Wire size challenge - 200A service

[DELDEL]

Hello,

I've got a detached shop that I'm trying to get wired up. Here's what I know so far:

House has 400A total and was pre-wired with a 200A service to feed the shop (see photo)

I've got a 2" (Inside Diameter measurement) conduit running between the house and the shop.

I've measured the string and I'm going to need 90' of wire to connect the house panel to the shop panel.

The shop has a ground lug already installed in the foundation.

I've bought the breaker panel and all the boxes, wire, etc. for the shop so once I get the feeder wire in there I'm ready to get started.

I've got a permit and I plan to have an Electrician help me with the actual connecting of all the wires.

Can I get some help with a recommendation on the wires I need to run between the house and the shop? Please understand I've got very little knowledge in this arena. Based on what I see in the picture I'm looking at running 2 large insulated wires (probably aluminum wire I assume?) Do I also need to run a ground wire?

Thanks much!

 

[DELDEL]

I'm located in Oregon (near Portland). I have a Home Depot near my house as well as a Platt Electric supply and other options.

Just looking for a recommendation (manufacturer, size, etc) on the feeder wires.

I'm also concerned that 2" ID is going to be tough (too small) to pull the wire through. Any advice is appreciated. I've read a lot of info on here, clearly there's some smarts here!

Thanks much!

 

[MrMark]

You need 4 wires. Two phase wires (hots) and neutral and a ground.

I don't have my ampacity table handy but as I recall you need 3/0 copper or 250kcmil aluminum for 200 amps with 75 degree rated terminations.

For 3 3/0 copper and one #4 ground you need 2 inch conduit sch 40 PVC for under 40 percent fill ratio. So you should be OK there.

That bare aluminum wire in your picture is your neutral.

If that is a separate 200 amp service to feed your shop (just located at the house) and it feeds only the shop you can use smaller feeder wires under the special table in the NEC for feeders that supply 100 percent of the load. This table lets you use an undersized feeder wire . You will have to look at that table for specifics but it allows you to use 1 or 2 sizes smaller wire if you qualify.

Of course, you don't need to run a full 200 amp feeder to your shop as this seems like total overkill unless you have some very special requirements. It's tough for me to imagine how 100 amps wouldn't be more than adequate.

 

[Aceman]

What I'd pull, all aluminum USE RHH, etc:

2- 4/0
1- 2/0
1- #4

As long as your calculated load is less than 180 amps it is legal to put 4/0 AL on a 200 amp breaker. If you need the full 200 amp wire capacity, then you'll need 250 MCM AL or 3/0 Copper.

I will tell you 4/0 is a bear to drag into 2" pvc. It fits and it's legal, but it's not fun. You will be wore out depending on how you pull it. We've done it quite a bit for mobile homes, etc. I think most of us in the shop are to the point now where we'd rather run 2.5" if we have any 4/0 to pull in.

Without looking it up I'm not sure if 250 MCM is even legal in 2", so if you want that 200 amp capacity you may have to use 3/0 copper $$ instead, or replace the pipe.

 

[Backlight]

Take a look at the Southwire site - http://www.southwire.com/ProductCatalog/voltdroprevised.jsp

It has a calculator that will help you understand what is needed depending on your input criteria.

 

[DELDEL]

Thanks very much for the replies. Good info and now I have some idea what to do.

When I bought all the other supplies I did purchase some 90 pound string (small rope) and a bottle of the wire pulling soap. The conduit only has two 90 degree bends in it so hopefully that will help.

I'll start pricing the wire and go from there.

 

[FordsnFishin]

Code calls for 4/0 aluminum to feed a 200 amp service. Assuming its a 120/240 panel you will need 2- size 4/0 wires for your hot wires, 1- 4/0 wire for your neutral and a #4 ground.

Pulling it will be a bit of a bear im sure. Look up on how to make a good wire head. (strip ends of insulation and stagger the head to make the end smaller) Use a good thin rope to pull it in, and look into maybe getting a small bottle of pulling lube.

 

[kiatech]

Pulling that in 2inch is possible. Make sure to use lots of lube and have lots of rags.

