# Major Service Upgrade - Rural Property



## buhljohnson (Apr 12, 2021)

Hello all. I am new to the community but have utilized this site for a while but I am in need of some help...
My family recently moved to an old farm house in a rural community and ever since we moved in, we've been bringing things up to code, starting with the old knob and tube wiring. The house is finally, completely rewired and now we need to focus on the property. Our property is fed with a pole transformer (15KVA) and a *lot* of areal wire. From the transformer, the wire runs to a pole on the neighboring property (the property lines were re-drawn when we moved in) and then back to our property to another pole with our main service panel which has 4 x 200 amp breakers. From there, one wire runs to a pole at our well (one of the 200 amp breakers), another to yet another pole that jumps our driveway to our house (another 200 amp breaker), and the 3rd and 4th 200 amp breakers are not used. We recently built a detached garage (shop) and rehabbed an old original barn and need to power both structures. The new shop will have a small guest-house which will have an electric range, small tankless water heater, mini-split system, and electric wall heater for emergency heat. The new shop itself will have various power and lighting throughout. The old rehabbed barn will be used as a wood shop with all sorts of electric tools. 
Our house is all electric - we have a heat pump / coil for heat/cooling, electric range, electric water heater, electric clothes dryer, etc. I recognize the 15KVA transformer is potentially too small to run some combinations of things on our property but am told by our utility company that it cannot be upgraded unless it fails (challenge accepted). 
But I do need to run new cable to the shop and barn and this would be a good time to upgrade/bury the feeder and delete most of the poles. I have included a 2-page drawing of the current and proposed configuration. I have no idea what type of wire / gauge I will need from the transformer to the main service panel and what size conduit to bury. Also, there are two points the conduit will cross over a water line - I am not sure what code allows for in this situation. I also am not sure if I need a separate sub panel for the apartment in the shop or if one sub panel will do for the whole structure. Any advice would be hugely appreciated before I start making a mess of things. Thank you!


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## 99cents (Aug 20, 2012)

What is a Limited Energy Journeyman? I have never heard the term before. Does it mean low voltage (by definition, 50 to 1000 volts)?


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## buhljohnson (Apr 12, 2021)

99cents said:


> What is a Limited Energy Journeyman? I have never heard the term before. Does it mean low voltage (by definition, 50 to 1000 volts)?


in my state it is "Specialty Electrical" - it is for elevator, escalator, dumbwaiter, moving walk, and/or manufacturing/assembling equipment.


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## SWDweller (Dec 9, 2020)

Not knowing where you are these questions need the crystal ball, mine is still in the shop with parts on back order.

15kva is to small for what you have, 4-200 amp breakers.

I would start with load calculations for each load/building. Then you have an idea what could be combined or needs to be separate.

Arizona utilities will not let you have multiple meters at the same voltage. So you would be forced into single service out at the road. All of the underground conduit and wire would be on your dollar.
Personally I would like the service on my property to keep the idle hands away
My utility will go ~325 from pole to pole, minimum clearances enforced, note the garage. This is usually free. 

Your underground drawing is not complete so I pass on comments.


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## mofos be cray (Nov 14, 2016)

99cents said:


> What is a Limited Energy Journeyman? I have never heard the term before. Does it mean low voltage (by definition, 50 to 1000 volts)?


Maybe he's a lazy journeyman? But it sounds better as limited energy?


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## Southeast Power (Jan 18, 2009)

If you design this and install it, this will be your masterpiece.


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## hornetd (Oct 30, 2014)

> buhljohnson said: Hello all. I am new to the community but have utilized this site for a while but I am in need of some help...
> My family recently moved to an old farm house in a rural community and ever since we moved in, we've been bringing things up to code, starting with the old knob and tube wiring. The house is finally, completely rewired and now we need to focus on the property. Our property is fed with a pole transformer (15KVA) and a *lot* of areal wire. From the transformer, the wire runs to a pole on the neighboring property (the property lines were re-drawn when we moved in) and then back to our property to another pole with our main service panel which has 4 x 200 amp breakers. From there, one wire runs to a pole at our well (one of the 200 amp breakers), another to yet another pole that jumps our driveway to our house (another 200 amp breaker), and the 3rd and 4th 200 amp breakers are not used. We recently built a detached garage (shop) and rehabbed an old original barn and need to power both structures. The new shop will have a small guest-house which will have an electric range, small tankless water heater, mini-split system, and electric wall heater for emergency heat. The new shop itself will have various power and lighting throughout. The old rehabbed barn will be used as a wood shop with all sorts of electric tools.
> 
> Our house is all electric - we have a heat pump / coil for heat/cooling, electric range, electric water heater, electric clothes dryer, etc. I recognize the 15KVA transformer is potentially too small to run some combinations of things on our property but am told by our utility company that it cannot be upgraded unless it fails (challenge accepted).
> But I do need to run new cable to the shop and barn and this would be a good time to upgrade/bury the feeder and delete most of the poles. I have included a 2-page drawing of the current and proposed configuration. I have no idea what type of wire / gauge I will need from the transformer to the main service panel and what size conduit to bury. Also, there are two points the conduit will cross over a water line - I am not sure what code allows for in this situation. I also am not sure if I need a separate sub panel for the apartment in the shop or if one sub panel will do for the whole structure. Any advice would be hugely appreciated before I start making a mess of things. Thank you!


