Residential addition branches vs subpanel

[strutaeng]

Hi guys, I'm going to start rough electrical in my 2 level addition project. My main panel has plenty of spaces and is about 3 feet from the existing corner (outside) of the house. The addition comes out about 8 feet from the same corner.

I was going to run EMT from main panel to the wall and up the new attic at the second level with THHN dual rated and then a junction box and transition to NM-B. It is 2 bedrooms, a study room and large family room. Probably 4 circuits and exterior lights. Conduit may be about 16' to attic. Probably need 100' spool of each color: black, white and green.

Also, just realized also need 220V for new AC. AC type T.B.D.

Another option I just though about is just do a subpanel to the upstairs study room with XHHW-2 or Cu and then use NM-B from there.

I was going to run 1 1/2" EMT the conduit. Actually, already bought it.

I'm just starting my outlet/lighting layout, so still have some 1 week or 2 to decide.

Thanks for your input.

 

[sberry]

You started out big. Personally would see if I can do all with 3 circuits and a 240, get it all in a 3/4 pipe if I could. 1 1/2 is odd anyway and I try to use as common, standard as I can. I ain't above running 2 pipes if I have to. Take the big back and work with 3/4
If you used 2 pipes could put 4 circuits in one, run the AC in another one.

 

[sberry]

There is nothing wrong with another panel, the box store has short pcs of 6/3 nmb just for this.

 

[strutaeng]

Ok, thanks for your tips.

Now, my current main box is outside, and the lines will have to run about 3 feet before they enter the new wall, so that entire line needs to be "wet" rated.

I'm starting to think the subpanel may be better for any future additional circuits in the new portion of the build...Just extra cost of the new subpanel, and the expensive AFCIs!

 

[strutaeng]

EMT wet use question Re: Residential addition branches vs subpanel

Ok, I've decided to go with the subpanel option. I'm using 1 1/4" EMT with #4 Cu. with an 80A breaker.

I did a load calc. and was like 56A, without AC. AC is probably going to be a 2 ton mini-split, so I should be good.

I went and bought the EMT and was putting the fitting on the main panel and I couldn't tell if the home depot fitting are water-tight? Looks like there are "raintight" fittings, but not sold at my local home depot?

https://www.homedepot.com/p/Halex-1...PIPHorizontal2_rr-_-100542484-_-100549474-_-N

I'm going to try an electrical supplier. Just need a male adapter and coupling before it goes inside the structure.

 

[wyliesdiesels]

There is nothing wrong with another panel, the box store has short pcs of 6/3 nmb just for this.

Cant use NM-b on the exterior.