Mobile Home

[jwelectric]

Re: Mobile Home

Jw, did you read Mike Holts comments, one of which is, to read the definition of Building and Structure in article 100?

Yes I did, I try to read and understand every post in a thread that I am responding to.

Do you really think his material or anyones material can show every possibillity of a "Structure" ?

No, but if any one of these smart people thought that mobile home or RV should have a ground rod driven at them don?t you think at least one of them would have used one or at least made mention of it at some point in time?

Now, the bottom line is, CMP 19 says that under 550.32(A) the grounding requirements for mobile home lot service equipment do not differ from grounding requirements for service equipment installed in or at any other occupancy.

Then you haven?t read 550.32(A) nor 550.32 (D).

550.32 (A) clearly states that the service for a mobile home is to be adjacent to the mobile home and not mounted in or on the mobile home.
This service is allowed to be located elsewhere on the premises, as long as a disconnecting means is located within sight from and not more than 30 feet from mobile home.
This disconnecting means is allowed to be grounded accordance with 250.32.

550.32 (D) Additional Outside Electrical Equipment. Means for connecting a mobile home accessory building or structure or additional electrical equipment located outside a mobile home by a fixed wiring method shall be provided in either the mobile home service equipment or the local external disconnecting means permitted in 550.32(A).

As is pointed out in these two sections of 550 a separate disconnect can be grounded by 250.32 and any additional outside electrical equipment is to be grounded by 250.32. There is nothing that would make me believe that a second rod would be needed here.

550.16 tell how the grounded (neutral) and equipment grounding conductor MUST be connected in the distribution panel on the inside. There is no mention on how to connect a grounding electrode conductor mentioned here so therefore it is not allowed in this panel.

Where does either 550 or 250 state that this ground rod is to be connected?

 

[iwire]

Re: Mobile Home

Here is a good example of Article 550 modifying other code sections.

550.18 Calculations.
The following method shall be employed in computing the supply-cord and distribution-panelboard load for each feeder assembly for each mobile home in lieu of the procedure shown in Article 220 and shall be based on a 3-wire, 120/240-volt supply with 120-volt loads balanced between the two legs of the 3-wire system.

Here there is no question that the rules of 220 take a back seat to the rules of 550.

There is no such wording in 550.16.

550.16 Grounding.
Grounding of both electrical and nonelectrical metal parts in a mobile home shall be through connection to a grounding bus in the mobile home distribution panelboard. The grounding bus shall be grounded through the green-colored insulated conductor in the supply cord or the feeder wiring to the service ground in the service-entrance equipment located adjacent to the mobile home location. Neither the frame of the mobile home nor the frame of any appliance shall be connected to the grounded circuit conductor (neutral) in the mobile home. Where service equipment is installed in or on a manufactured home as permitted in 550.32(B), the neutral conductors and the ground bus shall be permitted to be connected in the distribution panel.

We must follow the rules in 550.16 and because the rules in 550.16 are not "in lieu of" Article 250 they are in addition to the rules in 250.

As far as 550.32(A), all that tells us is that the service is not to be located on the mobile home, period.

It does not tell us that this remote service is the same structure as the mobile home it serves.

It does not tell us "in lieu of article 250"

Do not read into 550.32 what is not there.

Bob

[ August 17, 2005, 07:17 PM: Message edited by: iwire ]

 

[don_resqcapt19]

Re: Mobile Home

While 550.32 is not explicit, I don't believe that the code requires a grounding electrode at the mobile home when the service equipment is remote from the mobile home. I think that 550.32 does act as a modification to 250.
Don

 

[iwire]

Re: Mobile Home

Originally posted by don_resqcapt19:
While 550.32 is not explicit, I don't believe that the code requires a grounding electrode at the mobile home when the service equipment is remote from the mobile home. I think that 550.32 does act as a modification to 250.
Don

Don, I am glad you jumped in, I am also curious what you base your opinion on?

I see no mention of 250 at all in 550.32.

How have you determined which rules of 550 modify and which rules of 550 supplement chapters 1 to 4?

I asked this question to Mike and now I will ask you.

If I park a MH in my back yard and feed it from my house panel do I need to place electrodes at the MH?

