mobile home & ground rods

[david]

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.

(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:

Now your being selective it says that the service equipment shall be permitted to be installed in or on (not the grounding electrode conductor) provided that all of the following conditions are met:

article two 230 would allow the grounding electrode connection to the system neutral in the meter enclosure or any place up an to the service drop or lateral article 230 would also allow the connection to the neutral in the service disconnect enclosure.

However article 550.32 Before you are allowed to install the service in the manufactured home you must rout the groundin electrode conductor out side
For example We know that article 230 allows provision for a connection point the easily would comply connect it to the neutral in the meter enclosure

(1) The manufacturer shall include in its written installation instructions information indicating that the home shall be secured in place by an anchoring system or installed on and secured to a permanent foundation.
(2) The installation of the service shall comply with Part I through Part VII of Article 230.
(3) Means shall be provided for the connection of a grounding electrode conductor to the service equipment and routing it outside the structure.
(4) Bonding and grounding of the service shall be in accordance with Part I through Part V of Article 250.
(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.
(6) The minimum size grounding electrode conductor shall be specified in the instructions.
(7) A red warning label shall be mounted on or adjacent to the service equipment. The label shall state the following:

WARNING
DO NOT PROVIDE ELECTRICAL POWER
UNTIL THE GROUNDING ELECTRODE(S)
IS INSTALLED AND CONNECTED
(SEE INSTALLATION INSTRUCTIONS).

Where the service equipment is not installed in or on the unit, the installation shall comply with the other provisions of this section.

 

[Smart $]

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.

I must have missed something...

When did UL start listing manufactured homes???

 

[jwelectric]

See 550.4(C)
Then back to the rule of, ?if the code don?t say I can?t then I can? and apply it in a different phrase that goes a little like this, if the code don?t say I have to then I don?t?

When connecting to a wiring system the only Article of the NEC that applies if Article 550 and no other unless referenced in 550 such as the last sentence of 550.4(A)

This is my take on this issue and I stand pat on that ground and defend it to my last post on the matter which I just made.

 

[david]

The only way that i would aprove a grounding electrode connected to an interior of a manufacture home if all of the above was provided by the manufacture

In other words the manufacture would have to make a connection to the service enclosure and provide a connection point outside of the structure

 

[jwelectric]

I must have missed something...

When did UL start listing manufactured homes???

It has been a while for me and trailers but the best I remember there is a plate stamped with UL at the entrance point of the feeders.

 

[kwired]

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.

If required to connect the mobile home distribution panel to a GEC then the manufacturer should either provide a place to connect it near these raceways provided for the supply or provice a raceway to run the GEC through. Another thing not brought up although I have never seen - what if the water supply qualifies as a grounding electrode?

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.

In that install you created a parallel EGC with the GEC. May not hurt anything but was not necessary.

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.

As has been mentioned it is not listed by UL, but is approved as is by HUD and does have installation instructions like an appliance does. If those instructions include the connection to a grounding electrode (other than the one at the supply feeder) then you should have to do so, just like an appliance.

 

[Smart $]

(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:

Now your being selective it says that the service equipment shall be permitted to be installed in or on (not the grounding electrode conductor) provided that all of the following conditions are met:

article two 230 would allow the grounding electrode connection to the system neutral in the meter enclosure or any place up an to the service drop or lateral article 230 would also allow the connection to the neutral in the service disconnect enclosure.

However article 550.32 Before you are allowed to install the service in the manufactured home you must rout the groundin electrode conductor out side
For example We know that article 230 allows provision for a connection point the easily would comply connect it to the neutral in the meter enclosure

(1) The manufacturer shall include in its written installation instructions information indicating that the home shall be secured in place by an anchoring system or installed on and secured to a permanent foundation.
(2) The installation of the service shall comply with Part I through Part VII of Article 230.
(3) Means shall be provided for the connection of a grounding electrode conductor to the service equipment and routing it outside the structure.
(4) Bonding and grounding of the service shall be in accordance with Part I through Part V of Article 250.
(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.
(6) The minimum size grounding electrode conductor shall be specified in the instructions.
(7) A red warning label shall be mounted on or adjacent to the service equipment. The label shall state the following:

WARNING
DO NOT PROVIDE ELECTRICAL POWER
UNTIL THE GROUNDING ELECTRODE(S)
IS INSTALLED AND CONNECTED
(SEE INSTALLATION INSTRUCTIONS).

Where the service equipment is not installed in or on the unit, the installation shall comply with the other provisions of this section.

So what happens if manufacturer wires a manufactured home for service to be connected in or on the home... but it is instead supplied by feeder?

