I have KC hilites fog lights (2) and I have them connected using 16 gauge wire and 10amps fuse.

I had 7.5 amps fuse and it blew up after a little (2 minutes after I turned it on).

is the 10 amps fuse good for 16 gauge wire?

Well using the P=IV formula you have I = 200W/12V = 16.6 Amps. I bet it'll pop the 10 amp fuse too. I think my KC day lighters have a 20A fuse, but I'm not sure. According to this, 20A is a good rule of thumb for 16gauge wire http://www.rowand.net/shop/tech/wirecapacitychart.htm I'd still be cautious with that thin of wire. Is there a reason you ran 16 gauge instead of 14 or 12?

True fog lights are usually 55 watts each so they total 110 watts which draws around 9 amps... but they draw more than that when they're cold when you first throw the switch so I'd go for a 15 amp fuse. I'd also up the wire gauge from 16 to 14 gauge to be safe... 16 is barely adequate for those amps.

If they're 100 watts as some fog lights are, the above numbers are correct but they should be controlled by a relay. You can buy prewired driving light wiring harnesses that include a relay and switch inexpensively from nearly any 4x4 shop.

Do not use that chart on this link for wire capacities. It is misinformation and you will melt your wiring/start a fire.

A good rule is as follows:

#10AWG = 30amps
#12AWG = 20amps
#14AWG = 15 amps

Good call. Wasn't sure where to find reliable numbers for braided wire capacities which raises the question, why isn't OP using #10-12 wire? I tend to go over kill on my projects, but that's just me.

It's the same for house wiring. Amps are amps. Regards.

If they are 100 watt lights, he won't have to worry about any of this by simply buying and installing a pre-wired driving light wiring harness. That makes it easy and provides the right gauge wiring, fuse, switch, and relay... ready to connect, they're made to be installable without any electrical knowledge needed.

Exactly !!


Still have to be careful and do simple OHMS LAW calculations. Even some of the pre wired relay harnesses coming out of China are over-fused.

Not exactly. Slightly smaller gauges are permissible in 12 volt DC automotive wiring due to the fact that the length of the run makes a significant difference. If in doubt, it is always better to err on the conservative side of course.

Not to mention solid core vs braided

Since electron run along the surface of the conductor instead of through it, the stranded wire can carry more amps than solid core wire but in automotive applications, it is not significant enough to differentiate between gauges.

Amps are amps but that doesn't mean wire gauge requirements for 12VDC are the same as 110VAC. See the chart. Your 16 gauge wire is fine to be fused at 20 amps. Plenty for your lights.

You're referring to the skin effect or surface effect which is not in effect with DC power as the OP's lights use. The skin effect is only something that happens with RF (AC), not DC at all, with the higher the frequency the greater the skin effect. Skin effect - Wikipedia, the free encyclopedia

This discussion is getting way too deep for the OP's question.

I used 16 guage wire because thats all I had at the time and I just wanted to mount them.

I now have the 10 amps fuse and it didn't blow. Should I just keep this setup? I left them on for a while (5 minutes) and felt the wire and it wasn't hot.

We can't offer definitive advice until you answer the above posted question of the wattage of the individual fog lights. 55 watts? 100 watts? LED?

ill confirm in the morning. they are not LED for sure.

Pretty sure morning has come and gone...