Now if I build a dedicated remote service for it can I remove the rod?

Bob

 

[roger]

Re: Mobile Home

Originally posted by jwelectric:

Now, the bottom line is, CMP 19 says that under 550.32(A) the grounding requirements for mobile home lot service equipment do not differ from grounding requirements for service equipment installed in or at any other occupancy.

Then you haven?t read 550.32(A) nor 550.32 (D).

Well JW, yes I have read all the articles and sections discussed in this thread, I also read the following ROP and CMP 19's Statement for the reason of their rejection of the proposal.

19-63 Log #639 NEC-P19

(550-32(A))

Final Action: Reject

Submitter: Dan Leaf Palmdale, CA

Recommendation:

Add new text to read as follows:

Grounding and bonding at mobile home lot service equipment supplied by service conductors shall be in accordance with Parts II, III, IV, and V of Article 250.

Substantiation: Grounding and bonding at service equipment supplied by service conductors is not specifically noted as is done in (B)(4) for

Manufactured Homes.

Panel Meeting Action: Reject

Panel Statement:

The grounding requirements for mobile home lot service equipment do not differ from grounding requirements for service equipment installed in or at any other occupancy. It is not necessary to provide general references to the parts of Article 250 that apply to the grounding of services.

Number Eligible to Vote: 13

Affirmative: 12 Ballot Results:

Zieman Ballot Not Returned: 1

In the sake of peace, I guess I will leave this thread now, and you can debate CMP 19's intent and your interpretation of the wording (or lack of) with CMP 19 themselves.


Roger

[ August 17, 2005, 08:18 PM: Message edited by: roger ]

 

[jwelectric]

Re: Mobile Home

Well praise the Lord we are discussing the mobile home instead of 250.32.

Now that we have addressed part of 550.16 can we keep on until we have addressed it all?

As outlined by Bob in the 2002 cycle 550.16 states that The grounding bus shall be grounded through the green-colored insulated conductor in the supply cord or the feeder wiring to the service ground in the service-entrance equipment located adjacent to the mobile home location.

Here in 550.16 it states that the grounding bus of the distribution panelboard is to be connected to the grounded (neutral) in the service equipment located outside.
No mention of connecting to a ground rod but a mandatory rule that it MUST connect ot the service equipment.

Now let?s look on down 550.16 to part (B)

(B) Equipment Grounding Means.
(1) Supply Cord or Permanent Feeder. The green-colored insulated grounding wire in the supply cord or permanent feeder wiring shall be connected to the grounding bus in the distribution panelboard or disconnecting means.
(2) Electrical System. In the electrical system, all exposed metal parts, enclosures, frames, lamp fixture canopies, and so forth shall be effectively bonded to the grounding terminal or enclosure of the distribution panelboard.
(3) Cord-Connected Appliances. Cord-connected appliances, such as washing machines, clothes dryers, and refrigerators, and the electrical system of gas ranges and so forth, shall be grounded by means of a cord with grounding conductor and grounding-type attachment plug.

Here is a lot of talk about the equipment grounding conductor but no mention of a grounding electrode conductor.
Let?s look a little more.

(C) Bonding of Non?Current-Carrying Metal Parts.
(1) Exposed Non?Current-Carrying Metal Parts. All exposed non?current-carrying metal parts that may become energized shall be effectively bonded to the grounding terminal or enclosure of the distribution panelboard. A bonding conductor shall be connected between the distribution panelboard and accessible terminal on the chassis.
(2) Grounding Terminals. Grounding terminals shall be of the solderless type and listed as pressure-terminal connectors recognized for the wire size used. The bonding conductor shall be solid or stranded, insulated or bare, and shall be 8 AWG copper minimum, or equivalent. The bonding conductor shall be routed so as not to be exposed to physical damage.
(3) Metallic Piping and Ducts. Metallic gas, water, and waste pipes and metallic air-circulating ducts shall be considered bonded if they are connected to the terminal on the chassis [see 550.16(C)(1)] by clamps, solderless connectors, or by suitable grounding-type straps.
(4) Metallic Roof and Exterior Coverings. Any metallic roof and exterior covering shall be considered bonded if the following conditions are met:
(1) The metal panels overlap one another and are securely attached to the wood or metal frame parts by metallic fasteners.
(2) The lower panel of the metallic exterior covering is secured by metallic fasteners at a cross member of the chassis by two metal straps per mobile home unit or section at opposite ends.
The bonding strap material shall be a minimum of 100 mm (4 in.) in width of material equivalent to the skin or a material of equal or better electrical conductivity. The straps shall be fastened with paint-penetrating fittings such as screws and starwashers or equivalent.

