounding shall be connected through the Equipment Grounding Conductor to the adjacent service equipment"
> 
> ...


 
You still are. And yes they all are special occupancies and not just a normal structure, otherwise they wouldn't have their own section. 

How much easier can this stuff be? It's all spelled out for and still your confused. Maybe the NEC should make a special picture book --- with Big Print for a few people out there.


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## nap (Dec 4, 2007)

> =Silk;415884]You still are. And yes they all are special occupancies and not just a normal structure, otherwise they wouldn't have their own section.


Oh, so now they aren't a_ normal _structure. Very different than your last claim:



> *A mobile home is not a structure. It falls under Chapter 5 and is considered a Special Occupancy*.


:laughing::laughing:

so, since you at least admit you were wrong, I guess it's ok.

a structure is still a structure. 

by the way, the section is 

*"special occupancies"*

not special structures. That means _how_ the structure is used is the point.

maybe you need a pair of glasses and a dictionary. 

read:

occupancy


structure

read them aloud to yourself 100 times each. then look up the definition of each. then maybe you will start to grasp the difference.





> How much easier can this stuff be? It's all spelled out for and still your confused. Maybe the NEC should make a special picture book --- with Big Print for a few people out there.


at least I know the difference between a structure and an occupancy.


by the way, there are probably several thousand manufactured homes in parks and on private land within 35 miles of me (and several thousand more setting at the factories they are made. yes, I live near Elkhart Indiana where millions of the dang things have been made.) and yes, we do put ground rods at a manufactured home that is set on a permanent foundation. I know of no installations that are not on a permanent foundation as it is not legally allowed to leave a manufactured home as a temporary installation in the area. (Michigan or Indiana)

the problem with you silk is you are simply wrong. You have been working on manufactured homes all this time and were totally ignorant of the fact. I doubt anybody has installed a mobile home park anywhere in your area in at least 30 years, if not longer. The last mobile home parks in may area were made in the '60's.


and stubbie;

I told you earlier the difference between a modular home and a manufactured home.

a manufactured home is built on a steel frame that stays in place regardless of how it is installed. It is an integral part of the structure. Manufactured homes receive a HUD certification


a modular home is basically a stick built home, built in a factory in sections and assembled on site. There is no permanent steel frame. There is a steel frame used only for transporting the sections to the home site. The frames are returned to the manufacturer to be used to transport other mod home sections. Modular homes must be built utilizing the building codes of the area the home is to be installed.

wikipedia actually explains the difference fairly well:



> Modular homes vs. mobile homes
> Differences include the building codes that govern the construction, types of material used and how they are appraised by banks for lending purposes. The codes that govern the construction of modular homes are the exact same codes that govern the construction of any site constructed home.* In the United States, all modular homes are constructed according the Inte*rnational Building Code (IBC), IRC, BOCA or the code that has been adopted by the local jurisdiction.
> *Mobile homes (manufactured homes) are constructed according to the HUD Code *and are generally considered lesser quality. The materials are the same as site constructed homes. Wood frame floors, walls and roof is the most typical. Some modulars even included brick or stone exteriors, granite counters and steeply pitched roofs. *All modulars are designed to sit on a perimeter foundation or basement. Mobile homes are constructed with a steel chassis that is integral to the integrity of the floor system*. Mobile homes often require special lenders. Most companies have standard plans. However, all modular buildings can be custom built to a clients specifications. Today's designs include multi-story units, multi-family units and entire apartment complexes. The negative stereotype commonly associated with mobile homes and has prompted some manufacturers to start using the term Off-Site Construction.


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## Leah Frances (Jan 13, 2008)

Ok Fellas - simmer down. This has been intensely instructive so far - and I'm never going to install or service electrical at any location other than my own home (since that's all the law allows me to do...). 

However, this piques my former life as an attorney reading code of all sorts from all sorts of agencies. Wish I had a couple of hours to pick through this from the point of view of a legal analysis. 

Have at it guys - my intuition (as a lawyer and a woman :smartass is that you haven't gotten to the root of it just yet.


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## nap (Dec 4, 2007)

Leah Frances said:


> Have at it guys - my intuition (as a lawyer and a woman :smartass is that you haven't gotten to the root of it just yet.


oh, that's it. stir it up some more:laughing:


and do you still do the lawyer thing? There are a couple forums I hang out that you might have fun with if you still enjoy dealing with that type of thing?


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## Leah Frances (Jan 13, 2008)

Former life. Couldn't pay me enough money to go back to it (though I am a bar member in Oregon). Thanks for asking, though.

Now I am a full-time DIYer remodeling our 205 year old farmhouse and WAY happier/healthier.:thumbsup:


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## Stubbie (Jan 7, 2007)

Hi Nap

I haven't found this easy to argue believe me. All I know at this point is that I cannot find a local installation requirement for the use of 250.32 for a mobile/manufactured home. And this includes those set on blocks with chassis wheels removed, permanent foundation or not. I do agree that the requirement of 550.32(B) is to allow service equipment to be mounted on a manufactured home in which case it would inherit the ground rod requirement at the structure.