 

[Mustang51js]

Since you have the two inch pipe you need to pull 3 2awg copper wires and a #4 thhn stranded ground. You can't go to aluminum because the pipe would be to small and tough to pull through. You don't have any other option
2awg is rated for 195 amps but your allowed to bump it up for 200 amp service.

 

[MrMark]

He said 200 amps not 100 amps.

 

[wyliesdiesels]

Since you have the two inch pipe you need to pull 3 2awg copper wires and a #4 thhn stranded ground. You can't go to aluminum because the pipe would be to small and tough to pull through. You don't have any other option
2awg is rated for 195 amps but your allowed to bump it up for 200 amp service.

What r u talking about? #2 CU is rated at 115a.....Did u mean 2/0 CU? Thats rated for 175a NOT 195a because the 90* c column is for derating purposes ONLY!

 

[Mustang51js]

Yes I meant 2/0 and it's what we use in nj for 200 amp services,never had an issue

 

[Mustang51js]

And technically if it's under ground pipe it's suppose to be 2 1/2 pipe for 200 amp service, but again it's what we have to do in nj

 

[alfredeneuman]

2/0 copper, (or 4/0 aluminum) is good for 200 Amps...... if it's a service, or feeder that feeds the whole building load.

Read NEC Table 310.15(B)(7)

The OP has a 400 amp service, and 200 amps are dedicated to the shop.
So it isn't a service, and doesn't need 2-1/2" conduit to meet the POCO's requirements.

 

[Norcal]

What I'd pull, all aluminum USE RHH, etc:

2- 4/0
1- 2/0
1- #4

As long as your calculated load is less than 180 amps it is legal to put 4/0 AL on a 200 amp breaker. If you need the full 200 amp wire capacity, then you'll need 250 MCM AL or 3/0 Copper.

I will tell you 4/0 is a bear to drag into 2" pvc. It fits and it's legal, but it's not fun. You will be wore out depending on how you pull it. We've done it quite a bit for mobile homes, etc. I think most of us in the shop are to the point now where we'd rather run 2.5" if we have any 4/0 to pull in.

Without looking it up I'm not sure if 250 MCM is even legal in 2", so if you want that 200 amp capacity you may have to use 3/0 copper $$ instead, or replace the pipe.

2/0 copper, (or 4/0 aluminum) is good for 200 Amps...... if it's a service, or feeder that feeds the whole building load.Read NEC Table 310.15(B)(7)

The OP has a 400 amp service, and 200 amps are dedicated to the shop.
So it isn't a service, and doesn't need 2-1/2" conduit to meet the POCO's requirements.

Residential service though, a shop is not a residence, otherwise as was said above if the load is 180A or less, & doubt it would be that hard to stay under that.

 

[wyliesdiesels]

Yes I meant 2/0 and it's what we use in nj for 200 amp services,never had an issue

And youre talking main service entrance wire, ie. from the service drop to the meter pan, while the OP is talking branch feeder. So no it wouldnt be to code to use 2/0 for a 200a branch feeder.

 

[Champanada]

I would go to your nearest electric supply dealer and ask for SE cable and tell them what size panel you are feeding (200A) and they will do you right if they are worth their salt (but ALWAYS back it up with what is in the NEC manual). SE cable will be MUCH easier to handle and pull through the 2" conduit (may be a little more $$ but DEFINITELY worth it!).

 

[pattenp]

I believe since the OP's shop is detached the conduit is buried, so SE cable is not allowed.

I would go to your nearest electric supply dealer and ask for SE cable and tell them what size panel you are feeding (200A) and they will do you right if they are worth their salt (but ALWAYS back it up with what is in the NEC manual). SE cable will be MUCH easier to handle and pull through the 2" conduit (may be a little more $$ but DEFINITELY worth it!).

 

[alfredeneuman]

When I bought all the other supplies I did purchase some 90 pound string (small rope) and a bottle of the wire pulling soap. The conduit only has two 90 degree bends in it so hopefully that will help.

Do NOT use 90lb test pull string to pull the wire.
Besides risking it breaking, 9 out of 10 times it will saw into the inside radius of the PVC elbow because of diameter of the string and get stuck.

Get the biggest diameter pull rope you're able to get hold of and pull it through with the string.