isolating inverter from ac power source

[bobhenry]

I tend to design in my dreams and last night I decided 12 volt lighting in the new 5x10 tear. However there are a couple reasons to have some AC available , so an inverter would come in handy. However , where A C is available can it feed into the A C wiring without isolating the output side of the inverter without damaging the inverter. I am sure that with simple switching isolation is easily done but if it's not necessary that one less headache to purchase , install and operate.

[Dale M.]

I would put in a disconnect switch (transfer switch) so when your are running inverter power it is connected to ac outlets and appliances in trailer. When you connect to shore power you would flip the switch over and disconnect inverter output and connect ac receptacles and such to shore power...

Generally the outputs of inverters are not in sync or compatible with external power so I would not try to have both connected together at any time.

Dale

[asianflava]

I installed a DPDT switch so that I can switch from Battery (inverter) Off Shore Power.

[bdosborn]

Inverters are not synched to utility power so you'll let the smoke out if you ever connect the two. Home Depot sells a 120V DPDT switch you can use to switch sources like Asianflava did.
Bruce

[britlynz]

Depends on the style of inverter. Some come with an internal transfer switch. Basically you connect shore power to the input of the inverter and you connect the output to your breaker panel. Take a look at some the models that Xantrex offers.

[SSchumacherCO]

You could use a relay to switch between the two. Attach the coil to shore power. The default (non-energised) path would connect the output of the inverter to the load (outlet, TV, etc). When shore power is connected the inverter would be disconnedted and the load would be connected to shore power. I would probably add a second relay to disable the battery connection into the inverter so it no longer is an unecessary draw on the battery. This may sound more complicated than it is. If I could figure out to draw a picture... All you really need is a relay with a 120VAC coil and DPDT contacts rated for the output of you inverter (15A should do the trick).

[SSchumacherCO]

Here is a comercially available transfer switch. It will disconnect from the inverter if shore power is present. Basically the same idea as what I tried to describe above. The only real downside I see is that the inverter would not be automatically turned off when not in use. No big deal, in therory the battery charger would be feeding the battery thus keeping the unused inverter from draining it.

IOTA 30 Amp RV automatic transfer switch
http://www.coloradostandby.com/catalog/ ... ath/1_2_30

[tonyj]

I took a slightly different approach.

I severed the connection tabs on my first duplex outlet from shore power. On side is fed by shore power, the other by the inverter. All my other outlets wire into one plug that plug into either the shore or inverter outlet. This way I have isolated the circuits.