mobile home & ground rods

[kwired]

Don, I agree with you, and that's certainly what I've been doing ... letting the EGC of the feeder provide the connection to the grounding network of the main building.

Yet, this very forum, quite recently, said differently. I believe it was Bob (Iwire) who led the charge - that the NEC prohibits the use of the EGC as part of the GEC connections. That leaves us with the necessity of running another ditch, just to connect the electrodes.

That's why I connected these different assertions to this example of the mobile home .... to highlight the absurdity of the concept. I can hardly wait for the HI forums to discover this "error" in every home with a detached garage, every pedestal installation, etc.

On the detached garage situation I think it is pretty clear. The separate building or structure must have its own grounding electrode system, and does not need to run all the way to the building or structure that contains the service, it just needs to run to the main disconnect for the separate building and be connected to the equipment grounding conductor at that point. The issue here is whether or not the pole/pedestal and the mobile home are separate structures or not, as far as the NEC is concerned for purposes of supplying power to a mobile home.

If you did have to bring the grounding electrode conductor from the home to the disconnect why would it need to be in a separate ditch? Why would it or the feeder need to be underground? I do agree that underground is the best way to do it most of the time but do not feel it has to be underground either.

 

[iwire]

It may be just me but it seems we are all talking about different things.

Here is how I see it.


Lets say we have a service at a pole, with a grounding a electrode system, from there a feeder to a home with a second grounding electrode system and finally a feeder from the home to a garage with third grounding a electrode system. (No mobile home in my example)

• The code requires a grounding a electrode system at all three locations
• The code does not require all three grounding electrode systems to be directly connected together with a bonding jumper
• By default they are all connected together via the EGCs.

Do we agree on the above?

 

[kwired]

It may be just me but it seems we are all talking about different things.

Here is how I see it.


Lets say we have a service at a pole, with a grounding a electrode system, from there a feeder to a home with a second grounding electrode system and finally a feeder from the home to a garage with third grounding a electrode system. (No mobile home in my example)

• The code requires a grounding a electrode system at all three locations
• The code does not require all three grounding electrode systems to be directly connected together with a bonding jumper
• By default they are all connected together via the EGCs.

Do we agree on the above?

I totally agree with that. My only question as I have mentioned a couple times in this thread is whether or not the disconnect required within 30 feet of the mobile home is considered a separate structure or if it is considered a part of the mobile home. No code section that I am aware of specifically says either way.

Another similarity would be a stand alone piece of equipment located in a field, lot, etc. Run a service or feeder to a pole/pedestal/other for a disconnect for this piece of equipment. Now run underground either 2 feet or 30 feet and emerge at or under the piece of equipment. Is the pole/pedestal/other a separate structure from the piece of equipment and require a grounding electrode system for both?

How about stand alone equipment located outdoors but is connected to other stand alone equipment or other buildings via piping, conveyors, etc? I run into that a lot and seldom treat them as separate structures they are just extensions of the process of the entire plant/facility.

 

[iwire]

My only question as I have mentioned a couple times in this thread is whether or not the disconnect required within 30 feet of the mobile home is considered a separate structure or if it is considered a part of the mobile home. No code section that I am aware of specifically says either way.

I saw you mention that but I did not answer because I really did not understand. In my opinion per the NEC definition of structure the disconnect is one.

Another similarity would be a stand alone piece of equipment located in a field, lot, etc. Run a service or feeder to a pole/pedestal/other for a disconnect for this piece of equipment. Now run underground either 2 feet or 30 feet and emerge at or under the piece of equipment. Is the pole/pedestal/other a separate structure from the piece of equipment and require a grounding electrode system for both?

I my opinion it is a structure and as far as separate well, is it or not? If they are only connected by the earth supporting them and the conductors between them I would call them separate

How about stand alone equipment located outdoors but is connected to other stand alone equipment or other buildings via piping, conveyors, etc? I run into that a lot and seldom treat them as separate structures they are just extensions of the process of the entire plant/facility.

Great example, I would say they are not separate.

How an of this really makes a difference electrically I have no idea. I am just going with what I consider to be a very literal interpretation of the code.

