Educate me on sub panels?

[paperfist]

Please

I have a 2nd floor I'm remodeling. When done it will have:
Bedroom - flat screen
Office - computer and small server
Tiny living room - small electric fireplace, flat screen
Bathroom - Jacuzzi tub (no heater), Toe kick heater for floor
Furnace - Forced hot air - 15 AMPs

So I've talked to a few electricians. 1 wants me to run a sub panel the other wants me to bring up 4 circuits from the panel in the basement. I've already run 3" conduit between floors.

I like the sub panel idea because it's one large wire to run. Breakers are easily accessible, and just seems like a cleaner solution.

One thing I'm not really grasping though is say it's a 60 AMP panel. I already ran 12/2 wire (over kill I know) to all the lights (LED) and receptacles. So now I need 3- 20 AMP fuse breakers for the 3 separate rooms (bedroom, office, living room) well that's already 60 amps. But the LED lighting and computers/TV aren't going to draw anything near 60 amps. So how does that work?

 

[Red Squirrel]

Electricians might be able to chime in on specific details but I think it's mostly a preference thing and panel space thing. If you run a sub panel you won't use up as many slots in your main. You just need to put a 60 amp double pole breaker and run a 4 conductor cable (not sure of gauge, I know 8 gauge is for 40 amps so guessing you need like 6) and then at the panel you will now have more slots for various circuits that can be used for that room and general area.

Also the breakers don't need to add up to less than the rating, as long as wire gauge is ok. Ex: you can put a 100a panel off another 100a panel that has other 100a panels or other circuits hanging off it, it does not matter as long as breakers are sized properly. It is assumed that every circuit is not going to be loaded 100% all the time, and even if it was to happen the appropriate breaker would trip and not allow it.

I would stick to 15 amp for lighting though, because most light fixtures may not be rated for 20 amps, it's generally not an issue though, but nothing stops someone from screwing in one of those socket receptables and putting a 2000w heater on it or something. I'm not sure how code handles lighting in this respect though. You can still keep the 12/2 wiring, but put a 15 amp breaker.

 

[echo4747]

Please

I have a 2nd floor I'm remodeling. When done it will have:
Bedroom - flat screen
Office - computer and small server
Tiny living room - small electric fireplace, flat screen
Bathroom - Jacuzzi tub (no heater), Toe kick heater for floor
Furnace - Forced hot air - 15 AMPs

So I've talked to a few electricians. 1 wants me to run a sub panel the other wants me to bring up 4 circuits from the panel in the basement. I've already run 3" conduit between floors.

I like the sub panel idea because it's one large wire to run. Breakers are easily accessible, and just seems like a cleaner solution.

One thing I'm not really grasping though is say it's a 60 AMP panel. I already ran 12/2 wire (over kill I know) to all the lights (LED) and receptacles. So now I need 3- 20 AMP fuse breakers for the 3 separate rooms (bedroom, office, living room) well that's already 60 amps. But the LED lighting and computers/TV aren't going to draw anything near 60 amps. So how does that work?

You will have to run 6awg wires from your main panel to the subpanel (4 total conductors), use a double pole 60A breaker in your main panel, it wont matter if the sum of the breakers in your subpanel exceeds 60amps. If for some reason you draw more than 60amps in total at any given time the breaker feeding that panel will trip. you will also need to remove the bonding screw (usually colored green) which will separate the neutral and ground bus bars in your new sub panel.

 

[echo4747]

You can still keep the 12/2 wiring, but put a 15 amp breaker.

correct

 

[Greenman]

You will have to run 6awg wires from your main panel to the subpanel (4 total conductors), use a double pole 60A breaker in your main panel, it wont matter if the sum of the breakers in your subpanel exceeds 60amps. If for some reason you draw more than 60amps in total at any given time the breaker feeding that panel will trip. you will also need to remove the bonding screw (usually colored green) which will separate the neutral and ground bus bars in your new sub panel.

Picking nits. You meant 3 conductors and a ground.

 

[echo4747]

Picking nits. You meant 3 conductors and a ground.

yes .. the ground is a conductor too .. thats why I said 4 total conductors. Just want to add that if the wire route chosen from the main panel to subpanel is more than 75ft consider increasing the wire size to 4awg

 

[Greenman]

yes .. the ground is a conductor too .. thats why I said 4 total conductors. Just want to add that if the wire route chosen from the main panel to subpanel is more than 75ft consider increasing the wire size to 4awg

The ground isn't a conductor, it won't normally have current passing through it. That's why romex is called 14/2 or 12/2, it only has 2 conductors, even though there are 3 wires.

It is a nit picky point, but it makes a difference. If the OP goes down to the local electrical supply and asks for 50' of 6/4 he's going to end up with 4 conductors and a ground (or the clerk telling him there is no such thing), when he only needs 3 and a ground.