As to your drawing and description I would want the answers to several questions prior to commenting. 

Please provide the length of the cable runs in feet between the service equipment and the feeder supplied building disconnecting means at each structure.
Will the guest house actually be for your guests or is it a rental?
Is your "old rehabbed barn" the building labeled "Existing Storage Shed" on the proposed drawing?
Will you be using the new garage and shop buildings to park or work on vehicles? 
That will effect how you will insulate the floor if you do so.

Is the well head inside a Well House or is it the kind with the well casing a foot or so out of the ground with a pitless adapter used for the water line?
Will you be making any provision for an Optional Standby Generator or for a portable/mobile generator connection? 
Will the generator power just the house or will it power more than one building?
Will you want portable/mobile generator connections at more than one building?

How close is your property to the nearest fire station in road miles?
I will offer a couple of things that you will want to consider before the foundation is poured for the new "Detached Garage and Shop." 

Check the frost depth of your area. Unless you've been having water line freeze ups in the underground piping you will probably find that the depth of bury for water lines is much deeper than the 2 foot required by the electrical code for buried electrical cable
A Concrete Encased Electrode and a Ground Ring are the 2 best electrodes you can have at a building that is not served by an all metallic piping water utility. There are some water utilities that will not except any underground plastic piping in their system. That makes their entire piping network one very large underground water pipe electrode. The following steps will allow you to have both a Concrete Encased and Ground Ring electrodes at your new building.

Were there is Rebar in the concrete foundation you are required to use it as a Concrete Encased Electrode. 
Make sure that the concrete folks know that there is to be no electrically insulating material between the footers and the soil! *None, Zip, Nada*. 
If you are going to heat the work area you will want to insulate the floor but that does not mean that you insulate the footings. 

Make sure that the concrete contractor's workers tie all of the crossing points of the 1/2 inch or larger rebar that is used in the footer. 
See that the concrete contractor has the Rebar to which you will connect the Grounding Electrode Conductor (GEC) stubbed up through the sill plate at the location of the new Building's Disconnecting Means so that it will be inside the wall.

Consider installing a ground ring before you backfill the footer. 
#2 AWG bare copper or larger encircling the entire building at a depth of 30 inches or greater. 
The deeper the better so as to get down into the permanent water table but 30 inches of burial is all that the US NEC requires. That said you would certainly not want to put it less deep than the bottom of the footer as long as that is more than 30 inches below the surface once it is graded. Since you will have some sort of excavator there dig the trench around the building to at least the frost depth if that is deeper than 30 inches.
Best practice is that the wire used for the Ground Ring should start and end at the Building Disconnecting Means (BDM) with enough extra length to be bring both ends into the BDM enclosure and terminate them to the Equipment Grounding Conductor busbar. The NEC allows the Grounding Electrode Conductor which is the sole connection to a Ground Ring electrode to be #4 AWG but that means that you will need to use a connector that is listed for both wire sizes and as suitable for direct burial. Using a continuous #2 or larger conductor and bringing both ends up into the BDM enclosure avoids the need for a direct burial connection and it connects both ends of the Ground Ring to the Equipment Grounding busbar.




Don't rush to remove the overhead wiring poles prior to considering if any of them would be a good location for a yard light or lights. 
If you install yard lights please use the sodium vapor type because their yellowish light can be filtered out of telescopes used by astronomers. The mercury vapor lamps produce a bluish white light that cannot be filtered. If you use the led lights consider using the yellow ones which can also be filtered.



Consider locating the 600 ampere Service Equipment panel at the well's location on a stanchion or the outside wall of the well house. 
That will make all of the feeder cables shorter and allow you to reduce the Feeder Conductor sizes to each structure to a smaller and thus less expensive gauge because being shorter there will be less voltage drop to compensate for with a larger wire size.
That also places all of the Over Current Protective Device (OCPDs) for the feeders serving individual buildings at the well were they can serve as the emergency disconnect for each building. If the 2020 edition of the US National Electric Code has been adopted in your area before you pull the permit for the electrical work, external emergency disconnects will be required for each building. Check to see if your areas AHJ will except individual breakers located in the Service Equipment enclosure at the well's location as the emergency disconnects. Some who will not except breakers in a single enclosure will except individual enclosed switches which have been assembled into a Service consisting of up to 6 enclosed switches or into colocated feeder Over Current Protective Device (OCPDs). In your case you could have up to seven because the one for the water well is specifically excluded from the 6 throws of the hand rule. The disconnect for the water well is even permitted to be at a location which is separate from the other switches or breakers.