 

[hurk27]

Just one question, does an RV fit the definition of a structure?? What does 551 say that allows us to ignore 230.32??? If a mobile home was put on a permanent foundation I would agree with the ground rod issue, as we would also allowed to install the service to it, but as long as it remains a structure intended to be moved then I can't see the rod requirement??? I have never been required to install a rod at the trailer only at the disco or service which ever is the closest.

 

[kwired]

The feeder to a mobile home is permitted to be a cord and plug also. Kind of reaffirms the "mobile" in mobile home.

 

[david]

(5) The manufacturer shall include in its written installation instructions one method of grounding the service equipment at the installation site. The instructions shall clearly state that other methods of grounding are found in Article 250.

As to whether the pedestal structure is to be consider by the NEC as part of the manufacture home there by making the feeder not between two separate structures or not I am not sure. As i stated before I believe the instructions are clear in 550.16 (not just intent But instructions) how this is to be accomplished for mobile homes

It is clear to me that the manufacture does reach out to the site grounding at least giving instructions on one safe method to do the site grounding at the manufactured home. So the manufactures arm does reach out at least that far.

Am I the only one noticing that the grounding electrode conductor cannot be installed interior of the manufactured home?

So if you guys are stating that an inspector must mandate this connection to the interior panel shouldn?t there at least be some insight given on how this is to be done to avoid the apparent hazard of routing this interior of the manufacture home.

 

[hurk27]

(5) The manufacturer shall include in its written installation instructions one method of grounding the service equipment at the installation site. The instructions shall clearly state that other methods of grounding are found in Article 250.

As to whether the pedestal structure is to be consider by the NEC as part of the manufacture home there by making the feeder not between two separate structures or not I am not sure. As i stated before I believe the instructions are clear in 550.16 (not just intent But instructions) how this is to be accomplished for mobile homes

It is clear to me that the manufacture does reach out to the site grounding at least giving instructions on one safe method to do the site grounding at the manufactured home. So the manufactures arm does reach out at least that far.

Am I the only one noticing that the grounding electrode conductor cannot be installed interior of the manufactured home?

So if you guys are stating that an inspector must mandate this connection to the interior panel shouldn?t there at least be some insight given on how this is to be done to avoid the apparent hazard of routing this interior of the manufacture home.

Here in Indiana many are manufactured with a 1 1/2" or 2" PVC conduit to the underside for the feeders and some will even have a 1" to the underside for other usage whether it be for AC hook up or what ever, but I still have never been required to install a ground rod at the trailer except one time when one was set on a block foundation with a basement to which we also installed a permanent service.

While most on here know my feelings of how useless a ground rod is, I still do not see it for a home that is in many cases expected to be moved, and around here they do get moved from park to park allot.

 

[david]

Wayne,
Not one electrical inspector in this whole region every required any electrodes connected to one.

Not one electrician as far as I know connects one

I have inspected and been in just about every mobile home park aroumd here (about 30) and never seen one done that way. Most of the inspections are re-meter inspections for these so that means they where originally inspected and have been inspected four or five times since the first inspection.

As a side note the first service I wired was to one the service disconnect was on a pole 10 feet from the manufactured home. I took the grounding electrode conductor from the service disconnect continuous connected two rods 8 ft apart then connected to the frame of the trailer. The inspector scratched his head said never heard of anyone grounding a mobile home before scratched his head again and said can?t see how that will hurt anything just don?t understand why you wasted the wire.

 

[Smart $]

Only if you ignore that 550.16 is specific to mobile homes and the portion posted tells us how to ground a main distribution panel in a mobile home when supplied by a feeder.

Granted 550.16 is specific to mobile homes... but it only supplements Article 250 requirements, as noted in 90.3. Though it could, in no way does it actually modify any Article 250 requirement. As such, 250.32 requirements are not relinquished for Article 550 installations.

]• Yes... and your point???
The only time a grounding electrode conductor is mention in article 550 is when the service equipment is allowed in or on a manufactured home. And there are specific instructions on how the conductor is to be routed when it is associated with a manufactured home,

...and again, it only supplements Article 250 requirements, it does not modify any.

