I upgraded my bathroom fan to a bigger, more powerful fan. The problem is it is on the same 15a breaker as the 2 bedrooms and the bathroom. It is connected to a light above my tub and the three wires that come up from the dual switch on the wall via a junction box.
The house was built in 1942 and the wiring from the switch to the junction box is original, so the three wires have the cloth coating but look to be copper on the inside. The wire from the fan and the wire to the light above the tub are both newer.
The problem is every time I turn on the fan or the light it blows the breaker.
I even disconnected the light above the tub and replaced the wall switch with a single switch and when I turn the fan on, all the lights dim and it then throws the breaker.
I am wondering if I can replace the 15a breaker with a 20a breaker and how would I go about doing that? I already purchased the new 20a breaker.