Autoformer & Intermatic Surge Protector Installation for
2004 Keystone Montana 3295RK
I decided to buy a Hughes Autoformer for our new fifth wheel but was unhappy leaving it outside where it could walk away. I also didn’t like the idea of it being out in inclement weather and having to move it out of the basement storage area to hook it up every time that I wanted to use it. The unit weighs 40 lbs.
A permanent installation was needed. I found the solution by installing the Autoformer inside the unit near the electrical panel.
The Autoformer model I chose was the RV 220-50. Our 2004 3295RK has (2) 50 Amp main breakers that feed the trailer's circuits. In reality this allows up to 100 Amps to be used by the trailer if hooked up to a 50 Amp campground circuit. We will never pull 100 Amps in our unit since we do not have the bedroom air-conditioning prep and although we have the W/D prep, we have decided not to install a W/D. Therefore one 50 Amp leg would not be used at all unless we decided to plug something in the W/D outlet in the closet.
Some earlier Montana models previous to 2004 and late 2003 have a slightly different electrial panel. Their main breakers consist of a 20 Amp main breaker and a 30 Amp main breaker. The 20 Amp main breaker feeds the breakers for the bedroom AC and the W/D and the 30 Amp main breaker feeds the breakers for the rest of the trailer. For owners of these models the Autoformer RV 220-50 still would be the right model to use.
The install procedure began by removing the electrical panel. It comes out by removing the door and 4 screws. It pulls out and can be laid on the floor without disconnecting any wires. (For safety reasons, I first killed all the power by unplugging the A.C. power cord and disconnecting the battery.) Once the electrical panel was removed, I was able to pry off the wood panel next to it to have an opening for the Autoformer to sit in. I found that I had ample room for the installation of the unit and the wiring.
I didn’t want the unit moving around, so I used some pipe strapping to hold it in place. I added a junction box to the handle of the Autoformer. Next I disconnected the wires that provide power to the main panel. Since I have a 50 Amp supply, there were 4 #6 wires - 2 hots (red & black), a neutral (white) and a ground (bare copper). After removing the wires, I fed them to the junction box that I mounted on the Autoformer and wired them to a 50 Amp female receptacle which I mounted in the junction box. The next step was to simply plug the male pigtail of the autoformer into this receptacle. The last step was to wire a #6 4 wire cord with a male plug on the other end to electrical panel and connect the male plug to the female receptacle of the Autoformer.
Although the Hughes Autoformer does provide a limited amount of surge protection for the unit and the coach, Hughes recommends additional protection. In fact the unit is not warranted for damage caused by surges or spikes. It is for this reason I added an Intermatic Surge Protector. I used their Model IG1240R which met my needs as far as physical size of the unit and protection. This unit works well for RV applications because it will not trip any GFCI that may be incorporated in the campground electrical system. This surge protector will work with large amounts of current since it shunts this current to ground. I mounted this unit on the side of the junction box and wired it in parallel to the female receptacle that provides power from the campground. This provides protection ahead of the Autoformer and also protects the contents of the coach.
This surge protector doesn't need to be wired into any breakers, although the instructions say to do this. If the surge protector was wired at the breaker panel then it would not protect the Autoformer because the Autoformer by it's nature has to be wired ahead of the main breakers in order to boost the voltage before it gets to the main panel. In other words' if the surge protector were to be wired at the breakers it would protect the coach but not the Autoformer. The surge would have already destroyed the Autoformer before it reached the surge protector at the main panel.
As far as the heat from Autoformer, the techs at Hughes told me that they cannot tell how much heat is put out, nor can they tell how large the opening for the Autoformer needs to be for any heat dissapation. The amount of heat put out by the Autoformer would be determined by how much and how long it was boosting voltage (how hard it was running).The electrical panel has a fan that draws some of the excess heat out of the area. Time will tell if it will be too warm or not.
One thing to remember - the Autoformer does not provide against incorrect campground wiring. I always check for correct polarity of the wiring before I hook up. Also the Autoformer does not boost voltage under 94 VAC.
Lots of tools are required to do the job.
At this point, a majority of the job is finished.
Right: Wire on right side of junction box was originally hooked up to the main electrical panel. Male plug on top of junction box comes from Autotransformer itself.
Plumbing strap, don't want it to move!
It is screwed into the floor.
Right: Almost done, the electrical panel has been put back in place.
The lights on the left side of photo show that the unit is boosting voltage.
Electrical panal cover back in place.
Left: Intermatic Surge Protector wired in.
Surge protector has two indicator lights to show it is working correctly.
Right: Finished project, door made by a local cabinet maker installed.
Hardware that matches the factory installed hardware.
Copyright 2003 to 2019
