"CB" wrote in message
...

If this is a new remodel, and walls are going to be open, you might as
well run new 20A. Don't bother trying to use the old 15A wire as a
drag line, just cap it off in the panel. I believe code now calls for
20A in a bathroom. If you are going to have a fan/light/heat combo
unit, that alone needs its own circuit
It would be different if you had to tear walls open if you have to run
a new line, but since you have access to run cables, might as well do
it.
I would also like to add if you are putting a fan/light combo inside
the shower/tub area, it must be GFI protected. You can just get the
feed off of the GFI outlet to accomplish this.

The bathroom walls are definitely out - I stare at insulation and
studs every night when I get home - ugh.

I may be missing something - if I am please forgive me. You said the
fan/light combo must be on a dedicated circuit, but then you said that
I could catch the GFI for the fan/light off the outlet run, implying
that now it's on the same circuit as the outlets.

And just wanted to confirm - I shouldn't mess with trying to fish the
15A cable out and then fish a 20A wire down via the attic? Did you
think that I should run across the crawl space and then up the HVAC
chase two floors?

First of all, it would make little sense to have the existing outlet circuit
daisy chained from one bathroom to another unless it was in fact protected
by a GFCI device upstream of these outlets. This was done commonly in the
80's. If you want to run new circuits to upgrade the bathroom, the easiest
thing to do would be to run one 20 amp circuit and just use it for the
outlets in the renovated bath. You can use the existing lighting circuit for
any new lights and fans, etc. provided you're not adding any electric heat
or Jacuzzi, and things of that nature. You cannot disconnect either of the
existing circuits at the panel, as they are feeding things other that the
renovated bathroom, so you have to locate junction boxes in some accessible
place to splice those circuits through, to wherever they're going.