Inverter Survey

Apologies in advance for a long post....

I am pleased to report that I have finally finished my inverter installation. The remaining task on the wish list had been to install an auto transfer switch.

I was concerned about the way things had been wired previously because the installation was not "idiot proof". In my 2720 the optimal location for the inverter was beneath the curb side settee in order to have a short distance to the batteries. However, this is diagonally opposite the location for the converter which is under the tub seat. Routing of Romex between those locations is not an immediately obvious and easy activity. Consequently, I did the simple thing and just ran a cord with a plug from external outlet box that is also in the curb side settee. This brought with it some concerns however.

1. If the plug into the inverter were removed and the TM was on shore power, I could have a hot plug (unless the circuit breaker was off in the distribution panel)

2. The inverter could attempt to charge the battery via the converter (unless the circuit breaker was off in the distribution panel)

Things generally worked fine as long as I remembered which configuration the circuit breaker was in. (We don't generally camp with electrical power so this in practice was not a big problem for us.)

However, I wanted a safer configuration so I finally ordered an ATS. There happens to be one that is perfectly matched to mount into slots that exist on the back of the TM's WFCO converter. http://www.wfcoelectronics.com/index...=102&Itemid=86 It fits perfectly.

The hard part of the job was routing that Romex I mentioned.

There is a tunnel from under the sink to under the tub. Other than some expanding foam at the entrance to the tunnel, the tunnel proved to be easier to work with than I thought it would be from a cable snaking perspective. 12/2 Romex was stiff enough to allow me to push it right throught the expanding foam into the tunnel and all the way to where the tub is. The hard part was getting access to the tunnel on the tub side. The tunnel is about 1.5-2 feet from the hallway so it requires some reach to get to it. There is so much existing wiring running in and out of the converter and distribution panel that unless you want to undo a lot of wiring you are going to have to squeeze your arm into a painful hole to reach that tunnel. Moreover, you then have to hope your fingers find the loose end of the Romex. After some cussing though, I was finally able to get the Romex near to the converter. At this point, the hard part of the job was done because I finally had a loose pigtail by the converter and a loose pigtail under the sink.

The loose pigtail under the sink was then routed behind the refrigerator to a new electrical box I put in there so that I could connect it to the Romex that originally ran between the electrical outlet next to the 12V outlet near the street side settee into another tunnel over to the curb side settee. I decided that I only wanted the external power outlet to be hot when the inverter is running. The kept me from having to run 15 more feet of Romex to the inverter. I did not want shore power to energize the plug going into the inverter under any circumstances and this approach accomplishes that goal.

The loose pigtail by the converter was connected to the "generator" input of the auto transfer switch. I then disabled the timing circuit on the auto transfer switch. Since I am not connecting this to a generator, I do not need to impose a 20-30 second delay for a generator to stabilize on startup. The auto transfer switch has a dip switch to enable/disable this feature.

I connected the "shore power" input of the auto transfer switch to the output of the 20A circuit breaker outlet.

I then connected the output of the auto transfer switch to the GFCI outlet that was previously connected to the 20A circuit breaker. The inverter has its own GFCI outlet so no matter which direction the power is coming from, I am GFCI protected.

Everything works like a champ. If I had found that tunnel and investigated things sooner, I would have done this update a long time ago.

The way it operates is that shore power is used unless the inverter is on, in which case, the inverter carries the load. When I put my circuit tester in an outlet and cause things to transfer from one source to another, it looks like about a tenth of a second or so flicker as the relay changes position.

I hope this post made sense but knowing me, it probably didn't.