I'm in the planning stages of my house build.  The shop building is up and I need to install the meter and the generator transfer switch.  Here's a MSPaint of my planned electrical supply plan.  

I do not yet know what kind of wire the electrical company will install.  I have talked to them about this but the only info they have given me is that depending on the distance to the pole, they may run high voltage lines underground, then install a power transformer on the ground near the shop building.  I haven't shown this to them yet but will next week and want to be armed with more info before talking to them.

The power will run to the shop building and the meter and generator transfer switch will be next to each other.  The power will then tap off for a 100 amp box in the shop and then 200 amp service to the house.  This house really could run on 100 amps (propane will be a main heat source for those appliances that need it) but I want to have the extra capacity for the event that it's needed....and 200 amps is standard for new construction anyway.  I have a 100 amp box in the shop but it will never use that much.  The biggest consumers in the shop will be the air compressor (30 amp circuit) and the stick welder (50 amp circuit).  

All the power lines will be underground in conduit.

Comments??

Thanks in advance!!!

I could be wrong but I don't think that will pass the national electric code as I think there is some code about not being able to feed one build though another. That said the power company can and will do what ever they want. You on the other hand are at the mercy of your local building inspector and must go by what he say's.

After reading my out of date code book(1990) I found the code I was thinking of 230-3 titled One building or other structure Not to Be Supplied Through Another does not apply to you as long as your service does not pass though the interior of another building. How ever according to code section 230-84 you will need a disconnect on both your house and one for your shop.

1) L1, L2, and N are all the same gauge.  split phase power for the win!

2) does the layout of the buildings on the lot mandate that the power come to the shop first?  unless there are extenuating circumstances, i would bring the POCO service drop to the house, put the meter there, put the 200A panel there, and then run a feeder to the 100A panel at the shop.    if you try another approach (namely to the non-residence building first) i worry that the POCO or building inspector may insist that you have two service drops and two meters –– this is going to cost you extra up front and monthly as well.  note that you will need a pair of ground rods at both panel locations, since they are separate structures.

3) the whole-house transfer switch is a good idea and maps in better if the POCO service drop is at the house first.  otherwise, you are going to have a complicated situation, both from an installation and code perspective.  where is the generator in relation to the shop and house?  this thread needs moar MSPaint!  

ar-jedi

Why not a 400 amp service, meter base is not that much bigger. Feed shop straight out the back of the meter can. Then you feed the transfer switch, transfer switch into 200 ampere disconnect. Disconnect to feed house panel. Pulling meter kills all utility power to property. Killing disconnect removes all power to house.
If generator is close to meter the generators built in breaker can kill emergency power.

Wait forgot emergency power to shop.

Thinking that having 200/200 in both places would be nice for future use.

Transfer switch is a disconnect that will kill both buildings, and the panels in the shop and home should have main breakers which kill each panel.

uh I see a problem with you line drawing, You can't feed you shop off the 200 amp transfer switch without using a fusible disconnect and you'll have to feed the disconnect with wire rated for 200 amps and then fuse it down to 100 amps. The fuses are to protect the wire not the items being fed.


of course the simple solution is to buy a 200 amp meterbase/ panel combo. The combo has a 200 amp main breaker with feed through lugs off the bottom side of the busbars and the you install a 100 amp breaker in the combo panel and feed the shop with #2 copper 2 hots, neutral and a ground. making sure that the shop panels neutral bar is not bonded to ground (no green screw through neutral bar into the panel Can)

Wire the house the same way but use 3/0 copper 2 hots, neutral and a ground.

One thing that has changed is that each sub-panel needs its own ground rod (the shop and the houses panels are sub-panels) The meterbase/panel combo is the main panel and only requires 2 hots and a neutral from the power company your 2 ground rods provide the required grounding and they have to be bonded to the incoming neutral to "balance" any unbalanced loads.


you'd probably be better off doing what I said above and just feeding the house with the genny and not the shop.

I hope that isn't confusing,
Jason

Good info.  Thanks.

For starters, there are no codes where this will be built.  Therefore, there will be no inspections.  I want it to be right and safe but no one will be there to check it.  The power company will check the meter loop and if it's to their standard, that's all they care about.  

My current house, built in 2008, is wired this exact same way except the main power lines enter the shop building, go to the transfer switch, and then run into the house.  There are code inspections there but the code inspector was fine with it.  Only issue that he had was to make sure that the power lines running through the shop building were encased in conduit.  

I want to be able to provide power to the shop building in case of a power outage.  That's not an option.  

I plan to run the generator near the transfer switch.  

I will probably upgrade the wire to 4/0, 4/0, 4/0, 2/0.  Most builders around here from what I have seen use either 4/0, 4/0, 2/0 (3 wire) or they use 4/0, 4/0, 2/0, 2/0 (4 wire).  I have read that the 4/0, 4/0, 2/0, 2/0 is fine for 200 amp service but the cost difference is minimal I imagine and I suspect I can buy it locally or within a 30 mile drive.  

My current house is fed with 200 amp service and uses 4/0, 4/0, 2/0 wire.  

The need for a fusible link on the shop electrical supply is a good comment and I'll check into that.  

Where do you live that there are no code inspections

Here's what I would do Put a 400 amp meter can on shop and feed the transfer switch then on the output side of the switch replace the single cable lugs with doubles lugs. Then run one wire from the double lugs to the shop panel and the other wire to the house being sure to provide overcurrent protection that the poster above suggested. You can then feed the other side of the transfer switch from the generator and both the house and shop will have back up power

I don't know why people find it so hard to believe that there are no code inspections in some places.  I live in MO and many counties in MO have no codes and therefore, no inspections.  

