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Updating electrical service in anticipation of adding shop building.

Updating electrical service in anticipation of adding shop building.

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  #1  
Old 03-06-12, 09:42 AM
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Updating electrical service in anticipation of adding shop building.

I'm am in the process of planning out the construction of a new pole barn style shop building and after consulting with the engineer from our Co-Op the electrical service running to the house will need some attention.

Currently we have 2 poles located on our property, one with the transformer and a second closer to the house with the meter and two disconnects. One disconnect was originally added when the service was installed and the second comes off a 60 amp breaker in the first and then runs to the garage that was added to the house at a later date. So its meter, main disconnect with 100 amp breaker and 60 amp breaker. 100 amp breaker is connected to the main panel in the basement via a buried cable that enters through the stem wall in metal conduit.

The cable from the second disconnect is also connected to the garage via a buried cable. To further complicate the situation the previous owners ran an overhead conductor from the meter pole back to the pole with the CT and then to a barn that is located adjacent to it. the engineer was not happy about that and wanted it to go away.

My plan is to construct a new building about 30-40 feet from the existing barn and have the meter base relocated to the pole where the transformer is now and upgraded along with the transformer to provide for the additional load of the new building. The current meter pole also containing the disconnects will be removed as part of this upgrade.

I would then like to trench and bury a new run from the new meter pole to the garage and mount a new service panel to act as the main and move the circuits presently on the 60 amp garage service and then run four copper conductor SER to the existing main panel int he basement and convert it to a sub-panel.

The exiting basement service is buried and under a rather wide concrete driveway slab and in order to get to the back o f the house where it enters the residence would require digging around several trees, a concrete slabbed dog pen and the well head so I would like to avoid it if possible.

In running the connection between the proposed new main panel in the garage and the existing main/new sub panel I would need to go up and through the attic or back outside and along the eaves in conduit then down and through the foundation. This is because the one half of the room adjacent to the garage used to be IN the old garage and the floor is solid concrete with no access underneath. Does traversing the attic cause an issues?

Does this seem like a valid plan?

Thanks in advance for your thoughts.
 

Last edited by Creaky63; 03-06-12 at 11:11 AM.
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  #2  
Old 03-06-12, 06:23 PM
Tolyn Ironhand's Avatar
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I see an issue here. You have a 60 amp feed to the garage and a 100 amp feed to the house. IF these structures are connected you have, in essence, one building. A building may only have one feed unless approved by the AHJ.

Your plan addresses this well by redoing the single feed to the garage and the new new SER to the house panel. You will have to replace the garage panel to one that is at least 100 amp. Of course, if you go larger than 100 amp, you will be required to up size the feeder wires.
Since the garage panel will be your service, you will also have to install a ground rod and run a water pipe ground to where your water comes into the house. You could run this that same time as you run your feeder. This will be sized by the size of your service wires. (250.66)

Running your wires should not cause any issues. Just make sure you say 6' away from any access hatches.

The the overhead wires going to the existing barn connected to anything? You only listed the 100 amp to the house and the 60 to the garage. Did the power company say why he want them removed?
 
  #3  
Old 03-07-12, 05:01 AM
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The 60 and the 100 both come out of a disconnect box mounted below the meter, i believe the 60 was added when the garage addition was done in the late 70s or early 80s. The garage is attached, interestingly the kitchen and both bathrooms were remodeled within the last 10 years and the work was done by a contractors. I would assume the needed permits would have been pulled and this and the existing wiring situation would have been inspected.

Of course that's an assumption I may have been allowed not sure. The plan was to place a 200 amp panel in the garage, take the circuits on the 60 and terminate them at breakers in the 200 and run to the existing 100 amp main in the basement with the SER converting it to a subpanel.

Will 2/0 copper suffice for the feeder? On the ground rod buried outside near the ingress to the new 200 in the gararage and tied to the 200 and a water pipe in the basement after running along with the feeders to the 100 in the basement?


I think the power company didn't like the idea of customer service wiring ran back and attached to the pole with the CT from the load street in case the had to climb it for some reason.

Thanks again.
 
  #4  
Old 03-07-12, 06:34 PM
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Will 2/0 copper suffice for the feeder? On the ground rod buried outside near the ingress to the new 200 in the gararage and tied to the 200 and a water pipe in the basement after running along with the feeders to the 100 in the basement?
2/0 copper, or 4/0 Aluminum, is correct for a 200 amp service. I like to use copper.

Many cases, unless something is very wrong with an installation, inspectors will let existing installations slide.
 
  #5  
Old 03-07-12, 07:11 PM
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So just to clarify between the new 200 amp panel in the garage and the existing soon to be sub panel it looks like I could use #2 copper is the 80% adjustment factor applies since there would need to be a 4 wire run to the new sub (2 hots, 1 neutral 1 ground). And the service drop from the meter base is 2/0 copper or 4/0 aluminum.

Thanks for your time and input again.
 
  #6  
Old 03-10-12, 10:47 AM
Tolyn Ironhand's Avatar
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The feed from the garage 200 amp panel, to the house sub panel can be:
#2 copper if it is non-metallic sheathed cable (romex)
#3 THHN if it is in pipe (PVC or EMT)
The ground may be smaller, #8 is fine.

You are correct on the service drop.
 
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