How to Wire the AC on a Travel Trailer

Travel trailer air conditioner units, or ACs, run on 120-volt electricity, the same as small household units. Travel trailer ACs are typically roof-mounted and may circulate cooled and dehumidified air either directly into the living space or into plenum ducts for distribution to separate rooms. Roof mounting can make wiring problematic because it involves the removal of interior trim and fixtures. Some ACs have integral thermostats, while others have remote units, which also must be wired to the roof unit.

Instructions

1

Remove the shroud from the AC and locate the data plate, which should describe both a British Thermal Units, or BTU, value and a running amps rating. Use this information to determine the wire gauge necessary to power the unit safely. Travel trailer roof ACs are usually rated at 13,500 BTUs and consume 11 to 14.9 amps. For such a unit with a typical 30-foot run of copper, wire should be 14-gauge or greater.

2

Design a route for the wires to follow between the circuit breaker board and the AC unit. Because travel trailer fixtures and fittings usually are installed after the walls have been fully constructed, routing new wires can be challenging. Both the power supply and the thermostat wires should be installed in the same channel to minimize disturbance. Avoid runs through areas where the walls are already likely to be populated with conduit, pipes and wiring such as the bathroom, the galley or near any electrical devices.

3

Remove any obstructions to the free installation of the wires; dragging and tugging wires past obstructions and around corners is to be avoided.

4

Install the sheathed electrical cable as far as possible through drawer units, closets and cabinets where access to hidden areas can be gained by removing replaceable furnishings such as drawers and the backs of cupboards. Use an electrician's fish tape to draw the wires through awkward spaces. Route the wires across the ceiling by breaking a pre-existing join in the ceiling panels and tucking the wire in, or run the wire to the unit through plenum ducting.

5

Connect the sheathed electrical cable wires to the AC unit at the terminal hub, observing the manufacturer's instructions. Typically the hot wire should be attached to a copper-colored screw, the neutral wire to a silver-colored screw and the ground wire to a green colored screw.

6

Connect the thermostat wires to the AC unit as per the thermostat manufacturer's instructions. Typically the compressor wire is color-coded yellow.

7

Connect the power wires at the circuit breaker by attaching the neutral wire to the neutral bus, the ground wire to the grounding block and the hot wire to an dedicated, not shared, circuit breaker. Do not install the breaker in the breaker board.

8

Reinstate all trim, panels and fixtures and install the breaker, then test the function of the unit as instructed by the manufacturer's literature.