Fuses?!?!?

So i have four NAVIGATOR off road lights on a bar on my roof.
Every time i flip them on it blows a fuse and sometimes destroies the casing.
i've tried 20 and 30 amp fuses ?
What do i do?
thanks

 

[Tmac11]

Glad I could help. If your stock the standard wire looms, in the stock locations, were vigorously tested and if anything more was needed it should be noted in most "good" repair manuals. When in doubt check the temperature with a temperature sticker in that area yourself and you'll know what you need.