What Size Fuse?????
 

I'm super confused.

I am hooking up some of my items to a fuse block. My CB is the tricky one. It is a Cobra 18 WX ST II.

It has a 1AMP inline fuse. I still need to put a blade fuse on the block where it gets power. Do I put a 1 amp blade? Do they even make those?

15 amp is standard

https://www.yotatech.com/%7Ecorey/te..._box/corey.htm

http://www.4runners.org/articles/cobra/index2.html

bob

Awesome. You got my back. OH WISE ONE :)

I don't think you want a 15 amp fuse on a circut that came with a 1 amp fuse. That is WAY too much of a difference. Use the smallest fuse you can that does not go below the stock 1 amp. 5 would even be better than 15.

Lamm

Well, I still have teh 1 amp fuse inline. I was just hoping to have an equally matched fuse that was more accesible.

The fuse in the block is mainly to protect the wire while the in-line fuse is to protect the device, in this case the CB. So, the block's fuse should be sized for the wire, the idea being that the fuse will let go before the wire catches fire if it were to short. The 1 amp in-line fuse is to protect the inards of the CB in case a short were to happen inside it. I run all my radio stuff off a single 15A fuse in my circuit block. Each device off that circuit has it's own fuse (CB, AM/FM radio, CD changer).

Yeah, but if the CB needs less than 1 amp, hence the 1 amp fuse why would you allow more than 1 amp draw into the wire before the secondary fuse blew???

There is no need to have a higher amp fuse, and a lower one is safer or sure.

Lamm

Sure, you could have a 1A fuse in the block, not sure if that size is available. Also, in a series circuit, current is the same in all parts of the circuit in steady state. So, once the current rises high enough to blow the 1A fuse, the circuit opens and current falls to 0. You could have a 2A, 10A, 100A or whatever fuse in the block, makes no difference to the 1A fuse. A 15A fuse will not "allow" more current into the wire than the circuit/CB can take. Once the current exceeds 1A, the 1A fuse pops. A simpler option would be to hook the 1A fuse to the battery then run that fused wire to the CB, better than having 2 - 1A fuses in series. But, if you start hooking many things to the battery, it gets messy, so the block is added to clean up and separate the circuits. Then you fuse each circuit to protect the wires from the block to the loads. Each load can the have a fuse to protect it.

You are right, there is no reason to risk it. Just make sure the fuse will be able to protect the wire (ie. don't use a 10 amp fuse if the wire behind it can only withstand 8 amps). You could run a 40 amp fuse with a triple O AWG wire to a device that only pulls 1 amp, but that wouldn't be effective. I'd just get a 5 amp fuse.