Be aware that the only wire sizes that can be sized under the residential service and feeder exception will be the feeder to the existing house from the Service Disconnecting Means and the feeder for the apartment from the feeder's Over Current Protective Device (OCPD) to the panel for for the apartment. For a 200 Ampere residential feeder you can use 4/0 wire but for any other 200 ampere load, such as the new garage and shop, you would have to use 250 MCM wire size. All of the other feeders and any service lateral conductors that you install must be sized in accordance with table 310.16 ampacities for the size material and insulation type that you use.
The minimum size of supply for any single dwelling is 100 Amperes so that will be the size for what you are calling an apartment uless for some reason that I am unable to anticipate the calculation results in a larger size.
Don't forget that the terminals in most electrical equipment are only listed for use at 75 degrees Celsius. That means that you must use the 75 degree Celsius column ampacity for the wire you will install.
The Electrical Utility that serves your area may not be willing to have a Service Lateral run as far as you want yours to run and perhaps not even to the well. If that is true in your case you are going to have to install a single Service Disconnecting Means closer to the road and run a feeder from there to your first feeder supplied panel or a grouping of fused switches that will serve as the Feeder Over Current Protective Devices (OCPDs) for all of the individual buildings. 
Check the Utility's service standard now to avoid being caught out later.

The following points are about making it possible for you to extinguish a fire before it can spread beyond the room of origin. If you have a fire station within 3 road miles of your home then this section will be of less use to you even though someone like me would take these precautions anyway. The reason that I bring them up now is that while you are excavating and pouring concrete for you new garage and workshop is the least expensive time to install the new water lines and pour the footers for a new well house.

If you don't have one already consider building a well house to hold your pressure tank/s. 
If you do build one insulate it to the absolute maximum practical degree.
Most of your pressurized water should be in your well house were it will be available for first aid fire fighting with the shortest pipe runs to the individual buildings. 
That does not stop you from having pressure tanks at the 2 dwellings if you want to provide extra capacity or reduce the cycling of the well pump.


Consider installing a frost proof yard hydrant in each pipeline to a building, 50 feet from were the pipeline reaches the structure, to supply full sized 3/4 inch garden hoses. 
The full sized 3/4 inch garden hoses placed on reels at each frost proof yard hydrant must be long enough to reach the furthest corner on every floor of the building/s which each pipeline serves. 
The 50 feet is to allow you to apply water from the outside of any building without having to work too close to endure the radiated heat. 

Consider installing underground water cutoff valves on the building side of each yard hydrant so that the building can be cutoff without cutting off the yard hydrant.

As a kind of off the wall closing thought I cannot think why you would want an electric emergency heater. A pellet stove, wood stove, or a through the wall vented propane heater would all be better choices. If your house has a fireplace consider a fireplace insert and an outdoor supply of combustion air as a great alternative heat source. If that is too pricey consider installing an airtight front and a heatilator grate in the fireplace. Combine that with an outdoor source of combustion air and it would still be a pretty good alternative source of heat. For the same reasons you will want to include some non electric heater in the apartments design. There again if you have the room a fireplace with a supply of outside combustion air and an insert or heatilator would be good choices. If you don't have the room of inclination to include a fireplace then the most convenient one to install and use is a through the wall vented gas heater. Those can be fueled from 2 portable 35 pound cylinders and an automatic changeover valve quite conveniently. You must forgive me. I'm on my city's disaster preparedness committee. I just cannot help it!

*Once again it is up to the rest of the participants in this thread to review what I have suggested as a second check against my having made a mistake. It is far better that I be embarrassed by having my error pointed out than that I accidentally mislead the Discussion Starter into danger!*

-- 
Tom Horne


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## hornetd (Oct 30, 2014)

SWDweller said:


> Not knowing where you are these questions need the crystal ball, mine is still in the shop with parts on back order.
> 
> 15kva is to small for what you have, 4-200 amp breakers.
> 
> ...


He's in Idaho so I doubt the Arizona stuff is of much use to him. 

Many electric utilities are happy to give you a second meter if their state regulatory agency allows them to charge for reading and collating the 2 readings into a single bill. At say $20 a month for the second meter that is 240 dollars a year for every additional meter that they have to read. With modern self reporting meters or drive by reading that is free money.

-- 
Tom Horne


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