Main bonding jumper

[Onydom]

Hello,
My apologies for misunderstanding, i am in the field. I just put a triple wide trailer in the mountains. Im leary of putting a main bonding jumper in my panel because its fed by generator only. Ive never been in this application and its my stuff. Seems like the current might ride the GEC instead of returning to the source and id have a hot gr. rod. Im unsure as to leave the gr's & neu.'s seperate and groun the gen. or bond them and be comfortable with two rods. Im concerned with open neautral "wandering electricity".

 

[ActionDave]

You either bond at the panel or bond at the generator and you run an equipment grounding conductor to the place you didn't bond the neutral.

 

[tom baker]

Wandering electricity (current) will not happen, current goes back to its source.
For a SDS, you install the SBJ at the source or first disconnect, the GEC connection is made where ever you install the SBJ. See 250.30

 

[Smart $]

Wandering electricity (current) will not happen, current goes back to its source.
For a SDS, you install the SBJ at the source or first disconnect, the GEC connection is made where ever you install the SBJ. See 250.30

+1

@Onydom
You can only have a Main Bonding Jumper with a service. For other sources of power, a System Bonding Jumper is used.

 

[david]

Hello,
My apologies for misunderstanding, i am in the field. I just put a triple wide trailer in the mountains. Im leary of putting a main bonding jumper in my panel because its fed by generator only. Ive never been in this application and its my stuff. Seems like the current might ride the GEC instead of returning to the source and id have a hot gr. rod. Im unsure as to leave the gr's & neu.'s seperate and groun the gen. or bond them and be comfortable with two rods. Im concerned with open neautral "wandering electricity".

Hello,
I just put a triple wide trailer in the mountains.

Hello,
Im leary of putting a main bonding jumper in my panel because its fed by generator only.

Do you mean the main panel in a manufactured home?

I'm asking because you do not normally bond the neutral in that panel, a manufactured home is normally supplied by a feeder

 

[Smart $]

Do you mean the main panel in a manufactured home?

I'm asking because you do not normally bond the neutral in that panel, a manufactured home is normally supplied by a feeder

Being fed by generator only, it'd have to be feeder supplied. Also, unlike a mobile home, service equipment is permitted to be installed in or on a manufactured home, much like a stick-built home [550.32(B)]. If a manufactured home's supply equipment is the first disconnecting means for an SDS source (generator), it can most certainly contain the system bonding jumper.

However, a generator of sufficient size to handle a triple-wide would likely have the first disconnecting means integral with the generator itself... so the system bonding jumper will have to be located at the generator.

 

[david]

Being fed by generator only, it'd have to be feeder supplied. Also, unlike a mobile home, service equipment is permitted to be installed in or on a manufactured home, much like a stick-built home [550.32(B)]. If a manufactured home's supply equipment is the first disconnecting means for an SDS source (generator), it can most certainly contain the system bonding jumper.

However, a generator of sufficient size to handle a triple-wide would likely have the first disconnecting means integral with the generator itself... so the system bonding jumper will have to be located at the generator.

Point taken in regards to 550.32(B), how ever it has been my experience manufactured home factory distribution panels are greater than 95% feeder supplied. Usually service equipment in a basement or just because the distance between meter and supply passing under the manufactured home.

I was trying to indicate you would not bond the neutral in a feeder supplied distribution panel. Was not sure what panel the OP was referring to.

 

[Smart $]

Point taken in regards to 550.32(B), how ever it has been my experience manufactured home factory distribution panels are greater than 95% feeder supplied. Usually service equipment in a basement or just because the distance between meter and supply passing under the manufactured home.

I was trying to indicate you would not bond the neutral in a feeder supplied distribution panel. Was not sure what panel the OP was referring to.

95% of the time does not justify overlooking the other 5%.

 

[david]

95% of the time does not justify overlooking the other 5%.

Normally:
in general
Usually
More often than not
On average
Generally

 

[kwired]

OP has indicated this is supplied by a generator only. If it were supplied by a service there would be a grounding of the neutral at some point upstream of the home, whether it is immediately adjacent to the home or further upstream (wherever the service disconnect is). If generator is "non separately derived" that grounding at the service is still the same point that bonds the neutral and EGC of the generator together.

With no utility supply whatsoever, that grounding will have to be done either at the generator or at the first disconnecting means.

What you don't want is multiple grounding points on current carrying (neutral) conductors, that does allow for stray current to flow on unintended paths.

 

[Onydom]

Whats up fellas?
Good replies. Yes it is a manufactured home. 200A breaker in the (only) e panel. Ive fed the panel w 3-0
or rather, ive taken the feeders to a nema 3 can 12X12 to the outside of the house where ill set the gen. Ground rods are by the can on outside of manuf. home. Ive ran EGC & GEC from panel to box, GEC hits the can and passes thru to rods unbroken and E.G. is waiting in box for gen. im on a Reservation so i can "get away" with alot, no inspections. But i am code compliant. Seems i'll bond in the panel and ground the gen.

 

[Onydom]

Oh.. also if for some reason the rod(s) do become energized i can't put a hot stick on it and know if its hot nor can i meter it and get a reading , right ? So.. probe it ? To know..? Ive tried(before) to get a reading on neutral conductor installing an exit sign. Got no reading and still got shocked.

 

[Smart $]

Whats up fellas?

