Best “add a fuse “ tap location in engine compartment fuse box?

Getting ready to install a rough country 30 inch LED light bar… I was thinking of wiring positive relay wire somewhere in the engine compartment fuse box. Thought I could use a “add a fuse” tap somewhere so that the lightbar can only be on if the truck is running .
The light bar is 150 W total… And has a relay built into the wiring harness... directions say to wire relay directly to the battery… But I’d rather have relay wired to an accessory fuse that is only on when the truck is on... any help would be much appreciated… Thanks guys great forum!!

 

Second question… The 150 watt lightbar draws 12.5 Amps...Is it safe to say that I have to use a fuse that is 12.5 Amps or higher ? Like a 15 amp fuse? Sorry I am a total novice

 

Ever get a response on this? i'm curious to hear the answer too haha

 

@15TundraTRD would you habe any advice for this. Ik someone was saying never to use a bigger fuse then the amp draw the other day?

 

ok thanks

 

A 15A fuse will be fine. Main thing is the ampacity of the wire providing voltage to the light bar. The relay won't pull much current, but your wire to the light bar should be at least 12 gauge, but 10 gauge would be advisable if your wire length exceeds about 8 feet. The 15 amp fuse protects the wire carrying the amps, not the light bar itself.

 

15A fuse for a 12.5A load would be fine, the circuit needs to be fused a bit higher than the greatest load expected, otherwise the fuse will blow.

 

Appreciate the help