With all this wonderful summer heat here in Northern California I've decided I might need to install an AC in one of my upstairs rooms. The complication is that half of the upstairs (two rooms, hallway, bathroom, stairway) are all on the same 15amp circuit.

Short of rewiring that portion of the house would it be simple enough to remove the 15amp breaker and install something of a greater capacity?

If that answer is no, then my project gets potentially more complicated in that the service panel doesn't have any free expansion slots available. If that's the case, what scale of a project am I looking at?

I appreciate any suggestions, ideas or advise, thanks!

- Chris

"Short of rewiring that portion of the house would it be simple enough to remove the 15amp breaker and install something of a greater capacity?"

No, no, no.

That is a good way to start a fire.


"Short of rewiring that portion of the house would it be simple enough to remove the 15amp breaker and install something of a greater capacity?
"

That is the least of your "potential" problems.

Depending on the details it make be as easy as replace a breaker with a tandem breaker. Or it might adding a sub-panel.

But is the existing panel and service large enough handle the load (it might already be over loaded).

And then you have the problem of getting the wiring to the 2nd floor.

You really need someone locally to evaluate it. It might be simple and cost a few hunred or it might be that you need major upgrades and are talking about a bill in the thousands.

This is precisely why I posted my question here. I had a feeling that it wasn't going to be as easy as I had hoped it to be. Looks like if I'm going to pursue this project I'll be calling out a local electrician; any upgrades of this scope sound well beyond my current skill set.

Thanks for helping me to *not* burn my house down. :D

I've come about a follow up question since I've begun to pursue different options, less dangerous ones... hopefully. As I've been studying over my breakers I've come about some that might not be in use and others that may be severly _under_utilized.

I have yet to set my sights on a specific AC unit, however there is the very real possibility that it will require a 240 outlet. Since the documentation on the breaker panel is lacking in explanation, how might I determine if the wiring to a specific breaker is 120 or 240?

Thanks again!

Most breakers are 1" or 3/4" wide and are single pole (120 volts) and will only have one wire going to them.

GFCI and AFCI breakers are similar in size but will have two wires going to them and a third that connects to bus. They are still 120 volts. But you can tell that they are "special purpse" because they have a test button on them.

Then there are tandem breakers. Those are two separate breakers in the same slot as a standard breaker. It will have two handles, each on independent of each other. That will supply two different 120 volt circuits.

A two pole breaker is required for 240 circuits. It will be double wide and either have two handles with a connection between them or on handle. And it will have two wires connected to it.

Newer panels are labeled with both the number of positions that it has for breakers and the number of poles that it is designed handle. For example one might be a 30/40. That is has 30 slots, but in 10 of them you can use tandem breaker and have a total of 40 poles (circuits).

You can do two things to get more space. If you panel will support it replace 4 single pole breakers with 2 tandem breakers and that will leave two spaces for a 2 pole breaker.

Or if as you said some circuits are under utalized then can be combined. Note that most breakers are only designed for 1 wire so you need to combine them before connecting to the breaker.