I've installed a dedicated 20 amp circuit for a heater/fan/night light/
light combo. Naturally, I used 12 gauge wire to deliver the power to
the unit. But I am faced with this problem. There are four sets of
wires that need to run from the switch box to the unit which means a
total of five sets of wires which the box just won't take.

Is it OK if the unit is connected to the switch with 14 gauge wire. Or
if I use 12 gauge for the heater part and 14 guage for the rest?

Many thanks in advance!

Aaron




No, it's not OK, but you don't need four sets of wires, all you need is
six
wires including ground. I would get a length of 1/2" greenfield and run it
from the switch box to the fixture-



Thanks! (But what is "geenfield"?)



Flexible metal conduit that you pull your own conductors through. It looks
similar to the armor on BX cable, but it comes in bigger diameters. I just
ordered some 1 1/2" Greenfield today for a job I'm doing. You will need to
pull four colored conductors (Other than white or green) plus one white and
one green. Use stranded wire as it is easier to pull through flex.

If the switchbox is too small you should change it. You could use a 4"
square x 2 1/8" box with a switch ring or a 4 11/16" square box that is 2
1/8" deep with a switch ring. There are more choices for boxes at an
electrical supply house than at Home Depot.

Each #12 conductor requires 2.25 cubic inches in the switchbox. For each
device such as a switch a deduction of two wires must be made. The
grounding conductor only counts as one. At the very minimum with one device
you will need space for 10 wires x 2.25 cu. inches = 22.5 cubic inches. If
you plan to have more than one switch you need 4.5 cubic inches for each
one.

Tables 314.16(A) & (B) should help.