It's obvious that you know electrical, and reading this you're thing "duh", but a lot of folks here aren't going to be up to par on terminology, and it matters.

Almost forgot to mention, no matter what size wire he runs to his sub, the largest ground he'll need will be a #6.

 

[echo4747]

The ground isn't a conductor, it won't normally have current passing through it. That's why romex is called 14/2 or 12/2, it only has 2 conductors, even though there are 3 wires.

It is a nit picky point, but it makes a difference. If the OP goes down to the local electrical supply and asks for 50' of 6/4 he's going to end up with 4 conductors and a ground (or the clerk telling him there is no such thing), when he only needs 3 and a ground.

It's obvious that you know electrical, and reading this you're thing "duh", but a lot of folks here aren't going to be up to par on terminology, and it matters.

Almost forgot to mention, no matter what size wire he runs to his sub, the largest ground he'll need will be a #6.

You are correct in that he would ask for 6/3 feeder.. but 6/3 does (typically a black,red,white,bare wire) why I said 4 total conductors ( could/should have said wires) but as far as the word conductor it could also mean anything which passes electrons easily (low resistance) but yes we are both being nit picky.
yes.. no matter what you will not need anything heavier than #6 for the ground

 

[Subyman]

Personally, I like to have everything at one panel, even if it costs more to run things. Unless, of course, it is run to an outbuilding. Then I like to have the panel there for obvious reasons. If you have enough room at your main panel then just do the 4 branches. The cost will likely a wash by the time you factor in another panel and heavy gauge wire.

 

[stormkroe]

The ground isn't a conductor, it won't normally have current passing through it. That's why romex is called 14/2 or 12/2, it only has 2 conductors, even though there are 3 wires.

It is a nit picky point, but it makes a difference. If the OP goes down to the local electrical supply and asks for 50' of 6/4 he's going to end up with 4 conductors and a ground (or the clerk telling him there is no such thing), when he only needs 3 and a ground.

It's obvious that you know electrical, and reading this you're thing "duh", but a lot of folks here aren't going to be up to par on terminology, and it matters.

Almost forgot to mention, no matter what size wire he runs to his sub, the largest ground he'll need will be a #6.

Do you have an NEC ref for the #6 ground requirement? The reason I ask is, here in canadia, we are also allowed to ground with a #6 for up to a 2000 amp service, but anything past the ground connection to the neutral in the main panel (or first point of disconnect which would include a meter socket with breaker), is considered a 'bonding conductor', and is subject to a sizing table based off the ampacity of the largest conductor. This is why tek cable and other large cables have larger than #6 ground conductors in them.

Thanks

Edit* Here it is

 

[Greenman]

No reference right off hand, though there could very well be a qualifier to that rule. I've never seen a residential service larger than 200 amps. I'm sure they exist, but around here it would be a multi million dollar home.

 

[stormkroe]

Yeah, actually services here are smaller than in America on average (huge majority are 100 amp). This bonding size rule is in effect regardless of service size. For instance, you can have a 100 amp service being your first point of disconnect (main breaker). From there on, the ground wire is classed as the bond wire and is subject to the sizing table I posted above, whether it's feeding a plug circuit, furnace, or even a sub panel (which, as you mentioned, would need the neutral/ground tie in bolt removed).
We were taught that the reason for this is because the ground/bond wire now has to take the entire fault current, instead of sharing it with the neutral, because they are separated from that first point.

 

[paperfist]

Electricians might be able to chime in on specific details but I think it's mostly a preference thing and panel space thing. If you run a sub panel you won't use up as many slots in your main. You just need to put a 60 amp double pole breaker and run a 4 conductor cable (not sure of gauge, I know 8 gauge is for 40 amps so guessing you need like 6) and then at the panel you will now have more slots for various circuits that can be used for that room and general area.

Also the breakers don't need to add up to less than the rating, as long as wire gauge is ok. Ex: you can put a 100a panel off another 100a panel that has other 100a panels or other circuits hanging off it, it does not matter as long as breakers are sized properly. It is assumed that every circuit is not going to be loaded 100% all the time, and even if it was to happen the appropriate breaker would trip and not allow it.

I would stick to 15 amp for lighting though, because most light fixtures may not be rated for 20 amps, it's generally not an issue though, but nothing stops someone from screwing in one of those socket receptables and putting a 2000w heater on it or something. I'm not sure how code handles lighting in this respect though. You can still keep the 12/2 wiring, but put a 15 amp breaker.

Thanks that makes sense. I was overthinking all the circuit breakers.

The LEDs I'm using are basically throw away. The are hardwired into the box and have no bulbs to change sort of speak.