Sub Panel Dilemma for addition over garage

[kamlung]

currently have a 30A subpanel wired in a attached garage with #10 wire. we are building ~700 sq ft of finished living space above the garage attached to the existing structure.

i am going to need about 6 circuits for the 2nd floor (1 for new 2nd zone HVAC unit going in the attic, new outlets and lights... instead of running 6 new lines from the main panel in the basement, the GC suggested running 1 line to a subpanel for the 2nd floor... my problem is that i don't want it to be an eyesore seeing a panel in the hallway...

my options:

1.) run a new #6 wire to the subpanel for a 60A breaker and abandon the old wire. (it's buried in the concrete slab so it won't be easy to replace)...

2.) keep the existing subpanel for the garage and put a new subpanel in the second floor hallway... (i'd like ideas on how to make it less of an eyesore)...

3.) instead of 6 lines, run 3 lines for new outlets and the HVAC... i'll tie the second floor lights into the existing sub panel since 30a is more than enough for what i do in the garage... i have gas heat and don't weld so it's just outlets and lights...

i figure #2 is the best way to future proof myself but i am trying to keep everything nice looking, especially for the Mrs.

 

[AntonLargiader]

If it's easy enough to run new cable to the garage sub, that would keep things tidy. It's kind of a pain to have a specific area of the house fed from two different locations IMO.

 

[tyme2par4]

I would go either 1 or 3. I don't see any reason to have a second sub panel, if you already have one just 1 floor down. Plus, as you mentioned, it's difficult to make them look good.

But if you're upgrading the garage sub panel, you might as well go up to 90A. If you use aluminum SER or MHF, it'll probably be the same price or cheaper than 6AWG copper.
90A gives you plenty of room to expand for HVAC, maybe even in the garage if you ever want to. Plus if you ever consider getting a EV or Plug-in vehicle, you'll want to be able to run a 40-50A circuit for charging.

 

[kamlung]

what size AL wire would i need to handle 90A? i've never worked with AL before, i'm assuming it's much better than before...

 

[Fordman7795]

what size AL wire would i need to handle 90A? i've never worked with AL before, i'm assuming it's much better than before...

2-2-2-4 mhf

 

[tyme2par4]

2-2-2-4 mhf

or SER if indoors.
MHF must be run in conduit inside. SER has a protective jacket like NM, so conduit isn't required, but it cannot be run underground.

 

[AntonLargiader]

Also of course the panel has to be rated for at least 90A. But panels are cheap. $50-ish gets you a 100A Homeline panel with a few breakers.

 

[kamlung]

what are you guys thoughts on pulling 3 wire to run a multi circuit? is it ok to share a neutral if i wanted to branch the lights for the two bedrooms off a single run... i'm trying to limit the homeruns and keep the box tidy so i figured one 14-3 to the attic and then branch a 14-2 to each bedroom...

 

[AntonLargiader]

As long as you realize that they will act as one circuit, fine. If one trips, both trip. If you have to shut one off for work, you lose the other as well. That's because they need to be on a double breaker or handle-tied pair.

 

[kamlung]

hmm maybe i'll look for 4 wire with ground? i saw it before but seems to be rare??? not something i can get easily at HD/Lowes...

 

[kamlung]

Also of course the panel has to be rated for at least 90A. But panels are cheap. $50-ish gets you a 100A Homeline panel with a few breakers.

so something like this...

http://www.homedepot.com/p/Eaton-12...ck-Includes-5-Breakers-BR1224L125V1/100557051

 

[AntonLargiader]

I prefer having a main breaker in every panel, but it's not required, so yes that would work.

I recently updated and moved a subpanel and used this:
https://www.lowes.com/pd/Square-D-4...-Main-Breaker-Load-Center-Value-Pack/50311143

 

[kamlung]

^^^thanks... the reason i went with that is because my house is currently Eaton and my OCD was trying to keep the brands consistent... even though one would be CH type and the other BR type...

so if i do a main breaker in the subpanel, i can do a 90a or 100a main breaker in the subpanel as long as i have a 90a breaker at the main panel it should be fine??? or should i also have a 90a main breaker in the sub panel as well...

 

[AntonLargiader]

The panel will probably come configured as a 100 or 125. That's fine, since it is not acting as the OCPD but rather just as a switch. All that matters is the 90 that feeds it from your main panel.

 

[slimpickins]

Make sure your main panel has the capacity as well. Hopefully your inspector won't come along and tell you you have to upgrade your main panel and service wires!

 

[kamlung]

i am thinking that my main is ok...

it is a 200a, 42 slot panel... it should be good to go... i don't have heavy draw items on it...

 

[kamlung]

got the wire from Lowes... started drilling out the joists with a 1 3/4" bit... hopefully i'll get the wire run by this weekend...

i'll post an update once done... thanks again all..

 

[wyliesdiesels]

got the wire from Lowes... started drilling out the joists with a 1 3/4" bit... hopefully i'll get the wire run by this weekend...

i'll post an update once done... thanks again all..

What wire did u go with for the feeder?

 

[kamlung]

AL 2-2-2-4 SER as per the recommendation on here... much lighter and easier to bend...

of course a snafu... drilling out the 1 3/4" holes in the joists, my 4 yr old harbor freight drill finally died after about 8 joists... so i went to Lowes to pick up a Dewalt hammer drill on sale... it couldn't even get through 1 joist before it locked up, i backed it out and pulled the trigger with no load on it, the motor snap, crackled, popped, a puff of smoke started bellowing out and it caught on fire... WTF... i guess back to the cheapo throwaway drills at harbor freight...

