Sub panel 350 ft.

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  #1  
Old 07-30-09, 08:00 PM
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Sub panel 350 ft.

O.K. Pros want to be sure I have all my ducks in a row... for a safe project for myself and the next homeowner who may live here.

I have 200 AMP service in our home Homline Square D
I want to run a sub panel out to our shed,the total distance is 350 Feet.....Yes quite a long way..


Here are the tools with AMPS I have and will be using in our 12X 16 wood floor shed.

Table Saw .............18 Amp
Radial Arm Saw........12 Amp
Jointer...................15 AMP.
Planer....................16 Amp
8 Receptacles the first one being GFI protected this will be 20 amp circuit used for circular saw,electric drill,.. small power tools etc..
8 Pull chain lights on a 15 amp circuit

The same brand load center for sub as in home will be used Square D Homeline.

There will be an 18" deep trench with 2 inch schedule 40 PVC and a piece of rope for future wire pulls.

Now for my questions......

The first 100 feet is inside our home.Will I save any $$$ by using indoor wire before going outside with my LB the next 250 feet?

Will 2/2/2 and#4 ground be O.k.?

Must I run the copper ground all 350 feet?Thats a lot of copper...

One or Two ground rods at shed?

Can I put water lines next to PVC in same ditch?If legal ditch will be 24' deep for frost line.

Thank You to all the Pros for making this site possible..

God Bless....
 
  #2  
Old 07-30-09, 09:03 PM
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You need to do some thinking about how much power you're going to be using all at once. If you're the only one who's going to be out there, you may be able to get away with a two (MWBC) 20A circuits since I highly doubt you'll be using the planer, jointer, and saw at the same time. If two 20A circuits will be sufficient, you can do it with I believe 8/3 wire.

On the other hand, if you're looking to install an AC, electric heat, air compressor, etc... you'd probably want to look more in the range of a 60A service.


There will be an 18" deep trench with 2 inch schedule 40 PVC and a piece of rope for future wire pulls.
So far, so good. Though once you pull the 4 wires required, it may be difficult to pull more through because of the way the pull cord inevitably gets tangled around the wires. You may want to consider an extra 1" or 1.5" conduit for future telephone/intercom/network/etc.


The first 100 feet is inside our home.Will I save any $$$ by using indoor wire before going outside with my LB the next 250 feet?
Probably not much if you go the 60A or higher route. For that distance you'll probably want to run aluminum, and once you count the cost of the splices, large junction box, etc, you'll probably find it's close to a wash.

Will 2/2/2 and#4 ground be O.k.?
For a 60A service at 350', my calculations look like that's appropriate... but I'll defer to the pros on this one. Voltage drop is related to how much power is actually being pulled, not the maximum available. So if you only plan on using say 35A of the 60A service, you only have to account for 35A of voltage drop.

Must I run the copper ground all 350 feet?Thats a lot of copper...
Unless you're still under 2005 NEC AND don't plan any other metallic pathways to the building (no phone/network/copper water lines). Though an aluminum SER cable is probably a better bet in terms of cost.

One or Two ground rods at shed?
I believe it's 2, unless you can prove you have a good ground. Most people sink 2 rods because it's easier than testing and proving to the inspector that you have < 25ohms to ground.

Can I put water lines next to PVC in same ditch?If legal ditch will be 24' deep for frost line.
Yes. And I assume you mean 24". 24 feet is a long way to dig.
 
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Old 07-30-09, 09:16 PM
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SER cannot be used underground.
 
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Old 07-30-09, 09:25 PM
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Originally Posted by 63zerb View Post
There will be an 18" deep trench with 2 inch schedule 40 PVC and a piece of rope for future wire pulls.
According to "the book" you can get 7 #2 in a 1 1/2" pipe. 2" may be a bit over kill since the only thing I can see you adding is 3 or 4 #12 wires for a three way light(s).
I also agree with adding the empty pipe.
You may also may want to check into direct burial cable.

Originally Posted by 63zerb View Post
The first 100 feet is inside our home.Will I save any $$$ by using indoor wire before going outside with my LB the next 250 feet?
You will have to check on prices of 2-2-2 cable. I'm willing to bet it will be cheaper to just run pipe. I would use EMT inside though. Another consideration is how you are going to run the pipe/cable. Cable is much easier to bend and you can run it through joists to keep it out of the way. If you do choose to run cable I suggest getting a 6x6 or 8x8 plastic pull box instead of the LB.

Originally Posted by 63zerb View Post
Will 2/2/2 and#4 ground be O.k.?
A #8 ground is fine. #4 is oversized by two sizes. #2 @ 100 amps will give you a voltage drop of 5.5%. However you will never be pulling that kind of current unless everything is running at once which I'm guessing is unlikely. #2 should be fine.

Originally Posted by 63zerb View Post
Must I run the copper ground all 350 feet?Thats a lot of copper...
Yes, but see above. You will save money by only running the required ground. You could also run aluminum #6 if your wish. I personally would stick with copper.


Originally Posted by 63zerb View Post
One or Two ground rods at shed?
Sounds like you will have water in the shed. Therefore you need one ground rod and then bond the water service.

Can I put water lines next to PVC in same ditch?If legal ditch will be 24' deep for frost line.
Yup. No problem there.
 

