Splitting existing 220v 30amp into 110v?

Building out a grow room in the garage and need as much power as I can get, primarily for heating.
This is the panel. I want to know if I can take the bridged 15+15amp breaker that's currently powering a useless 220v outlet and make it 2 single 15amp circuits? I get that it's super easy to just make the red a ground and then change the outlet to a 15amp, but does that mean I also free up another spot for a new 15amp circuit/outlet?
If I disconnect that 15+15amp breaker, can I stick 2 single breakers in? Or do I have to get 4 new breakers that are all 15amp? The fact that the two breakers are bridged is what's really confusing me, why is the 220v outlet it's own 30amp breaker?

It's bridged so if one leg trips, it will trip the other leg.
You could put 2 30a breakers in or 4 15a breakers. Your choice.

Don't know if i understand what you mean about making the red a ground. Red and black are both HOT legs.

With four 15 amp circuits on what was designed to be one 220V, 15 amp circuit, you already have overloaded circuits that are in violation of code.

Putting 30 amp circuit breakers anywhere in this application is asking for a fire.

It isn't worth someone dying to grow some pot.

I wouldn't go to an electrical forum to ask them what my plant deficiency is, and I wouldn't go to a weed forum to ask about wiring a room.

CrushnYuba said:

Don't know if i understand what you mean about making the red a ground. Red and black are both HOT legs.

Click to expand...

Yeah my bad, it's already grounded. I meant that if I want to convert the 220V outlet to a 110V using the existing wire, in the breaker box all I have to do is remove and cap the red wire and switch the black to a new 15amp single pole breaker. Then at the outlet I can use just the white and black for the new 110v outlet. Right?

Defacto said:

With four 15 amp circuits on what was designed to be one 220V, 15 amp circuit, you already have overloaded circuits that are in violation of code.

Putting 30 amp circuit breakers anywhere in this application is asking for a fire.

It isn't worth someone dying to grow some pot.

Click to expand...

That is how the subpannel was already wired (as you can tell by all the spiders, I haven't worked in there at all). As mentioned, I really don't understand how bridged tandem breakers work. To clarify, the 220v circuit is split across both tandem breakers, hence the pin (and there's a little diagram of a 240v bridge on the breaker, so it seems designed for that purpose). I don't get how/why it's spanning and sharing a breaker with 2 other circuits would help with not overloading the circuit.

Looking at all the breakers, I don't know if this panel is a 60amp panel or a 45amp panel.



Even weirder to me is how the breaker is mapped:
Top Left: 2 fluorescent ceiling lights (yes, 15amp for 2 ceiling lights)
Top Right: External/buried line that powers the barn lights/outlets
Bottom Left Tandem: 2 entire walls (4 outlets total) of the garage
Bottom Right Tandem: 1 entire wall of the garage (3 outlets) and garage door opener.

And then there's that bridge which goes to that 220v outlet that I don't know what it was used for.


I don't yet know how many amps are running to the garage. The subpanel is controlled from inside a second house on the property that is currently being rented, so I'll probably only get to look at it this weekend once the tenants have given their permission for me to enter. If it's 60amp or more, I'm stoked and think I can rework this panel a bit (like taking the ceiling lights off their own circuit). If it's only 45amp, that's going to be a serious problem.
Thanks for the help everyone

If I were you, I would check to see how it's wired in to the main panel. Check the wire gauge running to the sub and how long it is... See how much available power you really got

On the bottom breakers, the ones with the tie-bar are a 220v circuit and the 2 on the outside are are 110v circuits. IMO

I don't think defacto looked at the picture. Don't let him get you down. You got 90 amps of breakers in that panel. 45a on each leg.

The quad breaker with the center common trip is definitely not something you will see every day. Not sure exactly why they chose that one. The other breakers are upside down. 90 amps is allot. Make sure you got the power to spare, or when you start maxing out all the breakers in that sub panel, you will trip a breaker in the main. That's the worst that would happen.

But yea, as long as it's balanced, however you want to configure that 45a on each leg is your business.

Where I live, a 60 amp sub panel needs a 6 gauge copper wire to supply it.
Those wires in your panel look 10 gauge.