Power jack disconnect

[BobG]

A switch between the battery and emergency trailer brake's breakaway switch is not allowed by code. I can't recall which code. I remember this from when I rewired my breakaway switch. The code didn't directly say a switch was not allowed. It phrased the requirement something like "The breakaway switch electric circuit must remain on and not be able to be turned off."

Bob

[rubicon327]

Originally Posted by JohnK

Thank Jon you for setting me straight. Opening that junction box I had visualized the wire going aft to the trailer as an extension of the tongue jack wire instead of realizing it is the power wire coming from the battery to the junction box which it definitely is. And what you say about the jack still able to be powered from the 7 pin if the switch is installed on the trailer side of the junction box should have been obvious to me. Instead I overlooked that fact. Thank you for your complete answer.

Probably a bit challenging on a 21C with batteries in the rear but thanks to Jon it sounds like you have realized that to do what you want to do you would need to run a dedicated power wire the length of the trailer to power the tongue jack independently. It is on this wire that you would install your switch which would then kill all sources of power to the jack. FWIW I installed my own powered jack and landed the positive on one of the 30A rated slots on the WFCO DC board. (The two lowest slots are rated for 30A but the rest are rated for 20A.) Although the running amps of these jacks are well below 30A the amps will surge if held at full stroke. As a test I held it fully extended and it even blew my 30A fuse. This was with a Bulldog aftermarket jack.

The easiest thing for you to do is probably a hidden switch outside between the jack and the junction box. This leaves the breakaway power intact at all times and sounds like it still accomplishes your security goal.