Connecting 6awg cable

I need some help here please... I have a ceiling fan and it is working fine except that after it has been on for about 1/2 hour, it starts to make a ticking sound. Almost like a piece of metal is hitting the case. It is weird that it would start doing this after it has been on for a while. Any help is appreciated. Thanks in advace.

I am adding a subpanel to the main via a 60 amp circuit from the main to a 100 amp 8 slot box. My current 100 amp box only has 16 slots and I need to add a couple of circuits. I want to add the sub directly below the main via a box spacer. I've checked local codes, but have found nothing that speaks specifically about proximity of the sub to the main. The sub will be about 4' from the floor, so it should be fine with regard to the basement flooding (never has though...) Is there any reason not to attch the sub directly to the main via the spacer? Any help is appreciated.