Just by your jumping around to different requirements in both the NEC and CFR, I can tell you have not come to a full understanding... and I mean no insult by that statement, but you seem to be beating a dead horse. I have armed you with all the information you need... either you see it or you don't.

 

[kwired]

Mobile home service equipment is not allowed in or on the mobile home - it must be supplied by a feeder. 550.10, 550.32(A).

A manufactured home can have service equipment installed in or on the home. 550.32(B).

I have never seen one with panel in an exterior wall. That would effect the thermal insulating requirements if it were to be placed there. Most of them I have seen are in an interior wall but close to an exterior wall.

 

[hurk27]

Mobile home service equipment is not allowed in or on the mobile home - it must be supplied by a feeder. 550.10, 550.32(A).

A manufactured home can have service equipment installed in or on the home. 550.32(B).

I have never seen one with panel in an exterior wall. That would effect the thermal insulating requirements if it were to be placed there. Most of them I have seen are in an interior wall but close to an exterior wall.

Same here with those PVC conduits shooting down to the underside most cases it's just inside the back door on the interior side wall, by the laundry equipment.

As far as Mobile home verse Manufactured home goes, HUD no longer recognizes a difference and haven't since June, 16, 1986 this is one place that the NEC and CFR24 3280.800 differ, which CFR take precedent over the NEC on.

 

[kwired]

Almost every one of thes homes I have seen probably are truly mobile homes, but there are some that are definately different - There is a place that makes homes not too far from where I live and I would say they are true manufactured homes. They are not built very much different than a home constructed on site, do not have a permantly installed metal under chassis and are intended to be installed on a basement or other permanent foundation. Most work is done in the plant including plumbing, HVAC, electrical. They will even make multistory homes and ship to site in sections and finish putting them together on site.

 

[renosteinke]

UL began listing manufactured homes / mobile homes in 1974 ... they worked together with HUD to develop the standards.

 

[hurk27]

Almost every one of these homes I have seen probably are truly mobile homes, but there are some that are definitely different - There is a place that makes homes not too far from where I live and I would say they are true manufactured homes. They are not built very much different than a home constructed on site, do not have a permanently installed metal under chassis and are intended to be installed on a basement or other permanent foundation. Most work is done in the plant including plumbing, HVAC, electrical. They will even make multistory homes and ship to site in sections and finish putting them together on site.

And those are modular homes, that follow state regulation much different from a HUD certified home, although some of these can be certified by HUD, but this is a choice that the manufacture makes and many do not go this route as it is costly, generally the difference is basically a manufactured home has a permanent steel frame that remains with the home as it is a permanent part of its structure, where a modular has its own structure which is wood beams in most cases and the steel frame it is hauled to the site on goes back to the factory.

In HUD's eyes any mobile home manufactured after June 16, 1986 is in fact a Manufactured home.
If I get time I look on HUD's site to find where they state this.

 

[pfalcon]

Sorry, but I'm still stuck on 550.16 saying that it "shall be through". That sort of eliminates all other paths including 250.

 

[iwire]

Sorry, but I'm still stuck on 550.16 saying that it "shall be through". That sort of eliminates all other paths including 250.

Actually it does not, I agree it hints at it but it does not say it.

Here is just one example of many where a later Article modifies the previous Article.

430.51 General. Part IV specifies devices intended to protect
the motor branch-circuit conductors, the motor control apparatus,
and the motors against overcurrent due to short circuits
or ground faults. These rules add to or amend the provisions of
Article 240. The devices specified in Part IV do not include
the types of devices required by 210.8, 230.95, and 590.6.
The provisions of Part IV shall not apply to motor circuits
rated over 600 volts, nominal.

And beyond that if we look at Article 240 we see it tells us 430 is permitted to change things.

240.4(G) Overcurrent Protection for Specific Conductor Applications.
Overcurrent protection for the specific conductors
shall be permitted to be provided as referenced in Table
240.4(G).

And of course Article 430 is in the table.


Many people seem very sure what the intent is, I do not pretend to know the intent. I do know that in every other instance the NEC seems to be pretty damn anal about grounding electrode systems at all separate building and structures and SDSs and Antennas and ... well I am sure you get what I am saying.


Now the NEC also likes to throw a curve ball at us so I could see the rules changing for a mobile home, maybe there is a real need for the rule to change that I can't see. But ... if they where going to do this I would have expected the wording to be more forceful.

Just my rambling opinion.

 

[renosteinke]

Mobile homes do seem to be a sort of "through the looking glass" world.