That said, once you understand the entirety of the NEC grounding requirements, you will realize that a GES is required for every separate structure, whether supplied by service or supplied by feeder. There is nothing in Article 550 or CFR Title 24 Subpart I that specifically relinquishes this GES requirement.

There are no such instructions when the supply involves a feeder
Why because article 550 does not require a grounding electrode conductor to the main distribution panel in a manufactured home unless that distribution panel is also the service disconnect for the manufactured home.

Yes, there are instructions. But they are not in Article 550. Article 550 is not the sole instruction for an electrical supply installation of a mobile or manufactured home. Please refer again to 90.3 (and CFR 24 3280 PartI).

Also note that you referenced CFR 24 3280.803(K)(3) which initially states, "Service equipment installed on the manufactured home in accordance with Article 230 of the National Electrical Code, NFPA No. 70–2005, and the following requirements: ..." in an attempt to say the GEC requirement only applies to services connected directly. WHat you took out of context here is that the main paragraph, (k), states, "(k) Where the calculated load exceeds 50 amperes or where a permanent feeder is used, the supply shall be by means of: ..." ...???

The NEC must consider there to be a hazard involved in routing a grounding electrode conductor on the interior of a manufactured home. The only way to connect a grounding electrode conductor to an interior distribution panel is to route it in the interior of the manufactured home.

TTBOMK, all service equipment installed in a mobile/manufactured is installed flush in an exterior wall. The argument that you cannot install a GEC that is completely exterior to the living area will not fly with me.

So lets ignore the fact that the NEC intended an insulated equipment ground to be the connection from the distribution panel to the grounding electrode at the service, or if the service is directly associated with the structure to route it on the exterior of the structure

I am not and will not ignore anything Code related.

 

[paul]

I fail to see where 550.32 removes of the requirement of a grounding electrode system at the mobile home. I'm with Bob on this one.

 

[david]

Granted 550.16 is specific to mobile homes... but it only supplements Article 250 requirements, as noted in 90.3. Though it could, in no way does it actually modify any Article 250 requirement. As such, 250.32 requirements are not relinquished for Article 550 installations.

90.3
Chapters 1 through 4 apply except as amended by Chapters 5, 6, and 7 for the particular conditions.
It is your opinion that 550.16 only supplements and does not amend the way a manufacture home main distrubution panel is connected to a grounding electrode system. You are in titled to that.

 

[Smart $]

Granted 550.16 is specific to mobile homes... but it only supplements Article 250 requirements, as noted in 90.3. Though it could, in no way does it actually modify any Article 250 requirement. As such, 250.32 requirements are not relinquished for Article 550 installations.

90.3
Chapters 1 through 4 apply except as amended by Chapters 5, 6, and 7 for the particular conditions.

It is your opinion that 550.16 only supplements and does not amend the way a manufacture home main distrubution panel is connected to a grounding electrode system. You are in titled to that.

Yes, it is of course my opinion. But that opinion is based on and completely agrees with fact :happyyes:

If 550.16 or any other Article 550 requirement stated something to the effect, "A grounding electrode system at a mobile or manufactured home shall not be required when supplied by a feeder", then I would agree with you.

 

[iwire]

If 550.16 or any other Article 550 requirement stated something to the effect, "A grounding electrode system at a mobile or manufactured home shall not be required when supplied by a feeder", then I would agree with you.

That is what I am looking for and maybe even something at 250.32 that says 'except as allowed elsewhere in this code'

 

[david]

[QUOTE
That said, once you understand the entirety of the NEC grounding requirements, you will realize that a GES is required for every separate structure, whether supplied by service or supplied by feeder. There is nothing in Article 550 or CFR Title 24 Subpart I that specifically relinquishes this GES requirement..[/QUOTE]

That?s kind of brazen of you but never the less, Congratulations on being so smart yourself.

My self I am still learning, but I did however start studying back in 1980 at fort Sill Ok as a fire direction specialist taking correspondence courses studying the national electric code,

I also have the benefit of being surrounded by bright individuals who have in there own right excelled and are dedicated building officials and electrical inspectors.