You are. Welcome to the forum... :thumbsup:

Good replies. Yes it is a manufactured home. 200A breaker in the (only) e panel. Ive fed the panel w 3-0 or rather, ive taken the feeders to a nema 3 can 12X12 to the outside of the house where ill set the gen. Ground rods are by the can on outside of manuf. home. Ive ran EGC & GEC from panel to box, GEC hits the can and passes thru to rods unbroken and E.G. is waiting in box for gen. im on a Reservation so i can "get away" with alot, no inspections. But i am code compliant. Seems i'll bond in the panel and ground the gen.

Is there a disconnecting means integral with the generator? If so, that would be the first disconnecting means. If not, then it would appear the manufactured home panelboard is the first disconnecting means. Your system bonding jumper is required to be located in the first disconnecting means enclosure.

 

[david]

The OP said he was on a reservation and not subjected to an NEC inspection. Now that the discussion is past a safe way to supply the manufactured home with a generator.

It is my opinion that there is no NEC compliant way to supply a Manufactured home with a supply system that has an un-grounded neutral.

The last ripple wide manufactured home I saw had two distribution panels, Just curious to how many distribution panels this one has.

If either of the above are a consideration you may want (service equipment) exterior of the manufactured home so you could supply the manufactured home with only one grounded neutral feeder.

550.4 General Requirements.
(C) Connection to Wiring System. The provisions of this article shall apply to mobile homes intended for connection to a wiring system rated 120/240 volts, nominal, 3-wire ac, with a grounded neutral conductor.

 

[kwired]

The OP said he was on a reservation and not subjected to an NEC inspection. Now that the discussion is past a safe way to supply the manufactured home with a generator.

It is my opinion that there is no NEC compliant way to supply a Manufactured home with a supply system that has an un-grounded neutral.

The last ripple wide manufactured home I saw had two distribution panels, Just curious to how many distribution panels this one has.

If either of the above are a consideration you may want (service equipment) exterior of the manufactured home so you could supply the manufactured home with only one grounded neutral feeder.

550.4 General Requirements.
(C) Connection to Wiring System. The provisions of this article shall apply to mobile homes intended for connection to a wiring system rated 120/240 volts, nominal, 3-wire ac, with a grounded neutral conductor.

I agree, the neutral should be grounded before the feeder circuit to the home, and anything after the feeder/service disconnecting means that is required to be within 30 ft of the home should be done the same as any other mobile home installation is done.

 

[Smart $]

I agree, the neutral should be grounded before the feeder circuit to the home, and anything after the feeder/service disconnecting means that is required to be within 30 ft of the home should be done the same as any other mobile home installation is done.

Under 550.32(B) the service disconnecting means for a manufactured home is not required to be exterior to it like a mobile home, as it can be in or on the home... subject to the 7 conditions. I do not see why being supplied by alternate source should make the supply disconnecting means exterior like a mobile home. Nonetheless, the disconnecting means will likely be exterior simply because it will be an integral part of the generator.

 

[david]

Under 550.32(B) the service disconnecting means for a manufactured home is not required to be exterior to it like a mobile home, as it can be in or on the home... subject to the 7 conditions. I do not see why being supplied by alternate source should make the supply disconnecting means exterior like a mobile home. Nonetheless, the disconnecting means will likely be exterior simply because it will be an integral part of the generator.

If utility supplied the service supplying the manufactured home (dwelling) is intended to be 240/120 with a grounded neutral conductor.

This is a manufactured home with manufactured instructions the supply to the manufactured dwelling is intended to be 240/120 grounded neutral.

Yes you are allowed to supply a manufactured home with a 240/120 3 wire supply.

You are not allowed to supply the building with a 240/120 volt 3 wire supply and depend on the manufactures equipment to ground the supply system.

The section I posted says the supply system is intended to have a grounded neutral.

The same section makes a distinction that it is intended to be an AC system verses a DC system

 

[Smart $]

If utility supplied the service supplying the manufactured home (dwelling) is intended to be 240/120 with a grounded neutral conductor.

This is a manufactured home with manufactured instructions the supply to the manufactured dwelling is intended to be 240/120 grounded neutral.

Yes you are allowed to supply a manufactured home with a 240/120 3 wire supply.

You are not allowed to supply the building with a 240/120 volt 3 wire supply and depend on the manufactures equipment to ground the supply system.

The section I posted says the supply system is intended to have a grounded neutral.

The same section makes a distinction that it is intended to be an AC system verses a DC system

Article 550 does not say what I've highlighted above.

Article 550 does not say where the system bonding jumper must be located.

 

[david]

Article 550 does not say what I've highlighted above.

Article 550 does not say where the system bonding jumper must be located.

I cannot disagree that the article does not specifically state where the systems neutral is grounded. It does however state that the systems neutral conductor supplying the manufactured home be one that is grounded.

 

[david]

This has been an interesting discussion on how to supply a typical dwelling off grid from a generator.

You can debate if it is an added step in safety to supply a manufactured home from a system having a grounded neutral.

There really is no debate that manufactured homes come with manufactured instructions. Manufactured homes are listed labeled and tested in compliance with those instructions.

Manufactures of manufactured homes do their best to correlate these instructions with the NEC.

I really do not know why we are having a debate about an NEC statement that a manufactured home is intended to be connected to a system supply that has a grounded neutral conductor.

We could just as easily have a discussion if your off grid can you safely supply a manufactured home with a 120 volt system instead of a 120/ 240 volt system.

After the debates are over, it could be pointed out that the Manufactures instructions and the NEC state no you cannot connect to a 120 volt supply if you’re using the manufactured home as a dwelling
550.4 (A) and 550.4(C)