Q on adding a 30 amp circuit and subpanel

[G33k Speak]

OK, I read the threads here and poked around online a little bit.

I want to consolidate a couple of seperate 15 amp circuits into a single 30 amp, to power 2 600W' HPS's and a 5500BTU AC unit.

(I would also accept a recommendation on a solid DIY book- esp if it mention the specific requirements to meet NEC.)


As I understand it:

I add a 30 amp double pole 240V breaker to the main panel.
Then I run 240V wiring to the subpanel approx 10 feet away.
I use 2 15 amp breakers in the subpanel to run 2 seperate 15A outlets.

I usually go up a AWG size for wiring 15 or 20 amp circuits- any downside to doing that here as well?

Any reason to not use GFI breakers and/or outlets??
are GFI outlets AND breakers overkill?

and lastly- I want to use the little grey box timer for the lights- should I just wire the timer to the outlet?

 

[PharmaCan]

Just run the power directly from the main panel to a 240v timer. Why screw around with all that other stuff in between? From the timer you can go to whatever you want. If the timer will be in a different room from the main panel, and you want a disconnect right in front of you, just use a dpdt switch. There's really no need for a sub-panel for what you are talking about.

PC

 

[cashmunny]

OK, I read the threads here and poked around online a little bit.

I want to consolidate a couple of seperate 15 amp circuits into a single 30 amp, to power 2 600W' HPS's and a 5500BTU AC unit.

(I would also accept a recommendation on a solid DIY book- esp if it mention the specific requirements to meet NEC.)


As I understand it:

I add a 30 amp double pole 240V breaker to the main panel.
Then I run 240V wiring to the subpanel approx 10 feet away.
I use 2 15 amp breakers in the subpanel to run 2 seperate 15A outlets.

I usually go up a AWG size for wiring 15 or 20 amp circuits- any downside to doing that here as well?

Any reason to not use GFI breakers and/or outlets??
are GFI outlets AND breakers overkill?

and lastly- I want to use the little grey box timer for the lights- should I just wire the timer to the outlet?

GFI will protect you where a breaker won't. I doubt the impedance of the human body is low enough to trip a circuit breaker if you put yourself into a circuit. Maybe someone here can do an experiment to verify that though. Breakers are to keep you from melting your house wiring and starting a fire. GFI on the other hand protects you if you accidentally touch the hot wire and are standing in water or something like that. It compares the current in the hot lead to the current in the neutral lead and shuts off if there is a mismatch. So it protects you from inadvertent grounding. It's a good thing, do it.

 

[madpenguin]

Yea, I think a sub panel is totally inappropriate here. Just run 2 new branch circuits to where you need them. It's really that easy. No need for a sub panel unless you need 240v and 120v loads at the same time.

 

[madpenguin]

I doubt the impedance of the human body is low enough to trip a circuit breaker if you put yourself into a circuit.

It's not. Your body is a fairly good conductor because of all the water and minerals in your blood stream and throughout your body. It's actually a massive surge of amperage that winds up tripping a circuit breaker. When you cross phases to intentionally trip 2 breakers, you'll see upwards to 6,000 amps run through your lines for a split second. That why all breakers have atleast a 10k AIC rating.

 

[G33k Speak]

Part of my reasoning wass that I want the lights and AC on the same circuit, so that if/when the circuits get tripped, I don't end up with the lights coming back on, and the AC staying off- which happens with the digital AC units.

I was thinking that the 30 amp breaker in the sub would pop first, and leave both circuits off.

My GFCI outlets pop occaisionally- seems to be due to an outside influence....I'm trying to counteract this problem with the 30 amp circuit and consolidating the circuits.

 

[PharmaCan]

Part of my reasoning wass that I want the lights and AC on the same circuit, so that if/when the circuits get tripped, I don't end up with the lights coming back on, and the AC staying off- which happens with the digital AC units.

I was thinking that the 30 amp breaker in the sub would pop first, and leave both circuits off.

My GFCI outlets pop occaisionally- seems to be due to an outside influence....I'm trying to counteract this problem with the 30 amp circuit and consolidating the circuits.

The thing is you can do the same thing with a breaker in the main panel, there's just no need for a sub-panel. You're not going to get that sub-panel to do anything the main panel won't do.

The situation you describe of everything going off then just the lights coming back on happens with a power outage, not a tripped breaker. If a circuit breaker pops, it has to be re-set manually. If you turn that circuit breaker back on but not the a/c, you will have exactly the same situation as if the breaker in a sub-panel popped and you turned it back on but not the a/c.

If you want a sub-panel, by all means put one in. But it's not going to accomplish anything over and above what the circuit breaker in the main panel will do.

PC

 

[apartmentblower]

Yea, I think a sub panel is totally inappropriate here. Just run 2 new branch circuits to where you need them. It's really that easy. No need for a sub panel unless you need 240v and 120v loads at the same time.

intermatic timers are easy to wire up to run 120 and 240 at same time. no need for sub panel in any case

 

[G33k Speak]

The thing is you can do the same thing with a breaker in the main panel, there's just no need for a sub-panel. You're not going to get that sub-panel to do anything the main panel won't do.

The situation you describe of everything going off then just the lights coming back on happens with a power outage, not a tripped breaker. If a circuit breaker pops, it has to be re-set manually. If you turn that circuit breaker back on but not the a/c, you will have exactly the same situation as if the breaker in a sub-panel popped and you turned it back on but not the a/c.

If you want a sub-panel, by all means put one in. But it's not going to accomplish anything over and above what the circuit breaker in the main panel will do.

PC

whoops- I misspoke about the circuit tripping- I did mean to refer to a power outage, not a breaker tripping.

I guess even with a subpanel and breakers, that wouldn't solve the outage problem

So I guess simple is better and I;ll run another 15 amp to the room.

Thanks all.