On 2007-11-13, Steve Barker wrote:

Is this acceptable practice to have 2 potential hots in a cable and
no common? (cable#2 in the text).

My understanding of the US 2002 NEC is that this is allowed for
non-metallic sheath cables as long as all current-carrying conductors
of a single circuit enter or leave any ferrous boxes through the same
hole. See 300.3(B)(3).

I've seen 12/2/2 but i believe that contains two commons.

My understanding of the US 2002 NEC is that a white insulated
conductor in a cable can be used as an ungrounded conductor ("hot") if
you reidentify with another color at every termination and point at
which it is accessible. See 200.7(C)(1).

As to your layout, if I understand correctly the physical situation is
as follows:

Kitchen door Ceiling fan Backdoor
2 way fan switch Light 3 way light switch
3 way light switch
Incoming power here

If this is correct, you need 4 conductors (plus EGC) from the Kitchen
door to the Ceiling fan (neutral, fan hot, two travelers for the
light) and 3 conductors from the Ceiling fan to the Backdoor (two
travelers for the light, return light hot). You can get the 4
conductors from the Kitchen door to Ceiling fan with two 12/2 cables,
reidentifying the white conductor in one cable. You can get the 3
conductors from the Ceiling fan to the Backdoor with a single 12/3
cable, reidentifying the white conductor.

Cheers, Wayne