Tongue Jacks and Circuit Breakers

[Smiletwice]

The low end tongue jack that Forest River included with our trailer started showing signs of stress recently so I purchased a new Husky Brute 4500. Probably overkill for the size of my trailer, but what the heck. Anyway, I'm getting ready to install and this one came with a circuit breaker. I've not seen a circuit breaker on these before and the one I had just had the one power wire go straight to the battery. I'm having trouble imagining when a tongue jack would trip the breaker given that trailer is usually buttoned up with nothing else running when the tongue jack is being used. Anyone with more electrical knowledge than I have care to weigh in on whether this is really necessary? Thanks as always for the insights!

[cavie]

Originally Posted by Smiletwice

The low end tongue jack that Forest River included with our trailer started showing signs of stress recently so I purchased a new Husky Brute 4500. Probably overkill for the size of my trailer, but what the heck. Anyway, I'm getting ready to install and this one came with a circuit breaker. I've not seen a circuit breaker on these before and the one I had just had the one power wire go straight to the battery. I'm having trouble imagining when a tongue jack would trip the breaker given that trailer is usually buttoned up with nothing else running when the tongue jack is being used. Anyone with more electrical knowledge than I have care to weigh in on whether this is really necessary? Thanks as always for the insights!

Yes, it is necessary and your old one had one also. The old one is somewhere between the jack and the battery. It may be automatic or it may have a push button switch in it. The reason for this is the jack is not fused by your 12-volt fuse panel. If you battery disconnect was turn off inside and you were lockout you couldn't use your jacks. How about if your converter wasn't working. You could no remove your TV from the TT. That's why the jack has its own fuse between it and the battery.

[TitanMike]

Fuses and circuit breakers are there to protect the wiring as much as the item that's running. The wire running to the tongue jack can be exposed to damage from lots of directions. A fuse close to where it connects to the battery (or circuit breaker) will make sure that if that wire gets pinched or cut, the resulting short circuit doesn't do damage to whatever is near it or the battery itself. A small wire may be RATED for 20-30 amp but when shorted you might be shocked at how much current can actually pass through it. Enough to bubble the insulation, make a lot of smoke, and even melt the copper which then drops on whatever surface is below it. If that surface is combustible you now have a fire.

Since this is a replacement unit isn't there a manual with it showing a suggested wiring diagram? The last replacement tongue jack I purchased even came with a fuse in the power lead.

[TitanMike]

Originally Posted by cavie

If you battery disconnect was turn off inside and you were lockout you couldn't use your jacks. How about if your converter wasn't working. You could no remove your TV from the TT. That's why the jack has its own fuse between it and the battery.

This is why power tongue jacks also have the manual operation feature. Just pull the rubber plug on the top or side and operate the screw mechanism with the supplied tool or a socket on a Speed Handle/Ratchet.

[BooBoo23]

Sometimes people run the jack up to far and it stalls the motor and will cause the fuse to blow saving the motor. Make sure you don't run the jack against the stops.

[Tundra 2014]

I beat your old jack had a fuse. It cost me $130 to FIND mine. Mine is in a small green plastic fuse holder tucked under the right front part of the "Y" on the frame. I thought it was stupid to put it there, but Titanmike's explanation makes sense. My front slides fuse is in another holder in the same location. I believe we blow both at the same time when I was leveling w/ tongue jack and DW started putting the slide out. DW waits now.