Keep an open mind I have a whole stack of IAEI magazines dating back to the early 90?s. I visit barnes and noble I have spent over $1500.00 in reference materials this year alone, Though I given my life to this trade have over twenty years experience wiring and been an electrical inspector since 1990. Maybe I am just not as smart as you are


Buy the way I can?t spell worth crap and I?m not afraid to admit that.

 

[david]

TTBOMK, all service equipment installed in a mobile/manufactured is installed flush in an exterior wall. The argument that you cannot install a GEC that is completely exterior to the living area will not fly with me.


550.32 Service Equipment.
B) Manufactured Home Service Equipment. The manufactured home service equipment shall be permitted to be installed in or on a manufactured home, provided that all of the following conditions are met:
(3) Means shall be provided for the connection of a grounding electrode conductor to the service equipment and routing it outside the structure.

Weather it will fly with you or not please recognize it does not say exterior of the living area it say outside of the structure to me that does not include a exterior wall

 

[david]

“Also note that you referenced CFR 24 3280.803(K)(3) which initially states, "Service equipment installed on the manufactured home in accordance with Article 230 of the National Electrical Code, NFPA No. 70–2005, and the following requirements: ..." in an attempt to say the GEC requirement only applies to services connected directly. WHat you took out of context here is that the main paragraph, (k), states, "(k) Where the calculated load exceeds 50 amperes or where a permanent feeder is used, the supply shall be by means of: ..." ...???”

550.10
(I) Mast Weatherhead or Raceway. Where the calculated load exceeds 50 amperes or where a permanent feeder is used, the supply shall be by means of either of the following:

(I) (1) & (2) are both feeders I don’t think I referenced CFR 24

550.32 Service Equipment.
( B) Manufactured Home Service Equipment. The manufactured home service equipment shall be permitted to be installed in or on a manufactured home, provided that all of the following conditions are met:

I do remember making reference to 550,32 (B). And I stand by my statement that the only time in article 550 a grounding electrode conductor is mention in connection with the manufactured home It’s self, is when the service equipment is on or in the manufactured home.

 

[Smart $]

...

Weather it will fly with you or not please recognize it does not say exterior of the living area it say outside of the structure to me that does not include a exterior wall

It says in or on, meaning interior or on exterior respectively. 550.32(B)(2) states "The installation of the service shall comply with Part I through Part VII of Article 230."... and what that means is that when installed inside, it must be nearest the point of entrance of the service conductors. Manufacturers usually put the panel in an exterior wall to make compliance easy. Otherwise, the installation would have to consider methods enumerated in 230.6 Conductors Considered Outside the Building.

 

[Smart $]

That said, once you understand the entirety of the NEC grounding requirements, you will realize that a GES is required for every separate structure, whether supplied by service or supplied by feeder. There is nothing in Article 550 or CFR Title 24 Subpart I that specifically relinquishes this GES requirement..

That?s kind of brazen of you but never the less, Congratulations on being so smart yourself.

My self I am still learning, but I did however start studying back in 1980 at fort Sill Ok as a fire direction specialist taking correspondence courses studying the national electric code,

I also have the benefit of being surrounded by bright individuals who have in there own right excelled and are dedicated building officials and electrical inspectors.

Keep an open mind I have a whole stack of IAEI magazines dating back to the early 90?s. I visit barnes and noble I have spent over $1500.00 in reference materials this year alone, Though I given my life to this trade have over twenty years experience wiring and been an electrical inspector since 1990. Maybe I am just not as smart as you are


Buy the way I can?t spell worth crap and I?m not afraid to admit that.

I admit I am knowledgeable in some matters, but not all, and I always try to have an open mind. I am not a condescending person. Just trying to help by passing on what I know.

 

[renosteinke]

Well, I am glad we cleared up that silliness of not using the feeder EGC as the way to connect different grounding electrode systems together.

As for the trailer needing a ground rod ... I'm still a bit stumped. Sure, it's clearly a 'structure' to my eyes, and ought to require one ... but the thing is listed as is, and there's no provision for connecting a GEC.

All I can figure is that a mobile home is seen as an appliance, and not as a structure. To UL, it's just a fancy toaster.