Single-wide feed from building with its own service

[Joemctag]

Bought 5 acres rural with a farmhouse with a service (meter) and a 10-yr-old metal building with its own service, 200A.
I plan to set up a used, 14 x 70 mobile home near the building ( less than 100’). Temporary ( 3-5 years) while deciding to fix up farmhouse or build new.
The mobile home’s panel is 200A.
Can I feed the mobile home from the building, and if so, what’s the best way?

 

[Mzungu]

Yes, its no problem to feed the mobile home from the sub panel in your metal building. However, it has to be done in a permanent manner, as there is no provision for temporary in the code that I am aware of regarding your situation. Check your loads in the mobile, does it have an electric furnace, as a 200 amp service is otherwise quite large.

 

[mike93lx]

Yep, no problem. It turns out, there is even a wire type called "mobile home feeder", or MHF. 2-2-2-4 is common, which will provide you with up to 90a. What loads will you have in the mobile home? There are larger sizes too, in case you have electric heat or electric hot water.

It's direct Burial so you'll just need conduit above ground.

You'll need two ground rods at the Mobile home, too

 

[Norcal]

Bought 5 acres rural with a farmhouse with a service (meter) and a 10-yr-old metal building with its own service, 200A.
I plan to set up a used, 14 x 70 mobile home near the building ( less than 100’). Temporary ( 3-5 years) while deciding to fix up farmhouse or build new.
The mobile home’s panel is 200A.
Can I feed the mobile home from the building, and if so, what’s the best way?

If a single wide trailer has a 200A panel, that would mean to me it's all electric, if it had gas appliances would not need such a large panel, 100A would be sufficient, MH's are built as cheap is possible they are not going to over build the electrical, I cannot see any inspector allowing a smaller service then 200A if the MH has 200A.

 

[Mzungu]

If a single wide trailer has a 200A panel, that would mean to me it's all electric, if it had gas appliances would not need such a large panel, 100A would be sufficient, MH's are built as cheap is possible they are not going to over build the electrical, I cannot see any inspector allowing a smaller service then 200A if the MH has 200A.

Depends, a lot of mobile homes are custom ordered. The previous owner could have requested an upgraded 200 amp service for any number of reasons, one of which includes having significant electric heating load. OP needs to give more load details.

 

[Joemctag]

Yes. It’s all electric. I guess I could put a propane fireplace, the good, modern ones use outside air for combustion.
Question was more like, do I need a disconnect or anything outside the m.h.? Just splice the MHF to the old, cut feed coming down from the m.h. panel in a large j box?

 

[Mzungu]

Does it have an electric furnace or baseboards?

 

[Joemctag]

I’m looking at the NEC “4-wire to DETCHED building” schematic.
So, my m.h.’s panel would now be a sub panel?
Says disconnect means required at nearest entry point.
A suitable disconnect mounted to a 4x4 p.t. post just outside the outer wall of the m.h.?
And try to be prominent so it could be found in an emergency?

 

[Joemctag]

Does it have an electric furnace or baseboards?

Electric furnace.

 

[Joemctag]

The m.h. isn’t disconnected at its old location (neighbor’s) yet. I guess I want them to leave all the cable going to their old present disconnect/meter ; as long as possible, in other words. So that it reaches my new disconnect with no need to splice?

 

[Mzungu]

I'm working off the Canadian code, but the main breaker in your MH's panel is normally classified as a main disconnect and shouldn't need another one in front of it other than the breaker that will be feeding it from your source. Maybe your local jurisdiction has additional requirements for an exterior disconnect. Not sure on your electric rates there, but those electric furnaces really dig deep into the pocket during the colder months.

 

[mike93lx]

Yes the trailer's panel is now a sub. Needs to have the bonding screw removed and all neutrals and grounds separated, plus two rods.

As long as the wire feeding it now is 4 wire, and it's rated for indoor use, you can run it to your current panel or splice onto it

 

[Joemctag]

I'm working off the Canadian code, but the main breaker in your MH's panel is normally classified as a main disconnect and shouldn't need another one in front of it other than the breaker that will be feeding it from your source. Maybe your local jurisdiction has additional requirements for an exterior disconnect. Not sure on your electric rates there, but those electric furnaces really dig deep into the pocket during the colder months.

Yes, I’m sure. And what’s even worse is that the power company is an electric co-op and electric he electricity’s a lot more expensive than I’m used to. Probably will go with the gas fireplace. Will be using it at least 2 years.

 

[Joemctag]

I’m looking at the NEC diagram again and there are a lot of things I’m seeing that I need to check, like the separate, not connected, neutral bar and equipment grounding bar in the m.h.’s panel.
Guess I should take the cover off and take a picture.

 

[Mzungu]

Yes, I’m sure. And what’s even worse is that the power company is an electric co-op and electric he electricity’s a lot more expensive than I’m used to. Probably will go with the gas fireplace. Will be using it at least 2 years.

I feel your future pain, the house I am in has a 20KW furnace, and a wife who likes temperatures above 75. I have added a woodstove and recently a mini split on the upper and lower level. I'm also in climate zone 6 which can have some pretty cold temps.

 

[Joemctag]

Yes the trailer's panel is now a sub. Needs to have the bonding screw removed and all neutrals and grounds separated, plus two rods.

As long as the wire feeding it now is 4 wire, and it's rated for indoor use, you can run it to your current panel or splice onto it

Not even sure it IS 4-wire. 20 years old. I need to verify.

 

[mike93lx]

Not even sure it IS 4-wire. 20 years old. I need to verify.

If it isn't , you have to add a neutral or replace it.

 

[Joemctag]

Just to explain: It’d be great if I had an electrician I trusted to figure all this out. I’ll be doing the buried MHF and mounting disconnect myself, at a minimum. Just want to confirm what any electrician I hire might be saying.

 

[mike93lx]

Just to explain: It’d be great if I had an electrician I trusted to figure all this out. I’ll be doing the buried MHF and mounting disconnect myself, at a minimum. Just want to confirm what any electrician I hire might be saying.

We can help you through it, just need details. Wire type, pics of the inside of the panel in the trailer and the one that is feeding this. Stuff like that.

Is this site also in NC? If so, you are on 2020 NEC

State Electrical Code and Interpretations | OSFM

Information related to the State Electrical Code and Interpretations in North Carolina

www.ncosfm.gov

 

[Joemctag]

We can help you through it, just need details. Wire type, pics of the inside of the panel in the trailer and the one that is feeding this. Stuff like that.

Is this site also in NC? If so, you are on 2020 NEC

State Electrical Code and Interpretations | OSFM

Information related to the State Electrical Code and Interpretations in North Carolina

www.ncosfm.gov

I’m going to get pics, it it’ll be tonight or tomorrow. Thanks for your help.

 

[Norcal]

I’m looking at the NEC “4-wire to DETCHED building” schematic.
So, my m.h.’s panel would now be a sub panel?
Says disconnect means required at nearest entry point.
A suitable disconnect mounted to a 4x4 p.t. post just outside the outer wall of the m.h.?
And try to be prominent so it could be found in an emergency?

A trailer panel has always been treated like a subpanel, a enclosed breaker & grounding electrodes will to be provided at the back of the trailer, a simple junction box will not cut it. Another solution is either upgrade the existing 200A, service to 400A, or if the PoCo is agreeable set a pole with a 200A service by the trailer & connect it there.

 

[Mzungu]

A trailer panel has always been treated like a subpanel, a enclosed breaker & grounding electrodes will to be provided at the back of the trailer, a simple junction box will not cut it. Another solution is either upgrade the existing 200A, service to 400A, or if the PoCo is agreeable set a pole with a 200A service by the trailer & connect it there.

Maybe when it's in a trailer park with a rented pad, but on private land its common to see them with the meter mounted on the side just like any other house.

 

[wyliesdiesels]

If it isn't , you have to add an EGC/ground or replace it.

fixed it for ya

 

[wyliesdiesels]

A trailer panel has always been treated like a subpanel, a enclosed breaker & grounding electrodes will to be provided at the back of the trailer, a simple junction box will not cut it. Another solution is either upgrade the existing 200A, service to 400A, or if the PoCo is agreeable set a pole with a 200A service by the trailer & connect it there.

ive seen some that were not set up like that

 

[mike93lx]

fixed it for ya

I assumed the third was bare for some dumb reason

 

[Joemctag]

Got pics but will have to learn how to post.
The MH panel is a Cutler-Hammer. Four ********* wires and a somewhat smaller green coming in. My questions so far are:
Will I need a disconnect ? Just outside the MH where my feed is coming up ? Can I go to an electrical supply and they’ll give me the right one. Code says something about stickers ( for identification in an emergency).
Code says I need ground rod(s) at MH. What’s the easiest way to do this. Sand for a couple feet, then clay.
Also, the building I want to feed from has a meter on the exterior but not a disconnect there.
I guess the first, biggest question is whether I can feed a 200A MH panel ( will become a sub panel) from a 200A panel in the building.
What if I put a gas furnace or fireplace insert to eliminate the present electric furnace, thereby not needing anywhere near 200A?
Would that entail getting a lesser-amperage panel?

