Conversion of 30A Trailer Supply

This weekend's modification project on the Jayco Jay Flight 28BHS trailer was to replace the shore power cable with a detachable system based on parts from Marinco as others have done.

Here is the problem. This trailer, unlike our last one, uses this so-called "mouse hole" for the 30A electrical cable used to connected to shore power.  This cable is permanently attached internally and you pull the whole length of the cable out through this hole.  Jayco warns that the cable should not be used partially extended.  Probably because heat is not adequately dissipated.

I really hate this cable system.  When the cable gets muddy, you either have to clean it carefully prior to stowing it or end up pushing mud into the trailer. Worse, when the weather is very cold, the cable gets stiff and is impossible to shove in the hole. I also find it tedious when I need to quickly connect shore power to the trailer at home.

To begin, I removed the three screws from the mouse-hole assembly and pried on it a bit ... it came right out.  There was no lap sealant used here.  Rather, butyl tape was used to water-proof the assembly.  The term "tape" seems like a misnomer to me.  It is more like stringy putty on a roll. The RV service guy recommended that I seal the new receptacle with butyl tape as well.

One of the challenges was the size of the hole shown here.  It is too big for either of the two conversion kits available so I had to fabricate some sort of a plate.

Here is the round version of the 30A receptacle which I used.  Next to it is a thin aluminum adapter plate I made from on-hand scrap - the bottom of an electronics project box.

I made the large hole by drilling a series of small holes along the outline, bashing out the bits between the drill holes with hammer and chisel, and filing the inside smooth.

I next bolted the receptacle onto the adapter plate, using a single thickness of butyl tape to seal it. I cut the existing electrical cable 12 inches from the trailer, and attached the end to the back of the receptacle. No pictures for this part, but pretty much followed the installation instructions I found on-line.

Here is the assembled adapter plate.  I used 3 layers of butyl tape in the recessed areas and 1 layer for the rest. The main problem I ran into was that the thick particle board you can see just behind the aluminum siding in the second image did not extend very far around the hole.  Only the two upper-right screws in image actually hit wood.  I have since added a extra screw in the middle of the adapter plate, just under the lid.

This image shows the new locking and weather-sealed plug attached to the original cable. There is a lot of butyl tape visible under the plate.  I think I will add a bead of silicone caulk around the plate as well in order to protect the butyl from damage.