Here we are told how to bond every thing down to the siding on the outside and all of this is to be connected to the grounded (neutral) in the service disconnect but still no mention of a grounding electrode conductor.

Here in 550.16 we have been told what we are to bond to the equipment grounding conductor and that the equipment grounding conductor SHALL be connected to the grounded (neutral) at the service disconnect. I am not allowed to connect a grounding electrode to the distribution panelboard inside a mobile home.

In 550.32 I am told how and when I am allowed to use 250.32. I am not allowed to use it inside the mobile home.

In order to comply with 250.32 where and how do you purpose the grounding electrode conductor be connected to the mobile home?

 

[jwelectric]

Re: Mobile Home

originally posted by Roger
19-63 Log #639 NEC-P19

(550-32(A))

Final Action: Reject

Submitter: Dan Leaf Palmdale, CA

Recommendation:

Add new text to read as follows:

Grounding and bonding at mobile home lot service equipment supplied by service conductors shall be in accordance with Parts II, III, IV, and V of Article 250.

Roger
I don?t think that this debate has very much to do with the service instead it is about a ground rod being required at the mobile home. Sorry Bro. but you missed the boat with this post.

 

[iwire]

Re: Mobile Home

Mike it is pointless to keep repeating ourselves.

We just look at this from different directions, neither of us is going to change.

From my prospective 550.16 does not need mention a GEC as it is already required by 250.32.

Originally posted by jwelectric:
In order to comply with 250.32 where and how do you purpose the grounding electrode conductor be connected to the mobile home?

From my prospective I would land it at the subpanel just as 250.32 describes.

I am not running, and I do not conceded that you are correct, but I will only respond with new info, anyone that may be interested can look back through the thread for my position.

 

[GG]

Re: Mobile Home

Are Roger and Iwire for driving a ground rod at the MH and JWelectric against driving a ground rod at the MH?

[ August 17, 2005, 08:54 PM: Message edited by: GG ]

 

[iwire]

Re: Mobile Home

Originally posted by jwelectric:
Here is a lot of talk about the equipment grounding conductor but no mention of a grounding electrode conductor.

Ah.....so?

Look at 250.110, 250.112, 250.114, 250.116

There is a lot of talk about the equipment grounding conductor but no mention of a grounding electrode conductor.

Does that mean an GEC is not required at a dwelling unit?

There is a reason that 550.16(A)(B)(C) along with my sections from 250 do not mention a GEC.

Those sections are not about GECs.

 

[iwire]

Re: Mobile Home

Originally posted by GG:
Are Roger and Iwire for driving a ground rod at the MH and JWelectric against driving a ground rod at the MH?

Yeah, it's subtle, you gotta read between the lines.

[ August 17, 2005, 09:07 PM: Message edited by: iwire ]

 

[jwelectric]

Re: Mobile Home

Bob
Weather you take a stand on the ground rod is required at a mobile home or not does not relieve the fact that using your code reference in the 2002 cycle 550.16 mandates what SHALL (mentioned 11 times) be connected to the grounding bus and that this grounding bus SHALL be connected to the grounded (neutral) at the service.

Should a grounding electrode conductor be connected to the panel on the inside of the mobile home it would be in violation of 550.16

To carry this thought to reality.
Should this ground rod be with-in a few feet of the service disconnect then there would be a parallel path between the two panels and we all know this is a big NO NO.
I have said in many of a class over the past five years, ?common sense is the best tool any body in the electrical trade could have.? A good example of this would be 680.26 (C)(3)c
Good Night

 

[iwire]

Re: Mobile Home

Originally posted by jwelectric:
Bob
Weather you take a stand on the ground rod is required at a mobile home or not does not relieve the fact that using your code reference in the 2002 cycle 550.16 mandates what SHALL (mentioned 11 times) be connected to the grounding bus and that this grounding bus SHALL be connected to the grounded (neutral) at the service.

