Should A DC Fuse For A Trailer Jack Be Warm To The Touch

Question:

What might cause my 2016 Jayco X17Zs hybrid travel trailer tongue jack fuse to be rather warm-hot? I can hold it for a while, 5 minutes plus, -surprised that it was really warm! used laser thermometer about 127 degrees F. I am plugged into my home shore power, charging and powering trailer. The jack power switch says off and is not in use.when not in use. Is this normal? I had a problem when I first got the trailer that it kept blowing jack fuses. I got that fixed with proper fusing and I think wiring. They installed a new fuse that has worked with no problems. I just never held the fuse in my hand, I noticed this when winterizing recently. Please help and advise. Thank you!!

asked by: Marcel

Expert Reply:

A fuse can be warm to the touch because it's causing resistance, which is totally normal to an extent. If you're melting the fuse or hurting yourself touching it then you have a problem. There are a number of reasons for this but the most common causes are from a loose connection between the fuse and fuse holder, there's a load on the fuse, or the fuse holder isn't rated high enough for the fuse. You'd need to check the fuse requirements of the specific jack you have and then choose an appropriate gauge wire, fuse holder, and fuse.

The Electric Jack w/ Footplate # EJ-3520-BBX can pull up to 30 amps DC so you would want to use # 10-1-1 gauge wire, a 30 amp fuse holder, and 30 amp fuse with this jack.

expert reply by: Kevin C