My problem is with your assertion that if the mobile home/manufactured home is set on a permanent foundation, wheel axles removed etc it will have grounding in accordance with 250.32 for a structure supplied from the service equipment. I tend to agree with that assertion *but I cannot find in my local codes or any one elses where that is the case. *I posted a drawing showing that to be true. I can show you several more if you like. I just wish I could find the reason in the code language.

I am also assuming that if the mobile home/manufactured home is not on permanent foundation that you are in agreement that a ground rod or ges is not required??

Now where I tend to agree with you is that propety protection doesn't magically change because we have a so called "special occupancy" and therefore there is no need to consider a grounding electrode system whether service equipment is on the mobile home or not. 

It would seem to me that you would be correct and apply 250.32 to a mobile home/manufactured home set on a permanent foundation regardless whether it is designed to be readily removed as defined by HUD. That makes sense to me as you continue to say. You would want property protection just like any other dwelling. And mobile homes/manufactured homes meet the description of any other dwelling/occupancy as far as the NEC is concerned.



Look at 550.32(A) Service equipment is required to not be installed on or in the mobile home and grounding at the "disconnecting means" other than the service equipment is required to follow 250.32.  Note that this is not the disconnecting means of 550.11(A). but you do follow 250.32 for that disconnecting means remote from the service equipment.

But I have to agree with NAP that you would follow the other code sections, specifically 250.32, unless amended in another code section per 90.3. I see no such amendment or distinction set aside in article 550, other than the case of a manufactured home in 550.32(B).

So if I look at 550.11(A) in hopes of finding something about how the required disconnecting means is treated or amended inside the mobile home I find it to say that this equipment will provide a solderless type grounding connector or bar that has enough terminal connections to provide for all grounding conductors. So are they talking about egc's or egc's and gec's. I'm not real sure. Then if I go 550.16 all it talks about is egc connections and neutral and ground separation.

Again nothing that tells me to disregard 250.32 in the case of a mobile/manufactured home on a permanent foundation as to how to handle the structure itself in regards to a grounding electrode. 

Again my problem is I can't find anyone that interprets a requirement that 250.32 be followed for the mobile home structure outside of 550.32(B). I can't find a local installation drawing that shows a ground rod or any other electrode at the structure (permanent foundation or not) connected to the structures disconnecting means of 550.11(A) or to an panel inside the mobile home.

Frankly as Nap has said if you have a mobile home/manufactured home set on a permanent foundation and do not intend to move it why would you not install a ges? Seems to me you would be required to have an electrode in that situation at the structure in accordance with 250.32 no matter where the service equipment is located.

My understanding and experience (limited in this case) has been that a grounding electrode at the service equipment is all that is required for a mobile home/manufactured home with service equipment located remote from the structure but this is not considering a permanent foundation.

So at this point I think NAP is winning this argument for a mobile home on a permanent foundation with remote sevice equipment. I can think of no reason nor find exception in 550 that you would not want an electrode at the structure itself (250.32) and connected to the grounding bar of the distribuiton equipment in that mobile home.

I'm still finding it strange that I cannot find a drawing that shows this electrode ... permanent foundation or not.

_The key may be just exactly what is considered a permanent foundation and I am begining to believe that I am not understanding what that is and the drawings I'm finding are not mobile homes on permanent foundations.
_
HUD 4930 cg makes a statement " this document outlines the requirements for a permanent foundation to convert the mobile home to real property". but I don't want to buy the document to find out what that is...but I did find this...which might be taken from HUD 4930.

http://www.churchillcounty.org/building/forms/conversion_foundation.pdf

So I am starting to belieive if the mobile home is on a permanent foundation and is fed from service equipment remote from the home which I believe is what NAP is saying you would indeed follow article 250 and sub section 250.32. Unfortunately my experience with this best my memory recall ... is the service equipment was always on the the structure when it was set on a permanent foundation like poured concrete or cinder block on a footing. And I'm not sure if I was ever in a mobile home on a permanent foundation as described in the pasted link..... Those I remember were in parks and were fed by permanent feeders if over 50 amps or cord and plug from a pedestal containing the service equipment.. the ground rod best of my recollection was not present at the structure only at the service equipment. But these were not on permanent foundations as described by the posted documentation.

Nap .... before I forget I was not directing my comment about modular vs manufactured at you. I simply thought some of the posters may be 'thinking' modular instead of manufactured. Sorry if you took it otherwise that was not my intention.


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## rikmac (Mar 15, 2010)

i knew this would stir the pot a little. took picks of the panel at the meter 
and will share them later on tonight i know you will enjoy them:thumbsup:


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## wirenut1110 (Apr 26, 2008)

Silk said:


> This Nap guy seems to be a lost cause.
> 
> Nap, are you really a licensed electrician?


I totally rebuke this. This is an open for discussion not just Q & A. I respect Nap's and the other's post. To outright blast Nap for him being in disagreement is totally uncalled for. Yes, he is an electrician and very qualified. Your post was out of line, disagree is one thing but to insult one's knowledge and or qualifications is another.

This post needs to be closed.


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