As I understand it, I should be safe using the same wiring. However. The no. of wires, and their configuration when I removed the light fixture (5-60watt candelabra-based bulbs), has me seeking assistance. By the way. I did turn off the circuit breaker.
There are three sets of wires coming down into the box from the ceiling. All three have a bare copper wire, a white wire, and a black wire. By the way, the switch is a dimmer. The bare copper wires are all twisted together(please confirm that these are ground wires). Two of the white wires are twisted tog'er. The other white wire is twisted with two of the black wires, while the third black wire stands alone.
The fan instructions call for the house wires to be 1 black, 1 white, 1 ground. Which of the wires/wire clusters from the house do I use as the described 'black', 'white', and 'ground' wires?
Also, it appears the elec. Box in the ceiling, which I plan to replace with a Westinghouse Saf-T-Brace (model 01100) from Home Depot, which was installed when the house was built, may be hard to remove, especially without damaging the surrounding plaster. How do you suggest I go about getting the existing elec. Box out of the ceiling?

The two white wires are you neutral or white wire. The two black wires with a white wire is your hot or black and the stand alone black is the switched black. Connect the white of the fan/light to the two white(neutral), connect the black of the fan/light to the black/white cluster (hot)and the stand alone black to the blue wire of the fan/light. Replace the dimmer switch with a regular switch.

If the existing ceiling box is nailed to the side of a joist cut nails with a sawsall. If it has a flange and is nailed to face of joist cut flange with sawsall. If it is attached to a bar between joist remove screw attaching it to the bar then cut bar and remove.

Thank you, Harold. When I removed two screws from the top of the box, pushed up the wires and moved the box out of the way, I saw/see that the box was screwed to what looks like a steel brace, likely running between the joists to support the approx. 15lb. Light fixture that I had removed.
Issue one is I don't know if this brace is safe to support a ceiling fan. Issue two is the box in the ceiling is not 'approved for ceiling fans', and the box I have to replace it is not as deep by nearly an inch
(I imagine that gets fixed by purchasing a new 'approved' box of approp. Depth)?

There is a number of different fan/light boxes available. The difference is that the fan box gives you the ability of attaching the fan to the brace through the box and not directly to the box. The size and depth of the box is relative to the number of wires in the box. Almost all 4" boxes should have sufficient capaicty for the number of wires you have.

Thanks again. One last question for the night, please. I want to stop for the night, and of course, turn the lights back on. Is it OK to cluster the wires together: Blk, Wht, Grd; Blk, Wht, Grd, etc. then wire nut and tape them, or do they need to be clustered and wrapped-up as they had been to power the light fixture, i.e. as they had been before separating them? Thanks for your time.

Sorry, I went off to take a nap. You can just put wire nuts on them but the outlets or fixtures down the line will not work. Wire nut the two whites together and the two blacks together and take a nap.

Thanks, Harold.

Did you get it figured out?

If not: What wires was the existing light fixture connected to?

What is the existing junction box made of and what is it mounted to?

You will have to remove the dimmer.