how many wires are needed

[Youngfd]

I am running power from my house to small cabin out back. Feeding from house with a Square D 30 amp 2pole breaker to cabin 100 amp Square D box. 80 foot run underground in conduit. Using10 gauge stranded THHN wire. Do I need to run 3 or 4 wires to feed it?

 

[Stuart in MN]

Four wires: two hots, a neutral and a ground.

 

[zmaxmotorsports]

How big of a breaker are you feeding it off of in the house,how big is the conduit?
Youll need 4 wires for the sub panel.

 

[CNGsaves]

What's out in the "cabin" for power loads ??

You've got 100A panel out in cabin . . . . WHY ??

Why not just run MHF Al 2-2-2-4 and be prepared for ANYthing in future ?? At about $1.50/ft it's cheap and easy solution ran in conduit end-to-end.

 

[theoldwizard1]

10AWG is pretty sketchy for that distance @30A. 8awg THWN would be much better.

MHF can be direct buried (although of the experts here will tell you not to). MHF MUST be run inside conduit inside any building.

 

[Youngfd]

I have two 200 amp panels in house. 100 amp panel in cabin is over kill. Cabin is 10 by 12 feet. One breaker for outlets. One breaker for lights. One breaker for small wall heater.

 

[zmaxmotorsports]

I have two 200 amp panels in house. 100 amp panel in cabin is over kill. Cabin is 10 by 12 feet. One breaker for outlets. One breaker for lights. One breaker for small wall heater.

The 100a rating of the panel isnt a big deal,its only going to get what breaker feeding it will allow.
If youre using a plain old 100a sub without a main in it Id install a 2p breaker in it to use as a main disconnect ,just make sure to screw it to the panel or get a kit to clamp it down.

 

[Stuart in MN]

10AWG is pretty sketchy for that distance @30A. 8awg THWN would be much better.

It's only about 2.5% at 80 feet, if he draws a full 30 amps. Shouldn't be a problem.

 

[CNGsaves]

I have two 200 amp panels in house. 100 amp panel in cabin is over kill. Cabin is 10 by 12 feet. One breaker for outlets. One breaker for lights. One breaker for small wall heater.

Ah ha, then "cabin" really IS a cabin. Some people call a 30'x40' two story log cabin (really a full size house) . . just a cabin !!

Any future plans to put in water heater out there ?? A tankless would be nice to have and you could put freeze-proof hot/cold spigot outside and have warm water to wash cars nearby year round !! 240v tankless HWH would be just the ticket for unlimited hot water.

For the trouble of trenching out the 80 ft to cabin, still might be good idea to "Overkill" the wire and make it future ready.

 

[wyliesdiesels]

10AWG is pretty sketchy for that distance @30A. 8awg THWN would be much better.

MHF can be direct buried (although of the experts here will tell you not to). MHF MUST be run inside conduit inside any building.

Naw. He will be fine. At max load it will be less than 6v drop.

The 100a rating of the panel isnt a big deal,its only going to get what breaker feeding it will allow.
If youre using a plain old 100a sub without a main in it Id install a 2p breaker in it to use as a main disconnect ,just make sure to screw it to the panel or get a kit to clamp it down.

The only breaker hold down kit that can be used is the one listed for the panel. A plain old screw won't do. But i think u already know this being an EC.

Ah ha, then "cabin" really IS a cabin. Some people call a 30'x40' two story log cabin (really a full size house) . . just a cabin !!

Any future plans to put in water heater out there ?? A tankless would be nice to have and you could put freeze-proof hot/cold spigot outside and have warm water to wash cars nearby year round !! 240v tankless HWH would be just the ticket for unlimited hot water.

For the trouble of trenching out the 80 ft to cabin, still might be good idea to "Overkill" the wire and make it future ready.

An electric tankless WH uses a TON of electricity. Some even require a service upgrade.

A 13KW requires over 50a. An 19kw and 24KW require 75a and 100a respectively. If hes gonna do an electric tankless hes gonna need wire thats a lot larger than #10.

 

[Youngfd]

Thanks for all the info. The original 3/4" conduit was used to run a 50 AMP breaker to our hot tub. I checked the wiring that I pulled out of that last night and it was larger than 10 ga. I see that the green ground was one size smaller than the 3 main feed wires. A 8 ga. upgrade would make sense and still easy to do at this time. I have attached a few pic of our guest cabin. Named the "NO TELL MOTEL"

 

[woodzy]

That would make a great "dog house" for the times you are in trouble the better half..

 

[zmaxmotorsports]

Naw. He will be fine. At max load it will be less than 6v drop.



The only hold kit that can be used is the one listed for the panel. A plain old screw won't do. But i think u already know this being an EC.



An electric tankless WH uses a TON of electricity. Some even require a service upgrade.

A 13KW requires over 50a. An 19kw and 24KW require 75a and 100a respectively. If hes gonna do an electric tankless hes gonna need wire thats a lot larger than #10.

You can run a long skinny machine screw between the breakers and thread it into the panel if you know what youre doing with it,done it many times over the years with many differant inspectors without a problem.

 

[Youngfd]

I took the advice and went with 8 gauge wire instead of the 10.

 

[LS6 Tommy]

Mind if I ask how much your taxes went up for the No Tell Motel?

Tommy

 

[theoldwizard1]

Mind if I ask how much your taxes went up for the No Tell Motel?y

My brother-in-law built a couple of these on his vacation property. No tax impact because they are "non-permanent" buildings, built in skids. His have no electricity, heat or plumbing. They use battery lights or oil lamps and portable heaters. Communal outhouse. They have a "community" building with a kitchen, table and chairs.

 

[zmaxmotorsports]

Heres a picture of a 2p breaker attached with a screw like I was talking about,It was on a job I looked at yesterday in lincoln.
I wouldve taken a picture of the rest of the panel but it was such a disgusting install someone else did that it made me want to hurle.
Come to think of it all of the plumbing and wiring done in the house made me want to lose my lunch,I told him he needed to call a demolition contractor instead of an electrician and ran like hell!

 

[404]

Thanks for all the info. The original 3/4" conduit was used to run a 50 AMP breaker to our hot tub. I checked the wiring that I pulled out of that last night and it was larger than 10 ga. I see that the green ground was one size smaller than the 3 main feed wires. A 8 ga. upgrade would make sense and still easy to do at this time. I have attached a few pic of our guest cabin. Named the "NO TELL MOTEL"

A very nice looking cabin. Well done.

 

[wyliesdiesels]

Heres a picture of a 2p breaker attached with a screw like I was talking about,It was on a job I looked at yesterday in lincoln.
I wouldve taken a picture of the rest of the panel but it was such a disgusting install someone else did that it made me want to hurle.
Come to think of it all of the plumbing and wiring done in the house made me want to lose my lunch,I told him he needed to call a demolition contractor instead of an electrician and ran like hell!

The pic is a little blurry but is that K+T in the lower left of the pic?