I am currently converting my upstairs attic to an extra room so I need to add some wiring. I have been doing research on how to do it and I now understand what I need to do. Now that I understand how the wiring works I have noticed a problem with my current wiring. I will use a bedroom as an example. From the service box to the light switch there is 12/2 wire. From the light switch to the light and fan there is 14/3 wire and from the light switch to the receptacles there is 14/2 wire. I understand that 12/2 can not exceed a 20 amp circuit breaker and 14/2 can not exceed a 15 amp circuit breaker. All of the breakers in my panel are 20 amp except the bigger ones for the HVAC and other big appliances. Technically the 14/2 wire could overload and not trip the breaker. This seems to be a huge problem and a huge fire hazard. I know I need to replace the 20 amp breakers with 15 amp breakers. My real question is how could a licensed electrician do this? This sounds insane to me that someone could be this careless with electricity. Am I missing something here? What should my approach be in contacting my builder and the electrician that did this? My home is less than a year old.

I would ask for a 3rd party's documented opinion first, then check your state reg's on overcurrent protection updating to see it 15A AFCI's will be required.

tforcetek:
You can not tap a switch-leg. The switch leg conductors are part of a branch circuit and not considered a "tap". Although the connected load may be well within the ampacity of the switch leg, the switch must be capable of handling short-circuits and ground faults.
210.3 Rating-"when conductors fo higher ampacity are used for any reason, the ampere rating or setting of the specified overcurrent device shall determine the circuit rating"
-Mark-

T here you go in plain english. Get the local wiring inspector if available. If not get a state inspector. This is wrong, wrong, wrong. Someone either was a moron or just trying to save a few bucks at your expense. This is not acceptable, it is not legal, it is not safe, and it is what gives all of us good electricians a bad name. I also wonder if the builder is aware of what his electrician is up to. I would most certainly let him know.

and....when talking to the contractor [who may want to blow you off]- mentioning the State Contractors License Board in the same sentence usually gets their attention.