at the exact same time to produce the flame effect.)
Take your hacked power supply and with the cover
removed, drill some small holes in the bottom of the case.
Be careful not to drill through anything but the case itself.
Now, place the power supply inside of the enclosure (we
have a lower shelf installed in ours to attach this to). The
power supply needs to be securely mounted. We also
need to place the electrical box inside the enclosure as far
away as possible from the power supply. Set the electrical
box aside for now.
We need to mount the power switch to the side of
the enclosure. Since we’re only going to have one power
cord coming out of the prop, we cut the cord to the
power supply about one foot from the plug end, stripped
the wire back, and tinned all of it to prep for soldering
(Figure 14).
We now need to run all the wiring into the electrical
box so we can solder it all together. On the top and
bottom of the electrical box are little knockouts. We’ll
need to remove these on one side and feed the cut ends
from the power supply through one of the knockouts,
then run the two black and white wires from the lighting
harnesses through the other knockout and into the
electrical box as shown (Figures 15A, 15B, and 15C).
Next, take the white wires from the two light
harnesses and solder them together with the two common
wires: one from the plug end that we cut off and one
from the cord running to the power supply. Shrink wrap all
these wires once they are soldered. (The common wire is
the one coming
from the wide
spade on the
power plug. Of
course, not all
power supply
cords are the
same and might
have different
colored wire for
the common.)
To connect
the black wires
from the lighting
harness and hot
wires together,
we will make a pigtail. Cut a piece of
black wire about three inches long
and solder it together with the two
black wires from the lighting harness
and the hot wires from the power
supply cord. Shrink wrap all of this
together, leaving just the end of the
new black wire hanging out; this is
the pigtail.
The pigtail will need to have a
terminal ring added by using
crimpers, then crimping the ring to
the wire. The ring will attach to the
switch, so make sure the ring is the
right size for the switch’s screw.
So, now you should have three wires left; two of them
are ground wires from the power supply cord. They can
be soldered together and shrink wrapped since we won’t
be using them. The third wire from the plug end of the
power supply cable will be used to connect to the switch.
Attach a terminal ring to this wire (it should be the hot
wire coming from the plug end that we cut from the
power supply cord).
The switch we used is a double pull/double throw and
has six screws on it. We will need to take a short piece of
black wire (about two to three inches long) and use it as a
jumper wire. This will connect to the two end screws so
that when the switch is flipped in either direction, it will
turn on the prop.
Attach the blue terminal ring from the black pigtail
wire to one of the end screws, and attach the red terminal
ring from the hot wire coming from the plug to the middle
screw. All the wires will be attached on the same side. Do
not attach any wires to the other side of the switch. It
should look like Figure 16 when wired correctly.
Be sure you make room for the switch! We did run
into a problem here. The switch we picked did not have
enough threads to go all the way through the side of our
wood enclosure. This required us to notch out an area the
size of the switch to recess it from the inside of the
enclosure and have enough threads stick out to put the
nut on to mount the switch.
When completed, the back of the switch should be
inside the electrical box, and the power plug will hang
down near the side of the enclosure.
September 2014 77
FIGURE 14. We cut
about one foot off
of the cord coming
from the power
supply and
stripped the wires.
FIGURE 15A. This shows
how we ran the wiring from
the harnesses and the power
supply into the electrical
box knockouts.
FIGURE 15C. Wiring the grounds
together from the power
supply cable.
FIGURE 15B. Wiring the hot wires
together with the black wire
harnesses.
FIGURE 16. Wiring
for the switch.
FIGURE 17. View of the electrical box
before it is mounted inside the enclosure.
Note that the electrical box will go over
the switch to protect the wiring.