Community Forums

TDroma · 07-14-2016, 05:18 PM

I am looking for a manual switch or relay to transfer one 120 v branch circuit from shore power to inverter power, while also transferring the neutral. A simple STDP will switch the hot wire but not the neutral. I do not want shore power neutral connected to the inverter or the inverter neutral connected to the electrical panel. I want each isolated from one another.

Any suggestions?
Thanks
Terry

BFlinn181 · 07-14-2016, 09:26 PM

A double pole double throw switch could switch the source of hot and neutral to either of the other two positions. Problem is finding one that can handle the current you plan to switch.

A simple solution would be like RVs were before the installation of automatic transfer switches. Wire both sources of power to outlets. Then connect the circuit you wish to power with a cord and a male plug. Plug in one outlet, inverter, the other outlet, shore power.

dieselclacker · 07-15-2016, 01:31 PM

Quote:

Originally Posted by TDroma

I am looking for a manual switch or relay to transfer one 120 v branch circuit from shore power to inverter power, while also transferring the neutral. A simple STDP will switch the hot wire but not the neutral. I do not want shore power neutral connected to the inverter or the inverter neutral connected to the electrical panel. I want each isolated from one another.

Any suggestions?
Thanks
Terry

I converted one circuit in our motothome, to power our entertainment system from either inverter, or shore power. I used a double pole double throw three position (middle off) toggle switch. I mounted the switch in the compartment with the VCR, sattelite box etc. The inverter on/off switch is located there also. The switch is rated 15 amp, 400 volts. Can't remember where I got the switch, Radio Shack (now defunct) maybe. I needed a pure sine wave inverter for some of the electronic equipment, so had to change out the old inverter for the new 400 watt unit, and modified the power circuit with the switch.

BFlinn181 · 07-15-2016, 01:59 PM

Radio Shack maybe 'defunct' in Montana, but it still has online ordering and stores in our area.

https://www.radioshack.com/

twinboat · 07-15-2016, 03:16 PM

https://www.amazon.com/RELAY-120VAC-...dp/B000JJM7ZS#

Been using one of these on my boat for 9 years.
I wired it to close the N.O. contacts with shore power. Lose shore power and it defalts to N.C., which has the inverter supply.

nothermark · 07-15-2016, 03:30 PM

I'd go the same route as twinboat. That said I would check with any local electrical supply store. DPDT switches are fairly common devices. The power handling you want is common in small motors. If that does not work there is MCM, Mouser, Allied, Digikey, to name a few sources. All of them probably undercut Radio Shack for price but shipping could be an issue with any of them.

dieselclacker · 07-15-2016, 03:47 PM

Quote:

Originally Posted by BFlinn181

Radio Shack maybe 'defunct' in Montana, but it still has online ordering and stores in our area.

https://www.radioshack.com/

Also many to choose from on Amazon, if you go ith the dpdt switch.

TDroma · 07-15-2016, 04:39 PM

Thanks all, a DPDT switch with a middle off would be perfect as I am only running one 15 amp simple circuit to power a TV, DVD and maybe a small fan from the inverter.