 

[AntonLargiader]

That's what I'd expect with a dull hole saw, but I can get through our 90 year old oak joists with a regular drill if the hole saw is sharp. Then again, I'm not drilling 1-3/4" holes. Isn't that a bit big for 2-2-2-4 SER?

 

[kamlung]

is it a bit big but i'm going to be pulling 40ft of it through a span of 20 joists, so i figure to make my life a bit easier and oversize the hole rather than have to fight it...

i'll check the bit again but it's one of those self feeding lenox bits... my plumber let me borrow it since my cheapo hole saw was taking forever...

 

[tyme2par4]

is it a bit big but i'm going to be pulling 40ft of it through a span of 20 joists, so i figure to make my life a bit easier and oversize the hole rather than have to fight it...

i'll check the bit again but it's one of those self feeding lenox bits... my plumber let me borrow it since my cheapo hole saw was taking forever...

the self feeding bits require a lot of torque. That's what those big right angle drills are for. They have much higher gear reduction for less speed, more torque. I have some screw tipped spade bits, and my cordless drill won't work unless I'm on low speed.

 

[wyliesdiesels]

AL 2-2-2-4 SER as per the recommendation on here... much lighter and easier to bend...

of course a snafu... drilling out the 1 3/4" holes in the joists, my 4 yr old harbor freight drill finally died after about 8 joists... so i went to Lowes to pick up a Dewalt hammer drill on sale... it couldn't even get through 1 joist before it locked up, i backed it out and pulled the trigger with no load on it, the motor snap, crackled, popped, a puff of smoke started bellowing out and it caught on fire... WTF... i guess back to the cheapo throwaway drills at harbor freight...

what kind of bit were u using? An auger? Was this a cordless drill?

Drilling studs and joists requires a drill with gear reduction that has a lot of torque, such as a hole hawg, as said above.

 

[kamlung]

the self feeding bits require a lot of torque. That's what those big right angle drills are for. They have much higher gear reduction for less speed, more torque. I have some screw tipped spade bits, and my cordless drill won't work unless I'm on low speed.

what kind of bit were u using? An auger? Was this a cordless drill?

Drilling studs and joists requires a drill with gear reduction that has a lot of torque, such as a hole hawg, as said above.

thanks both... yea it was a self feeding monster bit on a corded drill... even though the dewalt was variable speed, i couldn't get it slow enough to make the cuts... i ended up returning the dewalt and going to harbor freight for a cheapo $25 drill.. surprisingly the cheapo got the rest of the holes done... i snaked half the wire on the first floor and just need to pull the rest to the basement.. should finish tonight...

 

[TractorJeff]

Did they change the CODE where if you ran 14-3 as PO suggested that it would have to tied on a double breaker, not two separate breakers serving 2 rooms?

 

[Ohmthis]

^^^^
Go back and read post #9.
OP, why are planning two speedster circuits for lights in two rooms? What kinda lights are you planning on? One circuit will easily cover the lighting (general lighting) needs for whole space. 15a at 80% is 1440 watts. That is 14 100 watt bulbs, but with today's LED and CFL bulbs thats 100 of the 13w (about 60w equivalent) bulbs.

 

[kamlung]

^^^^
Go back and read post #9.
OP, why are planning two speedster circuits for lights in two rooms? What kinda lights are you planning on? One circuit will easily cover the lighting (general lighting) needs for whole space. 15a at 80% is 1440 watts. That is 14 100 watt bulbs, but with today's LED and CFL bulbs thats 100 of the 13w (about 60w equivalent) bulbs.

originally i was going to run it up to a junction box and split the lighting for the bedrooms and bathroom... i'm going to be running a heat lamp/fan in the bath and was afraid of the draw... but then the bedroom light circuit would only have two ceiling fans on it... i also checked the heat lamp and it's a dual bulb system and not the 4 bulb system so doesn't need a fully dedicated 15a...

you are right, with the LEDs in the lights and all the fans i could run the two bedrooms and bath (even with the heat lamps and fan) on a single 15A... i'll also have a 20a line for the GFCI that i'll tap the load side for the shower lights so i'll have lots of wiggle room...

 

[Ohmthis]

originally i was going to run it up to a junction box and split the lighting for the bedrooms and bathroom... i'm going to be running a heat lamp/fan in the bath and was afraid of the draw... but then the bedroom light circuit would only have two ceiling fans on it... i also checked the heat lamp and it's a dual bulb system and not the 4 bulb system so doesn't need a fully dedicated 15a...

you are right, with the LEDs in the lights and all the fans i could run the two bedrooms and bath (even with the heat lamps and fan) on a single 15A... i'll also have a 20a line for the GFCI that i'll tap the load side for the shower lights so i'll have lots of wiggle room...

 

[kamlung]

thanks all for your help... i passed rough inspection on the electrical today... he said everything looked tidy... even asked if i did this for a living... so i guess i take that as a complement...

funny thing was the first box he looked in, i forgot to tie up the ground... but i said really, the first one you look at i forgot??? everything else looked good...

he also made a comment to make sure for final everything has arc fault on it... didn't know about this code... (i guess i'm a bit outdated)... so for the bedrooms lighting and outlets i'll get the breaker and the mudroom... do i also need it for the garage? i'm assuming no...