@Shajaatx The basic requirement for transferring to UCB is 60 units, GE and Major prereq done. Since you are looking at college of engineering, you will most likely NOT be completing IGETC as your GE. IGETC is mostly for majors in the college of letters and science, and engineering majors have their own set of GE that needs to be completed.
About completing 60 units in one year, it is extremely difficult. Not all classes can be taken together, and you don’t always get into the class you want for that semester, plus the UCs will not count any classes that are taken in the summer after you have submitted your application. I went to a CC and transferred to UCB last year, and during my two years at CC, there was a few times where I had to delay a class because it was too full that particular semester. It’s best to play safe and stay for two years, you have to have a lot of extracurricular activities during CC anyway.
If you stay for 2 years, it’s probably enough time for you to finish all required courses without taking summer sessions, but it won’t hurt to take summer courses if you want to. The college of engineering is hard to transfer into, and you would have to put in a lot of effort outside of school to make yourself stand out. I would recommend talking to counselors at CC (if you decide to take this route) and see what you should prepare before applying, and make the best use of your free time.