Should a grounding electrode conductor be connected to the panel on the inside of the mobile home it would be in violation of 550.16

Again we have a basic disagreement.

I agree the items that say shall must be done however that does not prohibit other items from being connected to the grounding conductor.

At no time in the NEC are we prohibited from providing additional grounding electrodes, voluntary or mandated.

 

[don_resqcapt19]

Re: Mobile Home

Bob,

If I park a MH in my back yard and feed it from my house panel do I need to place electrodes at the MH?

You are not permitted to do that. The mobile home must be fed from a disconnect within 30'. The grounding electrode system would be installed at the disconnect, not the mobile home.

Now if I build a dedicated remote service for it can I remove the rod?

There is no rod to remove.
Don

 

[GG]

Re: Mobile Home

What if he parks his MH within 30' of his house, the house panel is on the outside of the house, and within sight of the MH. Then he could do it, right?

 

[jwelectric]

Re: Mobile Home

Originally posted by iwire:

I agree the items that say shall must be done however that does not prohibit other items from being connected to the grounding conductor.

At no time in the NEC are we prohibited from providing additional grounding electrodes, voluntary or mandated.

So now you have moved from the statement that it is required to be installed to it is a permissive rule.

Thank you for finally addressing those sections that was posted instead of just quoting 250.32 with the attitude that nothing else mattered.

I apologize to you for any attack that you feel that I was making toward you personally. Please understand that it was not directed at you but at the attitude that 250.32 is right just because you said it was.

Any one of the engineers in this forum can attest to the fact that if the ground rod installed at the mobile home was close enough to the required ground rod at the service it could cause a parallel path for a fault current that could have enough resistance to impair the opening of the over current device. It could also cause a hot spot in the earth causing the grass to catch fire. The probability is slim but never the less the chance still exists.

Again I make the statement that sometimes common sense must prevail in order that we protect and safeguard persons and property from hazards arising from the use of electricity.

I have a problem with these words that are sometimes thrown out in order to prove a point. ?this is what the code says? then keep driving the same section and never addressing any other section that is being posted. Where I come from we call this blind ignorance.
A debate is when two people can talk about each others opposing sides one addressing the others. It took six pages before the post made on page one by haskindm was ever addressed. How do others think of this?

 

[GG]

Re: Mobile Home

Originally posted by jwelectric:
Any one of the engineers in this forum can attest to the fact that if the ground rod installed at the mobile home was close enough to the required ground rod at the service it could cause a parallel path for a fault current that could have enough resistance to impair the opening of the over current device.

Ground rods have absolutely nothing to do with opening an over current device. That is not their intention at all. Maybe this is why your having a hard time understanding the point Iwire has been trying to make.

[ August 18, 2005, 10:29 AM: Message edited by: GG ]

 

[dillon3c]

Re: Mobile Home

550.16 Grounding
Grounding of both electrical and non-electrical parts in a mobile home shall be through connection to the grounding bus in the "mobile home distribution panelboard'.

The grounding bus -*shall be- grounded through the green-colored insulated conductor in the supply cord or the feeder wiring to the service ground in the service entrance equipment located adjacent to the mobile home location.

Again, you can't bond the "Grounded Conductor" in a "Mobile Home"..

[ August 18, 2005, 12:16 PM: Message edited by: dillon3c ]

 

[OneWay]

Re: Mobile Home

With all the bickering, what would it hurt to go ahead and drive another ground rod, man you guys are silly. Are you afraid that you may exceed the code here?
:roll:

 

[dillon3c]

Re: Mobile Home

I not afraid of exceeding the code.I have no intention of knowingly being in violation either electrician. I posted the above, for your benefit also OneWay..

Read it REAL CLOSE..See the term in first & second sentance -"Shall Be"- in 550.16..

Then turn to 90.5(A)

I don't think I'd drive the second electrode @ the Mobile home, electrician.

*you got nothing to bond..

[ August 18, 2005, 12:13 PM: Message edited by: dillon3c ]