Dometic FreshJet3 Series Installation Manual page 12

Pre-installation
8 Structural framing for a new roof opening
0.8 in. (20 mm)
q
Minimum width for the
framing stock
0.3 in. (8 mm) Minimum
w
width for access hole
5. Frame the opening so it will not collapse when
bolting the rooftop component down.
6. At the front of the frame opening, leave or create
an access hole to allow for the length of exposed
115 VAC power supply wiring required to complete
the installation.
7. Using the roof opening as a guide, cut a matching
hole in the ceiling of the RV interior.
6 .4 Routing the supply wiring to the
roof opening
I The power must be on an appropriately-sized
separate time-delay fuse or circuit breaker. See
"Specifications" on page 8.
This section describes how to route the wiring for the
rooftop component.
12
q q
w w
e e
15.0 in. (381 mm)
e
Exposed length
of 115 VAC power
supply wire
Rooftop air conditioner (air distribution box, wall thermostat controls)
6 .4 .1 Routing the VAC power supply wire
1. Route the 115 VAC power supply wire, with ground,
from the time-delay fuse or circuit breaker box to
the roof opening. Use a listed/certified non-metallic
sheathed single strand cable. See "Specifications" on
page 8.
I If an AC or a vent fan were removed, the existing
power supply wire may be used provided it is of the
proper type, size, and location, and if it is correctly
fused.
2. Make sure at least 15.0 in. (381 mm) of the 115 VAC
power supply wire extends into the roof opening to
ensure an easy connection at the junction box.
6 .4 .2 Routing the VDC power supply wire
1. Choose one of the following options to route the 18
to 22 AWG VDC power supply wire:
– For an independent 12 VDC power supply, route
the wire from the filtered side of the RV converter
or from the battery to the roof opening.
– For an RV-C 12 VDC power supply, route the wire
from the vehicle RV-C bus to the roof opening.
2. Make sure that at least 15.0 in. (381 mm) of the
12 VDC supply wire extends into the roof opening.
6 .4 .3 Routing the thermostat
communication cable
1. Route an 8-conductor, RJ-45 communication cable
from the roof opening to the thermostat mounting
location.
For RV-C bus communication, where a multiplexer
will control the AC, route two 18 to 22 AWG
conductors to the roof opening from the bus.
2. Make sure at least 15.0 in. (381 mm) of the cable
extends into the roof opening and 6.0 in. (152 mm)
extends from the wall at the thermostat mounting
location. See "Preparing the thermostat opening" on
page 10.
EN