These kind of battery switches are popular among the Rv users...
This would be installed so you can completely disconnect the DC Battery from your trailer circuit. Same as removing the battery cable...
![](http://i718.photobucket.com/albums/ww181/tucsonrv/2007_Carri-Lite_36ILQ_5th_wheel/DSC01291.jpg)
My fifth wheel has three things connected to the 12VDC battery being the main DC cable going to the on-board converter/charger unit with the DC Distribution Panel, one going to the emergency disconnect switch switch to provide power for the trailer brakes if the trailer becomes disconnected from the truck when going down the road, and the third cable provides power to trailer slides.
My trailer did not come with a disconnect switch so I always remove the negative battery terminal when leaving the trailer in an extended storage thing.
Roy Ken
My Posts are IMHO based on my experiences - Words in CAPS does not mean I am shouting
Roy - Carolyn
RETIRED DOAF/DON/DOD/CONTR RADIO TECH (42yrs)
K9PHT (Since 1957) 146.52M
2010 F150, 5.4,3:73 Gears,SCab
2008 Starcraft 14RT EU2000i GEN
2005 Flagstaff 8528RESS