I recently bought a house and have found several things wrong and I'm trying to prioritize which to fix first. I have some very limited electrical knowledge but not enough to know if this needs to be fixed immediately or can wait. I live in Texas. I'll try to use correct terminology but no gaurantees
I went into my attic to see about adding a recepticle in my (attached) garage. I find the junction box and see that the romex is just running straight from the direction of the main breaker box over insulation and whatever else is up there no staples. This is very thick 10gauge romex.
Inside the junction box it is wire nutted to three other cables one 10gauge, and two 14gauge cables. The 10gauge is then ran to a ceiling cicle box which holds the recepticle my garage door opener is plugged into, then continues on to be spliced (using only wire nuts and electrical tape). One (14gauge) leads to a switch and the other (10 maybe 12gauge different color romex) to an outside light controlled by the switch.
Back to first junction box. The two 14 gauge romex cables are ran to 15amp recepticals on two different walls (I was wanting a recepticle on the third wall). One of these recepticles has a single red very thickly insulated regency wire ran from it to a switch and continue on to the overhead light fixture. A single white common wire (same type very thick insulated wire) is ran to the fixture from the other receptical for some reason, and no ground wire.
At the main breaker box I find the 10 gauge cable is attached to a 30amp breaker and is just ran out of a hole punched out of the bottom of the box, ran up the side of box, and into the soffit.
I need to know if there are any immediate hazards I should fix this weekend. Then what is going to need to be switched out to get to/near code. I know the electrical taped splice needs to be boxed, but the 30amp breaker i haven't a clue if it's a hazard or if its fine since only 15amp recepticals are attached. The 30amp breaker is not ground or ark fault.
Best Answer
Good diagnostic post! You have a number of safety issues, chief of which is all those receptacles and 12/14awg wiring should not be fed by a 30A circuit breaker. How fast you decide to fix them is up to you, but you're right that it is a fire hazard.
For example, a 14awg NM-B cable can carry 15A without exceeding a 60C design temperature (someone will surly correct me if I'm remembering the values wrong.) The requirements for installing this type of cable (no conduit needed, okay to be in contact with insulation, etc.) are specified with that 15A in mind. When you exceed it by using a 30A breaker, some person could plug two big space heaters into a receptacle, cause the 14awg cable to overheat, and it could start a fire, all without tripping the circuit breaker.
My suggestion is to start by replacing the 30A breaker. If you change it to 15A the wiring you have currently (aside from the improper splices) is basically safe. If you change to a 20A breaker you will need to upgrade the 14awg wire to 12awg.
Book recommendation
By the way, you may want a book to help you get started. As @ThreePhase explains, there are plenty of other things you want to do to make all this safe and up to code; and it's hard to cover them all in Q&A form. I like the Black & Decker Complete Guide to Wiring, which is available at home improvement stores and many libraries. It's heavily-illustrated and aimed right at DIY homeowners.