My house was completely rewired by the previous owner. They tore out all the old knob-and-tube and replaced it with modern wiring. I definitely appreciate this, but unfortunately they left absolutely no extra space on the new breaker box. Every single slot is filled with a circuit breaker.
It's not that the circuits are doled out too liberally either. Its just a small breaker box. It fits the requirements of the house exactly, but leaves no room for future expansion.
So, what are my options for adding more breakers? Can I add a sub breaker box? Or should I just replace the whole thing with a larger one?
Best Answer
You have two options:
There are caveats with both routes. When using tandem breakers on a 120 volt system (i.e. with a neutral present), you want to avoid something that is called a multifeed. This is, two circuits on the same phase sharing the same neutral. When using tandem breakers, its very easy to inadvertently do this.
If you are in the US, you will see two feeders from the meter, one of them probably has some red tape on it, the other is black. These are your phases. Normally, every other breaker is on a different phase, but tandem breakers put both circuits on the same. Take care that both circuits attached to a tandem have their own neutral (white wire).
While you might be able to install a tandem breaker yourself (I highly recommend calling a qualified professional), you will surely want an electrician to install a sub panel. They aren't much different from a regular panel except:
In either case, I really recommend calling an electrician.