Quote: Originally Posted by elemeno0pee
I just got a 30A inline fuse for this setup, and then read that I should not use higher than a 20A... I read this whole thread but can't find the answer, and I just don't know what to search for to find out.
Someone else asked, but it wasn't answered, so I will ask again:
Why can't a 30A inline fuse be used? I don't know anything about electrical junk, but if I had to guess... I'd guess that it's because the fuse will not blow when it might need to?
Thanks
It's all about matching the correct fuse to the correct gauge of wire. You want to make sure you have a fuse that will blow at or before the wire reaches it's maximum recommended Ampere rating.
Here's a chart that show the wire gauge selection for 6V and 12V circuits over different lengths of wire. It also has wattage ratings, so you could just match the wattage of your PSU to the length of wire you need to run.
http://www.rbeelectronics.com/wtable.htm
(Third chart down)
These values are just recommendations, as you'll find lots of charts like that all over the net with different recommendations, but I've found this one to be the best IMO. But I always choose wire at least one gauge larger than what it shows, then select a fuse that's more than the current value your going to be drawing and at or below the rating of the wire.
So for example, if your computer is going to be pulling an average of 20A
@12V over a length of 20' of wire, the recommended gauge is 12. I would then use 10 gauge (slide down to the next lower gauge on that chart under your length), and add a 30A fuse.
Sure there will be people that say "I've ran this and this off that gauge wire for years with no problem...", but a little extra resistance in the wire can make a big difference, resulting in the possibility of your wiring catching fire.