Main Electrical Hookup to New Cabin

[TexasK5]

Getting ready to connect the main electrical to a cabin that was just built that is next to an existing structure that already has power.

Originally, when the barn was built, running that line was part of the deal with the builder. What I didn't do was make sure that the line he was planning to run was large enough for future plans that we knew included a cabin. After the line was in, I found out it was 1/0 aluminum. This is "adequate" for the barn, but not enough to continue on to the new cabin.

For the cabin, the underground run will be ~250 feet, and then up to the panel on the pole and into the cabin.

Currently there is a feed through panel at the pole and the 1/0 is connected at the feed through lugs. I am planning to install a 125A double pole breaker, move the 1/0 barn feed to the new breaker and connect the cabin feed to the feed through lugs.

Based on voltage drop and the expected loads (standard cabin stuff, all electric, no gas), I believe that 4/0 aluminum will be enough for that distance. Of course, 3/0 copper would work as well, but is considerably more expensive.

Looking for advice on the most cost effective way to do this. I see some 4/0-4/0-4/0 aluminum wire available that indicates that it is suitable for direct burial. Is this a good idea? Would I just have conduit where it exits the ground at the pole and cabin and everything in between is in the ground, no conduit?

I haven't seen any 3/0 copper suitable for direct burial, so that means 250' of conduit as well. Then it looks like the conduit needs to be glued together first and then pull the cable. Seems like pulling that may be beyond a diy task. Is there an easier way to do this that I am missing?

A sketch is attached to show the layout.

Any help is appreciated.
Thanks

 

[mike93lx]

Holy ****, that's a lot of power for a "cabin". My last house was all electric except the boiler and it had 60a service for 50+ years.

Might be worth looking at heat pumps for hot water and climate control

 

[ford33]

My entire house only has 100 amp service. What does a cabin need with 125 amps?

You are going to spend a lot of money for service you may not need.

 

[TexasK5]

I was really just planning on:
2 mini split A/C units
Stove/Oven
microwave
TV/Stereo
Small Water Heater
Misc. (Lights, etc)

Maybe Cabin is the wrong term. At some point, this will probably be our permanent residence.

 

[wyliesdiesels]

Youre putting the cart before the horse.

Have you done a load calc?

Also, is this gonna be fed off the current structures power?

If so, you need 4-wire feeder not 3-wire along with 2 ground rods and an isolated neutral in the subpanel.

I suggest reading the applicable comments on the electrical FAQ sticky...

 

[TexasK5]

The new connection will not be going through the existing structure. It will be 3 wire from the pole to the cabin. New ground rod at the cabin.

I am only planning to do this once, which is why it will either be 3/0 copper or 4/0 aluminum. I have already made up my mind about this. What I am wondering is the most cost effective way to do this.

Thanks

 

[wyliesdiesels]

Where is the meter going?

 

[TexasK5]

meter is on the pole

 

[wyliesdiesels]

meter is on the pole

And no disconnect with it?

Do you really want that much unfused wire on the property?

 

[TexasK5]

The meter feeds a 200A outdoor rated feedthrough panel that is also on the pole.

 

[wyliesdiesels]

The meter feeds a 200A outdoor rated feedthrough panel that is also on the pole.

Are the feed through lugs protected by the 200a main?

 

[TexasK5]

Yes -

 

[wyliesdiesels]

Yes -

Then you must run 4-wire feeder with isolated neutral in the subpanel.

The 200a main is your first means of disconnect.

 

[Bert_]

My entire house only has 100 amp service. What does a cabin need with 125 amps?

You are going to spend a lot of money for service you may not need.

Agree, OP will never pull more than 50-60 amps with the loads listed, probably much less. 100A leaves plenty of room for future growth.

But if you insist,

Nobody runs copper for feeders like this, aluminum is 1/4 the cost. As mentioned you need 4 wires. My preference would be 4/0-4/0-2/0 with a #4 ground.

Get some triple rated URD if you go direct bury or individual XHHW conductors if you run conduit the whole way. You are correct that pulling wire like that will require some equipment. Could probably rig some stuff to diy but direct bury is so much easier.

 

[jim111]

Mobile home feeder is your best choice. Price it at wireandcableyourway.com

 

[mike93lx]

Then you must run 4-wire feeder with isolated neutral in the subpanel.

The 200a main is your first means of disconnect.

This is exactly why the OP shouldn't be making final decisions on things like this based on a gut feeling or desire.

Would have sucked to pull a 3 wire feed the whole way then find out it was wrong.

 

[TexasK5]

Agree, OP will never pull more than 50-60 amps with the loads listed, probably much less. 100A leaves plenty of room for future growth.

But if you insist,

Nobody runs copper for feeders like this, aluminum is 1/4 the cost. As mentioned you need 4 wires. My preference would be 4/0-4/0-2/0 with a #4 ground.

Get some triple rated URD if you go direct bury or individual XHHW conductors if you run conduit the whole way. You are correct that pulling wire like that will require some equipment. Could probably rig some stuff to diy but direct bury is so much easier.

Perfect. Thanks.

 

[TexasK5]

Mobile home feeder is your best choice. Price it at wireandcableyourway.com

Thank You

 

[strutaeng]

Hey, contact Elliot Electric Supply. I went to the one in Carrollton and saved money when I bought some Al. wire for detached garage subpanel installation. They seem to have one in West Ft. Worth.

 

[TexasK5]

Hey, contact Elliot Electric Supply. I went to the one in Carrollton and saved money when I bought some Al. wire for detached garage subpanel installation. They seem to have one in West Ft. Worth.

Great. Thanks. I am planning to be in that area tomorrow (West Fort Worth) and will stop by and see what they can do.

 

[TexasK5]

Hey, contact Elliot Electric Supply. I went to the one in Carrollton and saved money when I bought some Al. wire for detached garage subpanel installation. They seem to have one in West Ft. Worth.

Thanks for the tip on Elliot's. About the same price/ft. as wireandcableyourway.com, but without the $130 shipping charge.

 

[wyliesdiesels]

Theres a diagram on this thread that will show you how and why a 4-wire feeder is needed.

https://www.garagejournal.com/forum/showthread.php?t=356460

 

[strutaeng]

Cool on the saving shipping costs. So what cable did you get, MHF?

Are you doing the work yourself?

 

[TexasK5]

Cool on the saving shipping costs. So what cable did you get, MHF?

Are you doing the work yourself?

Yes, and yes. Just need to rent a trencher.

 

[strutaeng]

Cool. There are members here that are pro electricians and have a wealth of information. The diagram that wyliesdiesels posted is like the bible of wiring subpanels.

As far a trenching, rent a big machine (like a 36"). I rented one in the Spring to replace a portion of my sewer and took advantage of trenching for my detached garage subpanel. My soil is really rocky and having a heavy machine helps from keeping it from bouncing around. The large units are also self-propelled.

I recently talked to a co-worker that told me he rented a small trencher for doing a trench at his deer lease and told me it was too much work because the machine just kept bouncing around. He said he wished he would have rented a bigger machine. Just a thought.

Maybe a ride on is better since you have to trench a lot.