Underground service to the shop

[formula388]

Hi all, after much discussion with many people and varying opinions from each person. I have decided to come here to ask the help of people who have possibly done this in real life.

I own a house on Long Island NY, my garage is 200' away from the service at my house. I have a 200amp service at the house.
I want to run a sub panel at the garage. I have not decided on the amp rating of the subpanel just yet. That I guess is dependant upon both what I need and what I can afford. I plan on using it as a light duty/ personal/ hobby use auto shop. I will have a 2 post lift. 120v air compressor and other various tools. I dont plan right now on ever having a welder, though it is not fully out of the question.
I have begun to dig the trench from the house to the garage. I am about halfway done. Going 20" deep so that I will have a minimum of 18" of ground coverage.

So far I have considered for the wire:
In my budget of $600:
6/3UF-B direct burial @$3/ft total $600
4 Runs of 6awg THWN in Conduit @0.69/ft total $550 plus cost of conduit

Not sure if I can afford:
Aluminum USE 2-2-2-4 in Conduit (Cannot find cost yet)

I cant afford right now:
4 runs of 4awg THWN in conduit @ $1.10/ft total $880 plus conduit

My question is, what should do you all suggest?
Thanks in advance,
Dennis

 

[Norcal]

Hi all, after much discussion with many people and varying opinions from each person. I have decided to come here to ask the help of people who have possibly done this in real life.

I own a house on Long Island NY, my garage is 200' away from the service at my house. I have a 200amp service at the house.
I want to run a sub panel at the garage. I have not decided on the amp rating of the subpanel just yet. That I guess is dependant upon both what I need and what I can afford. I plan on using it as a light duty/ personal/ hobby use auto shop. I will have a 2 post lift. 120v air compressor and other various tools. I dont plan right now on ever having a welder, though it is not fully out of the question.
I have begun to dig the trench from the house to the garage. I am about halfway done. Going 20" deep so that I will have a minimum of 18" of ground coverage.

So far I have considered for the wire:
In my budget of $600:
6/3UF-B direct burial @$3/ft total $600
4 Runs of 6awg THWN in Conduit @0.69/ft total $550 plus cost of conduit

Not sure if I can afford:
Aluminum USE 2-2-2-4 in Conduit (Cannot find cost yet)

I cant afford right now:
4 runs of 4awg THWN in conduit @ $1.10/ft total $880 plus conduit
My question is, what should do you all suggest?
Thanks in advance,
Dennis

The grounding conductor is not required to be the same size as the ungrounded (hot) & grounded (neutral) conductors, which will lower your costs.

 

[Aceman]

It's hard to beat the price of #2 mobile home feeder.

 

[formula388]

Thank you both for the reply.
I see now that running the #2MHF in aluminum would be my cheapest option. It is rated for direct burial but i wouldnt mind putting it in conduit anyway. Does anyone know what would be my allowed ampres at the subpanel 200ft away?

Also, if running thwn, and the ground does not have to be the same size, what size should it be for 6awg and 4awg?

Thanks

 

[pattenp]

The MHF can be direct buried but does need to be in conduit where above ground and inside the structure. Here at Lowes they have 2-2-2-4 MHF @ $1.47 ft and HD has 2-2-4-6 MHF @ 1.69 ft. I don't know why HD has the higher price on MHF with the smaller neutral and ground. Be sure as to what you get because some stores carry Quadruplex UD cable and it looks the same as MHF but can not but installed inside. UD cable just carries a USE-2 rating and is to be only installed outside of the structure. The MHF cable also carries the RHH and RHW-2 ratings along with the USE-2 rating which allows it to be installed inside.

Edit: You can over current protect the #2 MHF up to 90 amps, but at 200 feet continuous loads at 60 amps and up will start to get over 3% voltage drops. All said, I think you'd be fine with the #2 MHF if you're just a one man DIY shop.

The grounds are as follows...21Amps up to including 60Amps is #10Cu or #8Al, 61A up to including 100A is #8Cu or #6AL, 101A up to including 200A is #6Cu or #4Al

 

[formula388]

So it seems like the MHF 2-2-2-4 is my best option in both price and amp rating.
Is there any negative to it? Is there a better option?

 

[pattenp]

When you say better option, as to how? Price, No. Copper is a better choice but you will pay 3 to 4 times the $ for it. In the end I think because of the distance you can't beat the aluminum for a feeder. The down side of aluminum is if the insulation gets nicked where under ground the aluminum will fail over time whereas the copper may holdup indefinitely. It's best to put the MHF in conduit the whole way, but is not required.

So it seems like the MHF 2-2-2-4 is my best option in both price and amp rating.
Is there any negative to it? Is there a better option?

 

[underpressure02]

I just went through a similiar situation as you. I built a 40x40 garage and it was 285 feet away from the house. I was trying to decide if I wanted to run from the house out to the garage or have a new feed coming from the pole. I have 400amp service to the house. In my case it was only about $100 dollars more to run a new 200 amp service from the pole to the garage.

I wasn't sure if I was going to spend the extra money on running conduit to the pole while using direct burrial but I am glad I did. Because after it was all buried I ended up having to pull some new wire from the pole to my garage since my meter box wasn't the power companies "approved" box and they wouldn't hook up my power unless I removed the box I bought and bought their specific box.

I ran direct burial 4/0 2/0 alum wire with 3 inch conduit.