I have a question about wiring a new bath fan. It is replacing an existing light fixture that I don't plan to replace.
Here is a picture of the existing box: I tested with a non-contact circuit tester with the power on at the breaker box.
The original light was wired to the single black wire and to the group of white wires. It looks like the same incoming electric cable that supplies the group of mixed black and white wires contains the white wire for the old light fixture--although I'm not sure as two incoming cables kind of join together to enter at the same spot on the junction box.
It's hard to see but there are three armored BX cables coming in to the box and two black, newer looking electrical cables coming in.
What do I do to supply power to the junction box for the fan? It has a pretty small housing and couldn't hold all of these wires. Do I do a pigtail? It does not look like there is room for another wire to enter the existing junction box either. However, there is play in the existing wires--room to stretch to the box on the new fan, which you can see in the left corner of the picture.
I'm assuming that this junction box is where other devices in the house are connected. I see lines heading in various directions. I'm also assuming that the source of power for the old light is in this junction box rather than in the wall switch--that makes sense to me from seeing that one of the wires in there is always hot. Is that right?