The only thing that is inspected is the septic system.  The county health department inspects it.  Only real restriction on it is that you have to have a perc test and it can't be closer than 100 feet from any well.  The health dept inspection takes about 15 mins.

Basically that's what I plan to do except that I'll have 200 amp service instead of 400.  I have no need for 400 amp service.

The reason I suggested a 400 amp sevice is that in your drawing you show a 200 amp panel in the house and a 100 amp panel in you shop for a total of 300 amp. If that is the way you are going you cannot use a 200 amp meter can and since they don't make a 300 amp meter can you must use a 400 unit. Now if you only put a 100 amp panel in the house a 200 amp service will work but building a new house and only installing a 100 amp service is like putting the engine from a 1950s  corvete in a 2011 corvete. I see this type of mistake all the time where people think they can get by with the smallest size because that is all they need at the time and then later on wish the had gotten the bigger one.

Ground rods are for lightning and pole transformer leakage.
They do nothing at 120 V.





Fusible links are not used for residential wiring.

The overcurrent device being fed protects the line from overload, while the POCO protects everything before the first overcurrent device from a short with a line fuse on the high side of the pole transformer.

This is one of the reasons for the very high interrupting requirements of circuit breakers.
The actual amount of current available until the breaker opens is VERY large.
10,000 amps is a low value.

The 100 amp box inside the shop is protected by a 100 amp breaker for the entire box and then each circuit has breaker protection.  The entire circuit is protected with a 200 amp breaker at the meter...before the transfer switch.  So, does there need to be any further protection?

I have 200 amp service now in my house and have never needed more....and this is in an all electric house.  

When I build the house where this electrical diagram is going, we'll have mostly propane appliances and propane heat.  I'm going to need less electrical service in the new place than I have now...and the house now draws a LOT more electrical power than the new house will require.  

Since there is a 200 amp breaker at the meter, the max it will allow into the shop and the house together is 200 amps.  I do not need or want more than 200 amps.  

As far as the location of the meter is concerned, locating it on the shop building will be the best in this situation.

I have checked with several people and everyone so far has told me that it's fine to install a 200 amp box in the house and a 100 amp box on the shop because the entire circuit is protected with a 200 amp breaker.....so I can't draw 300 amps even if I tried.  

I don't even NEED 100 amps to the shop building.  That's oversized but the 100 amp box offered me the number of breaker slots that I needed for the 240 and the 120 circuits.

Sounds fine.

Even in places with no county codes there is almost always a state mandated code that must be followed.

Inspections may not occur, but you still have to meet the state required code.

You would not believe some of the building methods that builders get away with in the rural areas where I live.  The cities pretty much have adopted various building codes but many of the rural areas have not.  And seriously, anything goes!!  However, as you can imagine, electrical fires are quite common in the area that I live in!!  

I want to build this house properly and educating myself on the proper methods is the best way to hold any contractor's feet to the fire to ensure that it's done correctly.

For example, 2 ground rods are NEVER installed in this area.  From my reading though, if you use one ground rod you MIGHT have enough grounding but should test it....and the average person and contractor does not have the required equipment to test it.  However, 2 ground rods are almost always (I would say always but then someone would argue that point too!) enough without any measurements.  More grounding cannot be a bad thing and it doesn't add much cost to the final bill.

ok, simple solution that does not require any more protectective devices isto replace the 100 amp panel in the shop with a small 200 amp panel(20/40 space) and upsize the original feed from the transfer switch to the shop panel to 4/0, 4/0, 4/0 no ground required (transfer switch is a disconnect not a panel)  remove the single lugs and replace with double lugs as suggested above on the load side of the transfer switch.

Jason

So telling me that the grounds are for lightening and transformer leakage sounds like a lot of manure!

The resistance of the earth is way to high to conduct significant current at 120 V.

Ever heard of the ‘worm getter’?
It was a pair of metal rods connected to a wall plug.
You pushed the rods into soil, and then plug it into a 120 V receptacle.

The current between the rods drives worms to the surface.
After unplugging the rods you gather the worms.  This is what got the product banned by CPSC since folks forgot to unplug the thing and got shocked when they touched the earth.
At no time would even 15 amps flow to turn off a breaker.
Even grounding rods are only required to be less than 25 ohms to earth.
That means a current as small as 4.8 amps at 120 V is all that would flow.

At 7,200 volts the current through 25 ohms would be 288 amps.

Pole transformers have capacitive leakage from the primary to secondary side.
The earth ground at a service entrance is to make sure the neutral (grounded) conductor from the pole transformer cannot charge up from the high voltage leakage.

It also provides a ready ground path for lighting surges that may be conducted on the lines.

“no that does not sound fine, Without over current protection from the meter base(at 100 amps) to the 100 amp panel ( assuming is fed with 100 amp wire) the Wiring feeding the panel will burst into flames and destroy his shop in the event that there is a significant enough short but not enough to trip the 200amp breaker at the meter base.”

Wiring from meter bases to panels is not normally protected under the NEC.
The POCO provides short circuit protection, while the panel prevents the line from being overloaded.
Any short is going to be way over 200 amps, especially if the conductors are rated to carry 100 amps.