DrewE wrote:
mbrower wrote:
When I installed my residential refer last year, I wanted it to run on an inverter while we traveled to and from destinations. I also thought it would be nice to power a couple of fans and TV while boon docking when traveling. The easiest solution was to power my electrical load center using the inverter through a transfer switch with shore power. This also brought up a couple of concerns that has already been mentioned in previous posts.
To solve the issues with converter and high load issues were quite simple. I wired in a 20Amp electrical outlet to the shore power side of the transfer switch through a 20A fuse. I plugged my converter to that electrical outlet so it is only powered when on shore power. Next, for high loads such as ACs, Water heater and microwave. I wired in a 4 contact, 40A relay used in HVAC systems that receives its power through the same 20A receptacle. I then ran the hot wire to each device through the relay so those devices will only energize when on shore power and not on inverter.
Took about half a day to wire everything in and so far I'm very happy with it.
To be clear, the switched circuits are switched after their respective breakers in the main panel. The basic idea is a reasonable one.
Having the converter not turn off with the main breaker is IMHO a little questionable and I think violates the NEC. It's not a significant fire safety issue particularly as you describe it, but it could be a safety concern for someone doing repair or maintenance work who believes all the 120V power is removed from the coach wiring by flipping the main breaker (and turning off the inverter).
One way around that is to have the converter be on one of the switched circuits via the relay and power the relay directly from the inverter output before the transfer switch. You would, of course, need to switch from normally open contacts to normally closed ones so the inverter turns the circuits off.
I see your point and thank you for the suggestions. Not sure how it could be a fire hazard since the receptacle is fused and all loads are switched after their own circuit breakers.
I had thought about the alternate circuit you described but wanted to limit the current draw from my batteries when on inverter. Also, as the voltage dropped, I was concerned with the relay chattering and reducing its life expectancy.
I could see a potential safety risk if the converter was hard wired but mine just plugs into a receptacle and would be much easier to work on if it was simply removed from the coach. Regardless, many devices are powered by multiple sources and any one working with electricity should assume a device is powered before they verify zero energy with a meter. However, considering human behavior and not wanting to see anyone hurt, it would be prudent of me to attach a warning label to the converter and will do so as soon as possible.
Thanks for pointing that out.
Mark