Last edited by Tolyn Ironhand; 07-30-09 at 09:29 PM. Reason: because I type slow.
  #5  
Old 07-31-09, 08:55 AM
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Originally Posted by 63zerb View Post
Can I put water lines next to PVC in same ditch?If legal ditch will be 24' deep for frost line.
Frost line is not 24" in PA - you'll be sure to freeze your water line at 24". Most local jurisdictions use their own determination for frost line depth (the ICC building codes leave it blank for that reason, I'm told). Most places in PA the frost line is 36", some use 42" or 48" - and remember, you should be below the frost line.

Also, remember that the 18" depth for your PVC conduit is not trench depth, but the amount of cover required on top (between the top-of-pipe and the top-of-grade), so your trench will need to be at least 22-24" to place the conduit in it and still have 18" of cover.
 
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Old 07-31-09, 09:51 AM
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Originally Posted by 63zerb View Post
tools...8 Pull chain lights on a 15 amp circuit
You could get by with a 20A multiwire circuit using #8 or #6 copper. No room for expansion, but cheaper. Otherwise a small panel would be a good option maybe 40A-60A.

The first 100 feet is inside our home.Will I save any $$$ by using indoor wire before going outside with my LB the next 250 feet?
Probably no money, but you may save some hassle by using a cable which can be bent into joist spaces, etc. Personally I would recommend pipe all the way.

Will 2/2/2 and#4 ground be O.k.?
If you mean aluminum that's good for about 40A, copper 60A.

Must I run the copper ground all 350 feet?Thats a lot of copper...
As long as you don't plan on putting a pool out there, the ground can be aluminum.

One or Two ground rods at shed?
Two.

Can I put water lines next to PVC in same ditch?If legal ditch will be 24' deep for frost line.
Depends on the jurisdiction, but my experience is no. Of course that could be because our frost line is 42" and most water lines are at least 5'-6' deep. You said lines. Do you plan on running hot and cold out there? If so, I'd recommend just running cold and install a small under-sink electric water heater instead.
 
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Old 07-31-09, 07:54 PM
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Frost line in PA.,100Amp for growth....

Thank You All for the feedback...

Yes I will be the only one working at one time.Some time there will be the radial arm and table saw running depending on project.

I like the extra 1.500 PVC empty with pull rope for future wires.

There will be only cold water.A small hot water heater maybe in the future.

Sorry for typo....ditch @ 24 inches not feet Thank You Williswires for the frost line education in PA.I will go deeper if I do put water in ditch.

Ironhand ....Thanks for reminding me to put a 12-3 line in ditch before closing...

Now for more Questions...........

I want 100 Amp instead of 60 I would rather spend a little more now than try and grow in the future.

100 Amp what size wire and ground?A pool maybe........ in the far future.I like to do things right the first time.

One thing I forgot to mention......the netural and ground will NOT be bonded in sub.

Two ground rods..@ shed will be there.Lots of hard I do mean hard clay dirt here Soak er down good with water before trying to pound in?

Thank You all again......

Good Day
 
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Old 07-31-09, 08:11 PM
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Originally Posted by 63zerb View Post
I want 100 Amp instead of 60 I would rather spend a little more now than try and grow in the future.

100 Amp what size wire and ground?A pool maybe........ in the far future.I like to do things right the first time.
Your #2 copper you posted before will be fine for 100 amps. You do not anything larger than #8 copper for your ground.

Originally Posted by 63zerb View Post
One thing I forgot to mention......the netural and ground will NOT be bonded in sub.
Good plan!

Originally Posted by 63zerb View Post
Two ground rods..@ shed will be there.Lots of hard I do mean hard clay dirt here Soak er down good with water before trying to pound in?
Never tried that but I bet that would work. 350' trenching through hard clay. Sounds like good times. I'd help but I'm busy that day....Sorry.
 
  #9  
Old 07-31-09, 10:58 PM
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One more tip -- instead of gluing 35 pieces of conduit, you might want to inquire about HDPE duct at the supply house. It's a continuous plastic electrical pipe on a roll that will save you a lot of hassle gluing all that PVC.
 
  #10  
Old 08-01-09, 05:08 AM
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HDPE duct pipe......

Thanks Ibpooks I will look in to this @ electrical supply store.

Let me clarify I am still a bit un sure of wire and ground size.

For 100 Amp @ 350 feet run underground burial 2/2/2 all aluminum or copper?

Same question for the ground to clarify...350 feet #8 or #4?
 
  #11  
Old 08-01-09, 10:14 AM
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It depends on how much power you actually want and if you want to follow voltage drop recommendations. The code does not require us to compensate for voltage drop on long lines, however it does recommend that VD not exceed 3% (or in some cases 5%). If you truly want 100A available within voltage drop recommendations, you will be spending a fortune in wire. See this table.

AWG / Copper wire drop % / aluminum wire drop %
#3 6.9% ----
#2 5.5% ----
#1 4.4% 6.3%
#1/0 3.5% 5.0%
#2/0 2.8% 4.0%
#3/0 ---- 3.1%
#4/0 ---- 2.5%
 
  #12  
Old 08-02-09, 06:37 AM
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Thank you ........

Thank You for all the tips.I am heading to the blue store for supplies and get some real juice up there.
 
 

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