For example, how do you size the service? Well, forget about load calculations ... if it has a 200 amp main breaker, you need a 200 amp service. It's that simple - at least as enforced by the mobile home division of the state of Nevada. (Codes says service will not exceed ... the State wants you to match). They also take the position that the home is an appliance, rather than a structure.

This is kind of interesting, as they also want the trailers permanently mounted; whether the trailer is 'real estate' or a 'trailer' is the subject of a lot of zoning and taxing authority fussing.

 

[pfalcon]

Actually it does not, I agree it hints at it but it does not say it.
Many people seem very sure what the intent is, I do not pretend to know the intent. I do know that in every other instance the NEC seems to be pretty damn anal about grounding electrode systems at all separate building and structures and SDSs and Antennas and ... well I am sure you get what I am saying. ...

Okay, but I'm still looking at
shall be :: being a definitive DO IT THIS WAY

Where 430.51 says
add to or amend :: for which amend is vague but "add to" says to keep the original

And 240.4(G) which says
shall be permitted :: which says an acceptable substitution

Maybe I'm just being a little hard-headed :slaphead: but I don't see anything vague about shall be. It seems a bit strongly worded to call it a hint.

 

[pfalcon]

Mobile homes do seem to be a sort of "through the looking glass" world.

For example, how do you size the service? Well, forget about load calculations ... if it has a 200 amp main breaker, you need a 200 amp service. It's that simple - at least as enforced by the mobile home division of the state of Nevada. (Codes says service will not exceed ... the State wants you to match). They also take the position that the home is an appliance, rather than a structure.

This is kind of interesting, as they also want the trailers permanently mounted; whether the trailer is 'real estate' or a 'trailer' is the subject of a lot of zoning and taxing authority fussing.

In Indiana, there are mobile homes, manufactured homes, and mobile homes with permanent foundations. Those are layman terms not legal but change taxes and legal standings. Legal terms aren't as clear. Default lease agreements with mobile homes are closer to hotel agreements by falling under the "Innkeeper" laws rather than "Rental" laws. Except where they don't

 

[iwire]

Okay, but I'm still looking at
shall be :: being a definitive DO IT THIS WAY

It shall be grounded 'this way' does not prohibit or release from being grounded additional ways.

At least that is how I see it.

 

[david]

So what happens if manufacturer wires a manufactured home for service to be connected in or on the home... but it is instead supplied by feeder?

Just by your jumping around to different requirements in both the NEC and CFR, I can tell you have not come to a full understanding... and I mean no insult by that statement, but you seem to be beating a dead horse. I have armed you with all the information you need... either you see it or you don't.

Like just about any service rated panel there will be a removable bond between the eguipment ground and the nuetral
and I am sure the instructions would indicate what you would do in that case.



I don't know what your talking about i mention the fair housing act and Hud hving jusidiction over the structure and instruction on one method of grounding

Could you please show me one reference i made that was not from the NEC

 

[Smart $]

I don't know what your talking about i mention the fair housing act and Hud hving jusidiction over the structure and instruction on one method of grounding

Could you please show me one reference i made that was not from the NEC

My mistake... sorry :hug:

Like just about any service rated panel there will be a removable bond between the eguipment ground and the nuetral and I am sure the instructions would indicate what you would do in that case.

That would be a start, but what I'm getting at is...

550.33 Feeder.

(A) Feeder Conductors. Feeder conductors shall comply
with the following:

(1) Feeder conductors shall consist of either a listed cord,
factory installed in accordance with 550.10(B), or a
permanently installed feeder consisting of four insulated,
color-coded conductors that shall be identified by
the factory or field marking of the conductors in compliance
with 310.12. Equipment grounding conductors
shall not be identified by stripping the insulation.

(2) Feeder conductors shall be installed in compliance with
250.32(B).

Exception: [omitted for brevity].

Now for the clincher...

250.32 Buildings or Structures Supplied by a Feeder(s)
or Branch Circuit(s).

(B) Grounded Systems. For a grounded system at the
separate building or structure, an equipment grounding conductor
as described in 250.118 shall be run with the supply
conductors and be connected to the building or structure
disconnecting means and to the grounding electrode(s). The
equipment grounding conductor shall be used for grounding
or bonding of equipment, structures, or frames required
to be grounded or bonded. The equipment grounding
conductor shall be sized in accordance with 250.122.
Any installed grounded conductor shall not be connected
to the equipment grounding conductor or to the grounding
electrode(s).

Exception: [omitted for brevity].

Now you can go to 250.32(A) for the electrode requirements. :angel: