Please Review My Project and Service Calcs

[CCWest1]

Guys,
I need your help in reviewing my project and especially my service calculations. I am attaching 7 files to give you a broad view of what I'm trying to accomplish. Graphics are sometimes better than words. I have a piece of property where I will be putting 2 manufactured/mobile homes and a detached garage. Also a generator which will be for 1 home and the garage. I want to bring in two residential 200A services. My POCO is NYSEG, and I've been following their Spec Book. A bit uncertain if they will allow me to put in two services, though from what I have determined I think they'll allow it. We'll see. If there is anything you see here that needs to be changed please let me know. I am kind of scratching my head on the calcs, so let me know. Thanks!

 

[roger]

CCWest1, please update your profile to include your occupation.

 

[Fred B]

Site plan is such that you only have one service with two feeders for the mobile homes/barn. Contact your AHJ or EI as all this would be approved or denied by them.
Size service from POCO pole to Meter pedestal would need to be appropriate for entire site. POCO (NYSEG) would not normally provide 2 separate services onto the site.
Service pedestal would normally get a service trough and taps into each meter base and each would also have a disconnect at the pedestal.
If wire size is a concern for costs, you can run parallels, but additional considerations need to be made such as same idea of the trough and taps to the individual meters. Also if parallel installation is done the Grounded (neutral) conductor would be sized in each set of parallel as if it was the only Grounded (neutral) conductor for the to entire loads. In this case if the calculations are correct and Size for the parallel can be 4/0 your neutral would need to be a Minimum 3/0 not the normal expected minimum of a #2. (This rough calculation, to really calculate the neutral size you would use the Circular Mils of the ungrounded conductors and the chart in 250.102(C)(1). )

Review of 230.2 and 230.3 would be appropriate in this installation. (Current code cycle NYS outside of NYC is the 2017 NEC)

 

[CCWest1]

Site plan is such that you only have one service with two feeders for the mobile homes/barn. Contact your AHJ or EI as all this would be approved or denied by them.
Size service from POCO pole to Meter pedestal would need to be appropriate for entire site. POCO (NYSEG) would not normally provide 2 separate services onto the site.
Service pedestal would normally get a service trough and taps into each meter base and each would also have a disconnect at the pedestal.
If wire size is a concern for costs, you can run parallels, but additional considerations need to be made such as same idea of the trough and taps to the individual meters. Also if parallel installation is done the Grounded (neutral) conductor would be sized in each set of parallel as if it was the only Grounded (neutral) conductor for the to entire loads. In this case if the calculations are correct and Size for the parallel can be 4/0 your neutral would need to be a Minimum 3/0 not the normal expected minimum of a #2. (This rough calculation, to really calculate the neutral size you would use the Circular Mils of the ungrounded conductors and the chart in 250.102(C)(1). )

Review of 230.2 and 230.3 would be appropriate in this installation. (Current code cycle NYS outside of NYC is the 2017 NEC)

Thank you Fred! Great reply. and very informative. Looks like I'm back to the drawing board. Have a nice day!

 

[CCWest1]

CCWest1, please update your profile to include your occupation.

Done. Thank you.

 

[roger]

Done. Thank you.

It didn't work, let me know what it should be and I will fix it for you.

 

[tortuga]

Nice layout two comments I have
You have 32 kVA of load on a Automatic transfer Switch (ATS) to a 24 kW generator.
Since its an optional standby if you look at article 702.4 you need to either manage the load with load shed,
provide a 32kVA or larger generator,
or disable the 'automatic' part of the transfer switch and wire it to manual transfer only (toggle switch start).

Many generator dealers sell these load shed devices to meet 702.4(B)(2)(b) (just an electrically held contactor), this could be complicated by the fact your mobile home is a 100A feeder off the generator panel.


My other comment is for a mobile home you use 550.18 for the service calculations, which does allow you to use the 220.82 optional but gives you a few other options there, usually with a new mobile home or mfg home its all provided for you, perhaps that is what you posted?

 

[CCWest1]

It didn't work, let me know what it should be and I will fix it for you.

Electrician, Semi-Retired

 

[CCWest1]

Nice layout two comments I have
You have 32 kVA of load on a Automatic transfer Switch (ATS) to a 24 kW generator.
Since its an optional standby if you look at article 702.4 you need to either manage the load with load shed,
provide a 32kVA or larger generator,
or disable the 'automatic' part of the transfer switch and wire it to manual transfer only (toggle switch start).

Many generator dealers sell these load shed devices to meet 702.4(B)(2)(b) (just an electrically held contactor), this could be complicated by the fact your mobile home is a 100A feeder off the generator panel.


My other comment is for a mobile home you use 550.18 for the service calculations, which does allow you to use the 220.82 optional but gives you a few other options there, usually with a new mobile home or mfg home its all provided for you, perhaps that is what you posted?

Hey, yeah...good catch but actually now a bummer....I reworked my calculations for the mobile #2 and the garage and I'm now coming up with 29248VA total. So going with a 30 or 32KW blows my budget out of the water. I would definitely prefer an auto TS, cause if I'm not around in the middle of winter things could freeze up on me. Thinking instead of going with a 100A auto TS that is not a SE switch, and just energizing essential circuits. The problem is essential circuits would be the mobile plus a couple of baseboards and well tank in the utility room of the garage. Hmmm...

And yes, the calculations for the nameplate loads were given to me by the manufacturer of the home.

 

[roger]

Electrician, Semi-Retired

Thank you

 

[tortuga]

Hey, yeah...good catch but actually now a bummer....I reworked my calculations for the mobile #2 and the garage and I'm now coming up with 29248VA total. So going with a 30 or 32KW blows my budget out of the water. I would definitely prefer an auto TS, cause if I'm not around in the middle of winter things could freeze up on me. Thinking instead of going with a 100A auto TS that is not a SE switch, and just energizing essential circuits. The problem is essential circuits would be the mobile plus a couple of baseboards and well tank in the utility room of the garage. Hmmm...

Since your going to have a open trench anyways and your a retired electrician I would just set a 2nd 'critical loads' panel in the garage, so the ATS is off a 100A feeder (not the service) then run a 2nd feeder from that panel to the mobile home and set a small second panel in there.
Then you probably could have a smaller generator.

 

[CCWest1]

Since your going to have a open trench anyways and your a retired electrician I would just set a 2nd 'critical loads' panel in the garage, so the ATS is off a 100A feeder (not the service) then run a 2nd feeder from that panel to the mobile home and set a small second panel in there.
Then you probably could have a smaller generator.

Thanks Tortuga! Sounds good!

 

[CCWest1]

Since your going to have a open trench anyways and your a retired electrician I would just set a 2nd 'critical loads' panel in the garage, so the ATS is off a 100A feeder (not the service) then run a 2nd feeder from that panel to the mobile home and set a small second panel in there.
Then you probably could have a smaller generator.

I reconfigured, did my calcs to come up with a smaller generator (18KW) with a 100A Auto Switch, and figured this out by adding a small additional panel in the mobile. I came up with total load of 14,175VA which takes care of the mobile circuits and circuits in the utility/garage. Only fly in the ointment is how to satisfy the code requiring a disconnect for the mobile within 30Ft. Meaning I would need a 4 pole switch, (2 poles for each panel) with a neutral bar, to disconnect the main mobile panel as well as the E-Panel which both originate and energized from inside the utility room. I'm seeing some 4 pole disconnects online ( some very expensive) but I can't tell if they come with a neutral bar, or if the manufacturer has one that can be added. The question is, if I was able to get the 4 pole 3R switch, would this be something that could even pass an inspection.

 

[tortuga]

Only fly in the ointment is how to satisfy the code requiring a disconnect for the mobile within 30Ft. Meaning I would need a 4 pole switch, (2 poles for each panel) with a neutral bar, to disconnect the main mobile panel as well as the E-Panel which both originate and energized from inside the utility room. I'm seeing some 4 pole disconnects online ( some very expensive) but I can't tell if they come with a neutral bar, or if the manufacturer has one that can be added. The question is, if I was able to get the 4 pole 3R switch, would this be something that could even pass an inspection.

Is it going to be classified as a 'mobile home' or 'manufactured home'? I think if its a manufactured home you would not need a single disconnect.
I think the difference is permanent foundation but I'd have to check the definitions in the code.
If you did want a 4-pole disconnect see who is a Siemens distributor in your area, as ITE / Siemens has 4-pole disconnects for 5-wire two phase they are sold in the PA market.

 

[CCWest1]

Is it going to be classified as a 'mobile home' or 'manufactured home'? I think if its a manufactured home you would not need a single disconnect.
I think the difference is permanent foundation but I'd have to check the definitions in the code.
If you did want a 4-pole disconnect see who is a Siemens distributor in your area, as ITE / Siemens has 4-pole disconnects for 5-wire two phase they are sold in the PA market.

According to NYSEG's spec book... Section X 2(c)... A mobile home with all running gear removed a securely mounted to a permanent foundation, can be considered a standard home for service entrance requirements (NEC Article 550 "Service Equipment" A & B), must also comply with NEC Article 230 "Services" & Article 250 "Grounding".

Here's the kicker...

The permanent foundation must be a poured concrete or block foundation with a cellar or crawl space, BUT NOT A SLAB ON GRADE WITH REMOVABLE SKIRTING. NYSEG will attach a service to a manufactured home which meets Article 550 if and only if the proper written evidence is provided that the NEC code is being met for permanent installation, service and grounding from the local authority(s) having jurisdiction.

Section X 2(d)... Mobile Homes Considered as Permanent Structures. The requirements of a permanent structure are an approved water supply and sewer system, and compliance with municipal zoning requirements. If not met, the service will be considered a temporary service. All work required for temporary service will be at the customer's expense.

In my case I do not meet the permanent foundation requirement, although my manufac./mobiles will be permanently connected to a water supply and sewer system. Even so, that only satisfies half of what they would consider as a permanent structure.

Thanks for the info on the disconnect. Do you think installing the Siemans 4 pole would pass the smell test? I suppose I could send my layouts to the local inspection agency before hand to get an answer. What do you think?

 

[tortuga]

According to NYSEG's spec book...

Since your meter is up the driveway and the service disconnect is the 200A panel in the garage you'd be running two feeders to the manufactured home.


I am not sure the utility has any say in how you run a feeder, at least they would not around here.

 

[CCWest1]

Please see the attached. From the way I am interpreting NYSEG's specs, the mobile disconnect must be in sight. If it's in my utility room, then the disconnect(s) are not within sight. In the diagrams from the spec book, NYSEG is showing the disconnects on a pedestal and it looks to me the intent is for them to be within sight.

 

[tortuga]

NYSEG is your electric utility right?
All they should be concerned with is your installing an electric service into a 2 garage that has a 200A service disconnect in the garage.
In my opinion the utility requirements end at the service point, which in your case is the service disconnect in the garage, after that its just the NEC.

 

[CCWest1]

NYSEG is your electric utility right?
All they should be concerned with is your installing an electric service into a 2 garage that has a 200A service disconnect in the garage.
In my opinion the utility requirements end at the service point, which in your case is the service disconnect in the garage, after that its just the NEC.

OK, interesting interpretation. I suppose you could look at their specs (diagram) as if you were just bringing service in solely for a mobile. But in this case the service to the garage basically changes that. I think what I will do, when I finally submit my application, is to show the garage without the exterior disconnect to the mobile, and see if that flies. Thanks!

 

[CCWest1]

OK, interesting interpretation. I suppose you could look at their specs (diagram) as if you were just bringing service in solely for a mobile. But in this case the service to the garage basically changes that. I think what I will do, when I finally submit my application, is to show the garage without the exterior disconnect to the mobile, and see if that flies. Thanks!

OK Tortuga, I'm playing with another option. I'm thinking seriously of scrapping the mobile and having a small modular put up within 10 feet or so of the garage. More costly but may be better for a number of reasons. The modular comes with a 200A main breaker panel. I'm still looking to bring the main service into the garage landing in a 200A 6 to 8 circuit main breaker panel with feed through lugs to the main panel in the modular. I used your idea of putting a small E-circuit panel in the modular. Please take a look at my sketch and let me know what you think. Thanks in advance!