 

[wyliesdiesels]

Got pics but will have to learn how to post.
The MH panel is a Cutler-Hammer. Four ********* wires and a somewhat smaller green coming in. My questions so far are:
Will I need a disconnect ? Just outside the MH where my feed is coming up ? Can I go to an electrical supply and they’ll give me the right one. Code says something about stickers ( for identification in an emergency).
Code says I need ground rod(s) at MH. What’s the easiest way to do this. Sand for a couple feet, then clay.
Also, the building I want to feed from has a meter on the exterior but not a disconnect there.
I guess the first, biggest question is whether I can feed a 200A MH panel ( will become a sub panel) from a 200A panel in the building.
What if I put a gas furnace or fireplace insert to eliminate the present electric furnace, thereby not needing anywhere near 200A?
Would that entail getting a lesser-amperage panel?

are you sure its 4 and not 3? should only be 3 plus the green ground.

As to connecting to connecting to the building with the meter, is there a breaker panel on the inside?

 

[Norcal]

Pictures would be helpful.

 

[wyliesdiesels]

Pictures would be helpful.

 

[mike93lx]

are you sure its 4 and not 3? should only be 3 plus the green ground.

As to connecting to connecting to the building with the meter, is there a breaker panel on the inside?

I'm guessing the green was going to the ground rods

 

[wyliesdiesels]

I'm guessing the green was going to the ground rods

but the EGC should not be the same size as the other conductors

 

[mike93lx]

but the EGC should not be the same size as the other conductors

Usually isn't, but could be. He could also be mis gauging it. To someone that isn't in the know, a #4 could look similar enough to a #2 that they don't notice it at a glance

 

[Joemctag]

are you sure its 4 and not 3? should only be 3 plus the green ground.

As to connecting to connecting to the building with the meter, is there a breaker panel on the inside?

My mistake. 3 *********= two hits and neutral and a green to ground bar.

 

[Joemctag]

I'm guessing the green was going to the ground rods

Yes. Breaker panel almost immediately inside.

 

[mike93lx]

Breaker panel almost immediately inside.

Not sure what this means

 

[sparky 1971]

There's probably a bare #4 going down that used to go to the rods, or it goes to a ground bar mounted to the frame with an additional hole or another lug that went to the rods. Or, it could just be cut off and hanging there.

 

[u2slow]

IMHO, the practical thing to do is put the largest breaker in the metal building's 200A panel that it allows - likely 100-125A - and feed that to the mobile.

It is doubtful this would fly with a permit unless you crippled the mobile's electric heating (and whatever else) to arrive at a load calc that would fly on the 100-125A breaker.

While it's more work, you may be able to redo the metal building's service gear to allow 150-175A thru to the mobile. I doubt you will be able to get the full 200A though, because the metal building will need a base amount (its own load calc.) This is also contingent the metal building has a full 200A in the first place.

 

[wyliesdiesels]

IMHO, the practical thing to do is put the largest breaker in the metal building's 200A panel that it allows - likely 100-125A - and feed that to the mobile.

It is doubtful this would fly with a permit unless you crippled the mobile's electric heating (and whatever else) to arrive at a load calc that would fly on the 100-125A breaker.

While it's more work, you may be able to redo the metal building's service gear to allow 150-175A thru to the mobile. I doubt you will be able to get the full 200A though, because the metal building will need a base amount (its own load calc.) This is also contingent the metal building has a full 200A in the first place.

There is no code that would prohibit breakering the MH feeder at 200a

 

[u2slow]

There is no code that would prohibit breakering the MH feeder at 200a

Ya, I can't speak for NEC directly.... I know i had to reel it in on a previous job because the AHJ cited the shop demand took away from what could carry on to the house. Ymmv.

 

[Joemctag]

Ya, I can't speak for NEC directly.... I know i had to reel it in on a previous job because the AHJ cited the shop demand took away from what could carry on to the house. Ymmv.

Thanks, you all! I now have the professional opinions of some electricians who work to the NEC every day, so I’ve got a pretty good picture of where things stand and what all the options are.